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TRANSCRIPT
Solutions Key
Cover Image Credits Baja copyRadius ImagesCorbis
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Printed in the USA
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7_MCABESK207233_FMCPindd 2 11713 600 PM
Table of Contents
UNIT 1 The Number System
Module 1Lesson 11 1
Lesson 12 2
Lesson 13 3
Lesson 14 4
Module 2Lesson 21 6
Lesson 22 7
Lesson 23 8
Module 3Lesson 31 10
Lesson 32 14
Lesson 33 15
Lesson 34 17
Lesson 35 18
Lesson 36 20
UNIT 2 Ratios and Proportional
Relationships
Module 4Lesson 41 23
Lesson 42 25
Lesson 43 25
Module 5Lesson 51 28
Lesson 52 29
Lesson 53 30
UNIT 3 Expressions Equations
and Inequalities
Module 6Lesson 61 32
Lesson 62 34
Lesson 63 35
Lesson 64 37
Module 7Lesson 71 43
Lesson 72 46
Lesson 73 47
UNIT 4 Geometry
Module 8Lesson 81 53
Lesson 82 54
Lesson 83 54
Lesson 84 55
Module 9Lesson 91 57
Lesson 92 59
Lesson 93 60
Lesson 94 63
Lesson 95 65
UNIT 5 Statistics
Module 10Lesson 101 69
Lesson 102 70
Lesson 103 72
Module 11Lesson 111 74
Lesson 112 75
Lesson 113 76
Copyright copy by Houghton Mifflin Harcourt iiiAll rights reserved
Table of Contents
UNIT 6 Probability
Module 12Lesson 121 79
Lesson 122 81
Lesson 123 82
Lesson 124 82
Module 13Lesson 131 84
Lesson 132 86
Lesson 133 89
Lesson 134 91
Copyright copy by Houghton Mifflin Harcourt ivAll rights reserved
MODULE 1 Adding and Subtracting Integers
Are You Ready
1 an elevator ride down 27 stories -27
2 a $700 profit 700
3 46 degrees below zero -46
4 a gain of 12 yards 12
1 1
5 183
_ + 78
261
261
5 16 17
6 677
_ -288
389
389
1 1
7 1188
_ +902
2090
2090
1 15 14
8 2647
_ -1885
762
762
9
-8-10 -4-6 -2 2 4 6 8 100 10
-8-10 -4-6 -2 2 4 6 8 100 11
-8-10 -4-6 -2 2 4 6 8 100 12
-8-10 -4-6 -2 2 4 6 8 100
LESSON 11
Your Turn
7 -8 + ( -1 ) = -9
8 -3 + ( -7 ) = -10
9 -48 + ( -12 ) = -60
10 -32 + ( -38 ) = -70
11 109 + 191 = 300
12 -40 + ( -105 ) = -145
13 -150 + ( -1500 ) = -1650
14 -200 + ( -800 ) = -1000
Guided Practice
1 a There are 6 counters
b The red counters represent negative numbers
c -5 + ( -1 ) = -6
2 a There are 9 counters
b The red counters represent negative numbers
c -2 + ( -7 ) = -9
3 -5 + ( -2 ) = -7
-8-7-6-5 -2-1 0-4-3 4 -1 + ( -3 ) = -4
-5-4-3-2 1 2 3-1 0 5 -3 + ( -7 ) = -10
-10 -9-8-7 -4-3-2-6-5 6 -4 + ( -1 ) = -5
-5-4-3-2 1 2 3-1 0 7 -2 + ( -2 ) = -4
-5-4-3-2 1 2 3-1 0 8 -6 + ( -8 ) = -14
-16 -12 -4 0-8 9 -5 + ( -4 ) = -9
10 -1 + ( -10 ) = -11
11 -9 + ( -1 ) = -10
12 -90 + ( -20 ) = -110
13 -52 + ( -48 ) = -100
14 5 + ( 198 ) = 203
15 -4 + ( -5 ) + ( -6 ) = -15
16 -50 + ( -175 ) + ( -345 ) = -570
17 Add their absolute values Use the sign of the
integers as the sign of the sum
Solutions KeyThe Number System
UNIT
1
Copyright copy by Houghton Mifflin Harcourt 1 All rights reserved
Independent Practice
18 a
-4
-6
-8
-2
0
2
-5 + (-3)-3 + (-5)
b No -5 + ( -3 ) is -8 and -3 + ( -5 ) is also -8
19 -3 + ( -1 ) + ( -5 ) + ( -2 ) = -11 the golferrsquos total
score is -11
20 -3 + ( -6 ) = -9 the team lost a total of 9 yards
21 -14 + ( -5 ) + ( -12 ) + ( -23 ) = -54 The total
sack yardage was -54
22 a -10 + ( -8 ) = -18
b -6 + ( -2 ) = -8
c -18 lt -8 Jonestown
23 -100 + ( -75 ) + ( -85 ) = -260
Focus on Higher Order Thinking
24 a -25 + ( -45 ) + ( -75 ) = -145 Jan withdrew
$145
b -35 + ( -55 ) + ( -65 ) = -155 Julie withdrew
$155
c Sample answer $45 $55 and $65
25 It is easier to add -80 + ( -20 ) fi rst to get -100
and then add -173 to get -273
26 Disagree there are three pairs of positive integers
1 and 7 2 and 6 and 3 and 5 and three pairs of
negative integers -1 and -7 -2 and -6 -3 and
-5 The absolute value of the sum of any of these
six pairs is 8
LESSON 12
Your Turn
7 -51 + 23
ǀ -51 ǀ - ǀ 23 ǀ = 28
-51 + 23 = -28
8 10 + ( -18 )
ǀ -18 ǀ - ǀ 10 ǀ = 8
10 + ( -18 ) = -8
9 13 + ( -13 )
ǀ 13 ǀ - ǀ -13 ǀ = 0
10 25 + ( -26 )
ǀ -26 ǀ - ǀ 25 ǀ = 1
25 + ( -26 ) = -1
Guided Practice
1 9 + ( -3 ) = 6
2 3 4 5 8 9 106 7 2 -2 + 7 = 5
-3-2-1 0 3 4 51 2 3 -15 + 4 = -11
-18 -16 -12 -10-14 4 1 + ( -4 ) = -3
-5-4-3-2 1 2 3-1 0 5 -4 + 5 = 1
6 -6 + 6 = 0
7 2 + ( -5 ) = -3
8 -3 + 7 = 4
9 -8 + 14 = 6
10 7 + ( -5 ) = 2
11 5 + ( -21 ) = -16
12 14 + ( -14 ) = 0
13 0 + ( -5 ) = -5
14 32 + ( -8 ) = 24
15 To fi nd -4 + 2 start at -4 and move 2 units to the
right to -2 To fi nd the sum -4 + ( -2 ) start at -4
and move 2 units to the left to -6
Independent Practice
16 -15 + 71 = 56
17 -53 + 45 = -8
18 -79 + 79 = 0
19 -25 + 50 = 25
20 18 + ( -32 ) = -14
21 5 + ( -100 ) = -95
22 -12 + 8 + 7 = 3
23 -8 + ( -2 ) + 3 = -7
Copyright copy by Houghton Mifflin Harcourt 2 All rights reserved
24 15 + ( -15 ) + 200 = 200
25 -500 + ( -600 ) + 1200 = 100
26 9 + ( -22 ) = -13 the team lost 13 yards
27 -55 + 275 = 220 the teamrsquos profi t was $220
28 -47 + 47 = 0 Alexrsquos new balance is $0
29 Sample answer 10 and -2 and 12 and -4
30 Bart won Bartrsquos score = 123 + ( -180 ) = -57
points Samrsquos score = 185 + ( -255 ) = -70 points
-57 gt -70 so Bart has the greater score
Focus on Higher Order Thinking
31 Start at -4 and move 3 to the right to reach -1
Start at 3 and move 4 to the left to reach -1
The sums are equivalent by the Commutative
Property of Addition
32 The weight is dropped from 4 feet above the surface
Add -12 to represent the distance the weight falls
before it hits the bottom 4 + ( -12 ) = -8 The water
is 8 feet deep
33 Sample answer A model with more positive
counters than negative counters represents a sum of
two integers whose sum is positive
34 The sign of the other integer is positive and its value
is 6 or greater Sample explanation If you start at
-5 on a number line you have to move to the right 6
or more units to get a sum that is positive
LESSON 13
Your Turn
4 -7 - 2 = -7 + ( -2 )
-7 + ( -2 ) = -9
5 -1 - ( -3 ) = -1 + 3
-1 + 3 = 2
6 3 - 5 = 3 + ( -5 )
3 + ( -5 ) = -2
7 -8 - ( -4 ) = -8 + 4
-8 + 4 = -4
Guided Practice
1 5 - 8 = -3 Start with 5 positive counters
Add 3 zero pairs and remove 8 positive counters
3 negative counters are left so the difference is -3
2 -5 - ( -3 ) = -2 Start with 5 negative counters
and remove 3 negative counters 2 negative
counters are left so the difference is -2
3 -4 - 5 = -4 + ( -5 ) = -9
0-1-2-3-4-5-6-7-8-9 4 1 - 4 = 1 + -4 = -3
0 1 2 3 4-1-2-3-4 5 8 - 11 = 8 + ( -11 ) = -3
6 -3 - ( -5 ) = -3 + 5 = 2
7 15 - 21 = 15 + ( -21 ) = -6
8 -17 - 1 = -17 + ( -1 ) = -18
9 0 - ( -5 ) = 0 + 5 = 5
10 1 - ( -18 ) = 1 + 18 = 19
11 15 - 1 = 14
12 -3 - ( -45 ) = -3 + 45 = 42
13 19 - ( -19 ) = 19 + 19 = 38
14 -87 - ( -87 ) = -87 + 87 = 0
15 To subtract an integer add its opposite Sample
example 6 - 8 = 6 + ( -8 ) = -2
Independent Practice
16 To fi nd the change to Theorsquos account subtract the
initial balance -$4 from the fi nal balance $25
25 - ( -4 ) = 25 + 4 = 29
The overall change is $29
17 To fi nd the change in elevation subtract the
beginning elevation of -225 feet from the fi nal
elevation of -127 feet
-127 - ( -225 ) = -127 + 225 = 98
The change in elevation was 98 feet
18 Subtract the low temperature -2degF from the high
temperature 90degF
90 - ( -2 ) = 92
The difference between the high and low
temperatures is 92degF
19 Subtract Cheyennersquos score at the end of her turn
from her score at the start of her turn to fi nd the
change in Cheyennersquos score during her turn
-425 - ( -275 ) = -425 + 275 = -150
The change in Cheyennersquos score is -150 points
20 a Final temperature - initial temperature = change
in temperature
Gas A -8 - ( -21 ) = -8 + 21 = 13
13degC increase
Gas B 12 - ( -12 ) = 12 + 12 = 24
24degC increase
Gas C -15 - ( -19 ) = -15 + 19 = 4
4degC increase
b Negative the fi nal temperatures will be less than
the initial temperature because the gas is cooler
So the difference in temperatures will be negative
21 Diet Chow the catrsquos weight changed by
-8 + ( -18 ) = -26 ounces with Diet Chow and
3 + ( -19 ) = -16 ounces with Kitty Diet
Focus on Higher Order Thinking
22 Sample answer Susanne owed her sister $4 Then
she borrowed $10 more How much does Susanne
owe her sister in all
23 Tom found -11 - 4 instead of -11 - ( -4 ) To
subtract -4 he should add the opposite of -4
-11 + 4 = -7
Copyright copy by Houghton Mifflin Harcourt 3 All rights reserved
24 YouranswerwillbegreaterthantheintegeryoustartedwithbecausewhenyousubtractanegativeintegeryouadditsoppositeapositiveintegerForexample-5-( -3)=-5+3=-2-2gt-5
25 -16-21-26subtract5togetthenextterm
LESSON 14
Your Turn
1 Starts-Descends+Ascends-40-13+18=-53+18 =-3535feetbelowthecaveentrance
3 Usenegativeintegersforcheckamountsanduseapositiveintegerforamountdeposited-35+( -45)+180=-80+180 =100$100increase
4 JimJim-10-18+5-12=-10-18-12+5 =-( 10+18+12)+5 =-40+5 =-35Jimrestedat-35feet(35feetbelowthesurface)Carla0-20+5-18=0+5-20-18 =0+5-( 20+18) =5-38 =-33Carlarestedat-33feet(33feetbelowthesurface)
Guided Practice
1 -15+ 9- 12= -6- 12 =-1818feetbelowsealevel
2 -23+5-7=-18-7 =-25-25degF
3 50-40+87-30=10+87-30 =97-30 =6767points
4 -6+15+15=-6+30 =24
5 9- 4- 17= 9- 21 =-12
6 50-42+10=8+10 =18
7 6+13+7-5=19+2 =21
8 65+43-11=108-11 =97
9 -35-14+45+31=-49+76 =27
10 -12+6-4=-6-4 =-10-34-3+39=-37+39 = 2 -10lt2( -12+6-4)lt( -34-3+39)
11 21-3+8=18+8 =26-14+ 31- 6= 17- 6 =11 26gt11( 21-3+8)gt( -14+31-6)
12 SampleanswerAddandsubtractfromlefttoright-5+12+10-7=7+10-7=17-7=10
Independent Practice
13 a 5-1+6-1=9
b 9isapositivescoresoitisoverpar
c 9overparislessthan15overparYesCameronbeathisbestgolfscore
14 -6+14-11=-33feetunderground
15 TheCommutativePropertydoesnotapplytosubtraction3-6+5=2and3-5+6=4
16 a -350+275+70-50=-55Leersquosfinalscoreis-55points
b 45gt-55Barry
17 a 300to400
b 75+30-12+14-8+18-30=75+18+6-12=8787customersmustleavebetween400and500
18 100-18+22-53=51$51
19 45-17-22+18=24$24
20 Carlarsquosaccountdecreased$49-18+22-53=-49andLetarsquosaccountonlydecreased$21-17-22+18=-21Carlarsquosaccounthadthegreatestdecreaseinvalue
Focus on Higher Order Thinking
21 SampleanswerTimoweshisbrother1dollarHeborrows6moredollarsfromhisbrotherHepayshisbrotherback3dollarsHowmuchdoesTimstillowehisbrother-1-6+3=-4$4
22 Nothetotalamountshecouldpayherparentsis10+12+25=47and50-47=3Soshestillneeds$3
23 SampleanswerInthecaseinwhichthefirstnumberispositivethenthesumoftheabsolutevaluesoftheothertwonumbersmustbegreaterthanthevalueofthefirstnumberSampleexample13-5-10=-2ǀ 5ǀ+ǀ 10ǀ=15whichisgreaterthan13
MODULE 1
Ready to Go On
1 -8+( -6)=-14
2 -4+( -7)=-11
3 -9+( -12)=-21
CopyrightcopybyHoughtonMifflinHarcourt 4 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U1M01indd 4 103113 206 AM
4 5 + ( -2 )
ǀ 5 ǀ - ǀ -2 ǀ = 3
5 + ( -2 ) = 3
5 -8 + 4
ǀ -8 ǀ - ǀ 4 ǀ = 4
-8 + 4 = -4
6 15 + ( -8 )
ǀ 15 ǀ - ǀ -8 ǀ = 7
15 + ( -8 ) = 7
7 2 - 9 = 2 + ( -9 )
2 + ( -9 ) = -7
8 -3 - ( -4 ) = -3 + 4-3 + 4 = 1
9 11 - ( -12 ) = 11 + 12
11 + 12 = 23
10 -15 + 9 - 4 = -6 - 4
= -10
There are 10 fewer people on the bus
11 24 + 8 - 12 - 9 = 24 + 8 - ( 12 + 9 ) = 32 - 21
= 11
There are 11 cards left in the stack
12 Sample answer Tonya owes her sister $10 and
her friend $5 By how much will her savings change
after she pays them
-10 + ( -5 ) = -15 $15 decrease
Copyright copy by Houghton Mifflin Harcourt 5 All rights reserved
MODULE 2 Multiplying and Dividing Integers
Are You Ready
1 9 times 3 = 27
2 7 times 10 = 70
3 9 times 8 = 72
4 15 times 10 = 150
5 6 times 9 = 54
6 10 times 23 = 230
7 9 times 9 = 81
8 10 times 20 = 200
9 54 divide 9 = 6
10 42 divide 6 = 7
11 24 divide 3 = 8
12 64 divide 8 = 8
13 90 divide 10 = 9
14 56 divide 7 = 8
15 81 divide 9 = 9
16 110 divide 11 = 10
17 12 + 8 divide 212 + 4
16
18 15 - ( 4 + 3 ) times 2
15 - 7 times 2
15 - 14
1
19 18 - ( 8 - 5 ) 2
18 - ( 3 ) 2
18 - 9
9
20 6 + 7 times 3 - 5
6 + 21 - 5
27 - 5
22
21 9 + ( 2 2 + 3 ) 2 times 2
9 + ( 4 + 3 ) 2 times 2
9 + ( 7 ) 2 times 2
9 + 49 times 2
9 + 98
107
22 6 + 5 - 4 times 3 divide 2
6 + 5 - 12 divide 2
6 + 5 - 6
11 - 6
5
LESSON 21
Your Turn
4 Since the numbers have opposite signs the product
will be negative
ǀ -3 ǀ times ǀ 5 ǀ = 3 times 5 = 15
-3 ( 5 ) = -15
5 Since the numbers have the same sign the product
will be positive
ǀ -10 ǀ times ǀ -2 ǀ = 10 times 2 = 20
( -10 ) ( -2 ) = 20
6 One of the factors is 0 so the product is 0
0 ( -22 ) = 0
7 Since the numbers have the same sign the product
will be positive
8 ( 4 ) = 32
Guided Practice
1 -1 ( 9 ) = -9
2 14 ( -2 ) = -28
3 ( -9 ) ( -6 ) = 54
4 ( -2 ) ( 50 ) = -100
5 ( -4 ) ( 15 ) = -60
6 -18 ( 0 ) = 0
7 ( -7 ) ( -7 ) = 49
8 -15 ( 9 ) = -135
9 ( 8 ) ( -12 ) = -96
10 -3 ( -100 ) = 300
11 0 ( -153 ) = 0
12 -6 ( 32 ) = -192
13 7 ( -75 ) = -525 -$525
14 Start at zero and move 5 units to the left 3 times
3 ( -5 ) = -15 the team lost 15 yards
15 6 ( -2 ) = -12 -12degF
16 Multiply the absolute values of the integers If both
integers have the same sign the product is positive
If they have different signs the product is negative
Independent Practice
17 No her number line shows the correct result -6
but she modeled 2 ( -3 ) instead of -2 ( 3 )
18 2 ( -3 ) = -6 he went down 6 floors
19 5 ( -4 ) = -20 $20 decrease
20 Adam descended 5 feet a total of 5 times
5 ( -5 ) = -25 Adam is 25 feet below sea level
21 7 ( -6 ) = -42 the cost of the jeans decreased by
$42 over the 7 weeks
22 9 ( -6 ) = -54 -54 ( 2 ) = -108 Casey has $108
less in his savings
23 7 ( -8 ) = -56 7 ( -5 ) = -35
-56 + ( -35 ) = -91 The savings decreased by $91
24 Sample answer Dave plays a video game in which
he loses 20 points every time he misses a goal
He misses 8 goals 8 ( -20 ) = -160 he loses
160 points
Copyright copy by Houghton Mifflin Harcourt 6 All rights reserved
25 a 3 ( 3 ) ( -3 ) = 9 ( -3 ) = -27
b 3 ( -3 ) ( -3 ) = -9 ( -3 ) = 27
c -3 ( -3 ) ( -3 ) = 9 ( -3 ) = -27
d 3 ( 3 ) ( 3 ) ( -3 ) = 9 ( 3 ) ( -3 ) = 27 ( -3 ) = -81
e 3 ( 3 ) ( -3 ) ( -3 ) = 9 ( -3 ) ( -3 ) = -27 ( -3 ) = 81
f 3 ( -3 ) ( -3 ) ( -3 ) = -9 ( -3 ) ( -3 ) = 27 ( -3 ) = -81
g When a product of integers has an odd number of
negative factors like -3 ( -3 ) ( -3 ) = -27 and
3 ( 3 ) ( 3 ) ( -3 ) = -81 the sign of the product is
negative
When a product of integers has an even number
of negative factors like ( 3 ) ( -3 ) ( -3 ) = 27 and
3 ( 3 ) ( -3 ) ( -3 ) = 9 ( -3 ) ( -3 ) = 81 the sign of the
product is positive
Focus on Higher Order Thinking
26 -1 ( 3 ) ( 1 ) 1 ( -3 ) ( 1 ) -1 ( -3 ) ( -1 )
27 Unless one of the factors is 0 whenever the factors
have opposite signs the product will be less than or
equal to both of the two factors
28 The sign of the product is equal to the sign of the
integers The sign of the product of the first two
integers will always be positive Multiplying this
product by the remaining factor will make a positive
product if the factor is positive negative if it is
negative
LESSON 22
Your Turn
2 Since only the dividend is zero the quotient is 0
0 divide ( -6 ) = 0
3 Since the numbers have opposite signs the quotient
will be negative
38 divide ( -19 ) = -2
4 Since the numbers have the same sign the quotient
will be positive
-13 divide ( -1 ) = 13
5 Yolanda received the same number of penalties in
each game -25 divide ( -5 ) = 5 and -35 divide ( -7 ) = 5
Guided Practice
1 -14 ____ 2 = -7
2 21 divide ( -3 ) = -7
3 26 ____ -13
= -2
4 0 divide ( -4 ) = 0
5 -45 ____ -5 = 9
6 -30 divide ( 10 ) = -3
7 -11 ____ -1
= 11
8 -31 divide ( -31 ) = 1
9 0 ___ -7 = 0
10 -121 _____ -11
= 11
11 84 divide ( -7 ) = -12
12 500 ____ -25
= -20
13 -6 divide ( 0 ) = undefined any number divided by 0 is
undefined
14 -63 ____ -21
= 3
15 -40 divide ( 4 ) = -10 $10
16 -22 divide ( 11 ) = -2 2 points
17 -75 divide ( -15 ) = 5 5 targets
18 -99 divide ( -9 ) = 11 11 times
19 In both cases if the signs of the initial numbers are
the same the answer will be positive If the signs are
different the answer will be negative
Independent Practice
20 -24 divide ( 12 ) = -2 $2
21 Elisa made a greater number of withdrawals She
made -140 divide ( -20 ) = 7 withdrawals Francis made
-270 divide ( -45 ) = 6 withdrawals and 7 gt 6
22 a -2 - 10 = -12 the temperature decreased 12degF
b -12 divide ( 12 ) = -1 decreased by 1degF each hour
23 The first part the rate of change for the first part
is -200 ft _______ 10 min
= -20 ftmin and the rate of change for
the second part is -300 ft _______ 20 min
= -15 ftmin
20 ftmin gt 15 ftmin
24 Sample answer A football team lost 50 yards due to
5 penalties If the team lost the same number of
yards for each penalty what was the change in field
position for each penalty
25 Sample answer a = - 20 and b = 5 less than
-20 divide 5 = -4 and -20 times 5 = -100
-100 lt -4
26 True if the integers have the same sign the product
and quotient are positive if they have different signs
negative
27 False division by 0 is undefined for any dividend
Focus on Higher Order Thinking
28 a 100 divide 25 = 4 4 points
b -16 divide ( -4 ) = 4 Fred answered 4 questions
incorrectly
29 a divide ( -3 ) = 8
a = -24
8 divide b = -4
a divide b = -24 divide ( -2 ) = 12
Copyright copy by Houghton Mifflin Harcourt 7 All rights reserved
30 Dividing integers with the same sign results in a
positive number Since the original two integers are
negative the quotient is greater than both of these
integers
LESSON 23
Your Turn
1 Reggie earned 110 points
3 ( -30 ) + 200 = -90 + 200
= 110
2 -6 ( 13 ) - 21 = -78 - 21
= -99
4 ( -12 ) divide 6 + 2 = -2 + 2
= 0
5 -87 divide ( -3 ) -9 = 29 - 9
= 20
6 40 divide ( -5 ) + 30 = -8 + 30
= 22
7 -39 divide 3 -15 = -13 - 15
= -28
8 Amber moved 3 ( -3 ) + 5 = -4 or 4 places back
Will moved 2 ( -4 ) + 3 = -5 or 5 places back Will
moved further back
9 ( -10 ) divide 2 - 2 = -5 - 2 = -7
( -28 ) divide 4 + 1 = -7 + 1 = -6
10 42 divide ( -3 ) + 9 = -14 + 9 = -5
( -36 ) divide 9 - 2 = -4 - 2 = -6
Guided Practice
1 -6 ( -5 ) + 12 = 30 + 12
= 42
2 3 ( -6 ) - 3 = -18 - 3
= -21
3 -2 ( 8 ) + 7 = -16 + 7
= -9
4 4 ( -13 ) + 20 = -52 + 20
= -32
5 -4 ( 0 ) - 4 = 0 - 4
= -4
6 -3 ( -5 ) - 16 = 15 - 16
= -1
7 7 ( -5 ) + 20 = -35 + 20
= -15
15 dollars less
8 7 ( -10 ) + ( -100 ) = -70 + ( -100 )
= -170
170 fewer points
9 6 ( -4 ) + 10 = -24 + 10
= -14
Ned lost 14 points
10 4 ( -12 ) + 10 = -48 + 10
= -38
$38 less
11 -3 ( -2 ) + 3 = 6 + 3
= 9
3 ( -4 ) + 9 = -12 + 9
= -3
9 gt -3
-3 ( -2 ) + 3 gt 3 ( -4 ) + 9
12 -8 ( -2 ) -20 = 16 -20
= -4
3 ( -2 ) + 2 = - 6 + 2
= -4
-4 = -4
-8 ( -2 ) -20 = 3 ( -2 ) + 2
13 -7 ( 5 ) - 9 = -35 - 9
= -44
-3 ( 20 ) + 10 = -60 + 10
= -50
-44 gt -50
-7 ( 5 ) -9 gt -3 ( 20 ) + 10
14 -16 ( 0 ) -3 = 0 -3
= -3
-8 ( -2 ) -3 = 16 -3
= 13
-3 lt 13
-16 ( 0 ) -3 lt -8 ( -2 ) -3
15 A negative number usually represents a debt
payment or loss or a change that is a decrease
such as to a savings account
Independent Practice
16 -12 ( -3 ) + 7 = 36 + 7
= 43
17 -42 divide ( -6 ) + 5 -8 = 7 + 5 -8
= 12 -8
= 4
18 10 ( -60 ) -18 = -600 -18
= -618
19 ( -11 ) ( -7 ) + 5 - 82 = 77 + 5 - 82
= 82 - 82
= 0
20 35 divide ( -7 ) + 6 = -5 + 6
= 1
21 -13 ( -2 ) - 16 - 8 = 26 - 16 - 8
= 10 - 8
= 2
22 a 5 ( 2 ) -12 + 3 = 10 -12 + 3
= -2 + 3
= 1
b -3 ( 2 ) -1 + 6 + 7 = -6 -1 + 6 + 7
= -7 + 6 + 7
= -1 + 7
= 6
c Rose has more points than Lily so Rose won
the game
23 5 ( -4 ) -8 = -20 - 8 = -28
24 -36 divide ( -4 ) + 9 = 9 + 9 = 18
Copyright copy by Houghton Mifflin Harcourt 8 All rights reserved
25 a 4 ( -35 ) -9 = -140 -9
= -149
$149 less
b Yes $200 - $149 = $51 $51 gt $50 so Arleen
has enough money
26 a 2 ( -10 ) + 3 = -20 + 3= -17
b 7 + 2 + ( -7 ) = 2
c Warren since 2 is greater than -17
d Sample answer 2 of clubs 2 of spades
3 of spades king of diamonds 10 of clubs
7 of clubs
Focus on Higher Order Thinking
27 Sample answer Ann bought three shirts for $7 each
and a pair of pants for $10 Her mother gave her
$25 By how much did the amount of money Ann
had change
28 Disagree the quotient of two integers is positive if
the integers have the same sign So the first two
integers could have been negative integers
29 5 feet equals 60 inches so Lisa is holding the rock
60 inches above the waterrsquos surface The rock will
travel 4 times -5 = -20 inches or 20 inches below the
surface in 4 seconds 60 + 20 = 80 inches
MODULE 2
Ready to Go On
1 Since the numbers have opposite signs the product
will be negative
( -2 ) ( 3 ) = -6
2 Since the numbers have the same sign the product
will be positive
( -5 ) ( -7 ) = 35
3 Since the numbers have the opposite signs the
product will be negative
( 8 ) ( -11 ) = -88
4 ( -3 ) ( 2 ) ( -2 ) = ( -6 ) ( -2 ) = 12
5 5 ( -3 ) = -15 -15degC
6 -63 ____ 7 = -9
7 -15 ____ -3
= 5
8 0 ____ -15
= 0
9 96 ____ -12
= -8
10 -24 divide 6 = -4 -4 Ib
11 ( -4 ) ( 5 ) + 8 = -20 + 8
= -12
12 ( -3 ) ( -6 ) -7 = 18 -7
= 11
13 -27 ____ 9 - 11 = -3 - 11
= -14
14 -24 ____ -3
- ( -2 ) = 8 + 2
= 10
15 Sample answer Maurice lost 3 nickels in the laundry
and found 1 dime in the couch By how much did the
amount of money he had change
( -3 ) ( 5 ) + 10 = -15 + 10 = -5 He had $05 less
than before
Copyright copy by Houghton Mifflin Harcourt 9 All rights reserved
MODULE 3 Rational Numbers
Are You Ready
1 9 ___ 14
times 7 __ 6 =
3
2
9 ___ 14
times 7 __ 6 1
2
= 3 __ 4
2 3 __ 5 times 4 __
7 = 12 ___
35
3 11 ___ 8
times 10 ___ 33
= 1
4
11 ___ 8 times 10 ___
33 5
3
= 5 ___ 12
4 4 __ 9 times 3 =
3
4 __ 9 times 3 __
1 1
= 4 __ 3 or 1 1 __
3
5 1 __ 2 divide 1 __
4 = 1 __
2 times 4 __
1
=
1 1 __ 2 times 4 __
1 2
= 2 __ 1 = 2
6 3 __ 8 divide 13 ___
16 = 3 __
8 times 16 ___
13
= 1 3 __ 8 times 16 ___
13 2
= 6 ___ 13
7 2 __ 5 divide 14 ___
15 = 2 __
5 times 15 ___
14
= 1
1 2 __ 5 times 15 ___
14 3
7
= 3 __ 7
8 4 __ 9 divide 16 ___
27 = 4 __
9 times 27 ___
16
= 1
1 4 __ 9 times 27 ___
16 3
4
= 3 __ 4
9 3 __ 5 divide 5 __
6 = 3 __
5 times 6 __
5
= 18 ___ 25
10 1 __ 4 divide 23 ___
24 = 1 __
4 times 24 ___
23
= 1 1 __ 4 times 24 ___
23 6
= 6 ___ 23
11 6 divide 3 __ 5 = 6 __
1 times 5 __
3
= 2
6 __ 1 times 5 __
3 1
= 10 ___ 1 = 10
12 4 __ 5 divide 10 = 4 __
5 times 1 ___
10
= 2
4 __ 5 times 1 ___
10 5
= 2 ___ 25
13 21 - 6 divide 3
21 - 2
19
14 18 + ( 7 - 4 ) times 3
18 + 3 times 3
18 + 9
27
15 5 + ( 8 - 3 ) 2
5 + ( 5 ) 2
5 + 25
30
16 9 + 18 divide 3 + 10
9 + 6 + 10
15 + 10
25
17 60 - ( 3 - 1 ) 4 times 3
60 - ( 2 ) 4 times 3
60 - 16 times 3
60 - 48
12
18 10 - 16 divide 4 times 2 + 6
10 - 4 times 2 + 6
10 - 8 + 6
2 + 6
8
LESSON 31
Your Turn
0 _
571428
4 7 ⟌ _
40000000 Dividing into 40
_ -35
50
_ -49
10
_ -7
30
_ -28
20
_ -14
60
_ -56
40 Second appearance of 40
Because the number 40 repeats during the division
process the answer is a repeating decimal
-0 _
571428 or -0571428571428hellip
Copyright copy by Houghton Mifflin Harcourt 10 All rights reserved
0 _ 3
5 3 ⟌ _
100 Dividing into 10
_ -3
10 Second appearance of 10
Because the number 10 repeats during the division
process the answer is a repeating decimal 0 _ 3 or
0333hellip
045
6 20 ⟌ _
900
_ -8 0
1 00
_ -1 00
0
-045
7 -2 3 __ 4 = -thinsp 4 times 2 + 3
_________ 4 = -11 ____
4
275
4 ⟌ _
1100
_ -8
30
_ -28
20
_ -20
0
-275 terminating
8 7 1 __ 3 =
3 times 7 + 1 _________
3 = 22 ___
3
7 _ 3
3 ⟌ _
2200 Dividing into 10
_ -21
1 0 Second appearance of 10
Because the number 10 repeats during the division
process the answer is a repeating decimal 7 _ 3 or
7333hellip repeating
Guided Practice
06
1 5 ⟌ _
30
_ -3 0
0
06 terminating
089
2 100 ⟌ _
8900
_ -80 0
9 00
_ -9 00
0
-089 terminating
3 Simplify the fraction
4 ___ 12
= 4 times 1 _____ 4 times 3
= 1 __ 3
0 _ 3
3 ⟌ _
100 Dividing into 10
_ -3
10 Second appearance of 10
Because the number 10 repeats during the division
process the answer is a repeating decimal 0 _ 3 or
0333hellip repeating
0 _
25
4 99 ⟌ _
25000 Dividing into 25
_ -19 8
520
_ -495
25 Second appearance of 25
Because the number 25 repeats during the division
process the answer is a repeating decimal 0 _
25 or
02525hellip repeating
0 _ 7
5 9 ⟌ _
700 Dividing into 70
_ -63
70 Second appearance of 70
Because the number 70 repeats during the division
process the answer is a repeating decimal 0 _ 7 or
-0777hellip repeating
036
6 25 ⟌ _
900
_ -7 5
1 50
_ -1 50
0
-036 terminating
004
7 25 ⟌ _
100
_ -1 00
0
004 terminating
01420 _
45
8 176 ⟌ _
250000000
_ -17 6
7 40
_ -7 04
360
_ -352
80
_ -0
800 First appearance of 800
_ -704
960
_ -880
800 Second appearance of 800
Because the number 800 repeats during the
division process the answer is a repeating decimal
-01420 _
45 or -014204545hellip repeating
0012
9 1000 ⟌ _
12000
_ -10 00
2 000
_ -2 000
0
0012 terminating
Copyright copy by Houghton Mifflin Harcourt 11 All rights reserved
10 -11 1 __ 6 = -thinsp 6 times 11 + 1
_________ 6 = -67 ____
6
111 _ 6
6 ⟌ _
67000
_ -6
07
_ -6
1 0
_ -6
40 First appearance of 40
_ -36
40 Second appearance of 40
Because the number 40 repeats during the division
process the answer is a repeating decimal
- 67 ___ 6
-111 _ 6 or -111666hellip
11 2 9 ___ 10
= 10 times 2 + 9
__________ 10
= 29 ___ 10
29
10 ⟌ _
290
_ -20
9 0
_ -9 0
0
29 ___ 10
29
12 -8 23 ____ 100
= - 100 times 8 + 23
____________ 100
= -823 _____ 100
823
100 ⟌ _
82300
_ -800
23 0
_ -20 0
3 00
_ -3 00
0
-823 _____ 100
-823
13 7 3 ___ 15
= 15 times 7 + 3
__________ 15
= 108 ____ 15
72
15 ⟌ _
1080
_ -105
3 0
_ -3 0
0
108 ____ 15
72
14 54 3 ___ 11
= 11 times 54 + 3
__________ 11
= 597 ____ 11
54 _
27
11 ⟌ _
597000
_ -55
47
_ -44
30 First appearance of 30
_ -22
80
_ -77
30 Second appearance of 30
Because the number 30 repeats during the division
process the answer is a repeating decimal
597 ____ 11
54 _
27 or 542727hellip
15 -3 1 ___ 18
= -thinsp 18 times 3 + 1 __________
18 = -55 ____
18
30 _ 5
18 ⟌ _
55000
_ -54
1 0
_ -0
1 00 First appearance of 100
_ -90
100 Second appearance of 100
Because the number 100 repeats during the division
process the answer is a repeating decimal
-55 ____ 18
-30 _ 5 or -30555hellip
16 3 2 __ 3 =
3 times 3 + 2 _________
3 = 11 ___
3
3 _ 6
3 ⟌ _
1100
_ -9
2 0 First appearance of 20
_ -1 8
20 Second appearance of 20
Because the number 20 repeats during the division
process the answer is a repeating decimal
3 _ 6 or 3666hellip lbs of apples
17 -2 7 __ 8 = -
8 times 2 + 7 _________
8 = -23 ____
8
2875
8 ⟌ _
23000
_ -16
7 0
_ -6 4
60
_ -56
40
_ -40
0
-2875 lb
18 Disagree the definition of a rational number is a
number that can be written as the ratio of two
integers with a denominator not equal to zero and
3 ___ 47
is a well-defined ratio of two integers Tom did
not divide long enough to correctly determine that
the quotient is a repeating decimal
Copyright copy by Houghton Mifflin Harcourt 12 All rights reserved
Independent Practice
19 basketball players
_______________ football players
= 5 ___ 11
0 _
45
11 ⟌ _
5000 Dividing into 50
_ -4 4
60
_ -55
50 Second appearance of 50
Because the number 50 repeats during the division
process the answer is a repeating decimal
5 ___ 11
0 _
45 or 04545hellip repeating
20 hockey players
______________ lacrosse players
= 6 ___ 10
06
10 ⟌ _
60
_ -6 0
0
6 ___ 10
06 terminating
21 polo players
_____________ football players
= 4 ___ 11
036
11 ⟌ _
4000 Dividing into 40
_ -3 3
70
_ -66
40 Second appearance of 40
Because the number 40 repeats during the division
process the answer is a repeating decimal
4 ___ 11
0 _
36 or 03636hellip repeating
22 lacrosse players
______________ rugby players
= 10 ___ 15
= 5 times 2 _____ 5 times 3
= 2 __ 3
0 _ 6
3 ⟌ _
200 Dividing into 20
_ -1 8
20 Second appearances of 20
Because the number 20 repeats during the division
process the answer is a repeating decimal
10 ___ 15
0 _ 6 or 0666hellip repeating
23 football players
_____________ soccer players
= 11 ___ 11
= 1
11 ___ 11
1 terminating
24 Agree Sample answer There are 10 players on the
lacrosse team and dividing the number of any other
team by 10 will simply move the decimal point one
digit to the left Therefore the ratio of any team over
the lacrosse team will be a decimal that terminates
one place to the right of the decimal point
25 a -4 7 __ 8 = -thinsp 8 times 4 + 7
_________ 8 = - 39 ___
8
b 4875
8 ⟌ _
39000
_ -32
7 0
_ -6 4
60
_ -56
40
_ -40
0
-4875
c Sample answer 4 7 __ 8 is very close to 5 Therefore
You could estimate that the water level changes
by 5 inches per month The total change in the
water level at the end of the 3-month period
would be approximately -15 inches
26 integer terminating
27 Ben is taller because Benrsquos height of 5 5 ___ 16
is equal
to 85 ___ 16
or 53125 ft while Marcusrsquo height of 5 7 ___ 24
is
equal to 127 ____ 24
or 52916hellip ft
28 The first store has the better deal because they
offer 3 __ 4 or 075 of a bushel for $9 while the second
store offers only 2 __ 3 or 0666hellip of a bushel for $9
Focus on Higher Order Thinking
29 When the number 1 is the denominator in a fraction
its decimal form is simply the numerator In all other
cases concerning numbers 1 to 10 the division
process stops when either the remainder is 0 or
when the digits begin to repeat When the numbers
2 4 5 or 8 are in the denominator the decimal form
of a fraction will terminate When the numbers
3 6 7 or 9 are in the denominator the decimal form
of a fraction will be a repeating decimal
30 Julie made a higher score on her math test since
her math test score of 21 ___ 23
is equal to a repeating
decimal of approximately 0913 while her science
test score of 29 ___ 32
is equal to a terminating decimal of
090625
Sample answer The difference in scores cannot be
determined by simply comparing the numerators of
the two fractions because the denominators are not
the same For Julie to compare her scores she
needs to divide the denominators into their respec-
tive numerators until one of the quotients is found to
be greater than the other
31 No although the digits in the decimal appear to
follow a pattern a repeating decimal must have the
same combination of digits that repeat such as
0121212hellip
Copyright copy by Houghton Mifflin Harcourt 13 All rights reserved
LESSON 32
Your Turn
2
50 1 2 3 4
3 + 1 1 __ 2 = 4 1 __
2
3
0-7 -6 -5 -4 -3 -2 -1
-25 + ( -45 ) = -7
6
0 1 2-5-6-7-8 -4 -3-2-1
-8 + 5 = -3
7
10-1
1 __ 2 + ( - 3 __
4 ) = - 1 __
4
8
3 4 5 6 7 80 1 2-3-2-1
-1 + 7 = 6
9
3 4 50 1 2-5-4 -3-2-1
2 1 __ 2 + ( -2 1 __
2 ) = 0
10
3 4 50 1 2-5-4 -3-2-1
-45 + 45 = 0
11
1-1 0
3 __ 4 + ( - 3 __
4 ) = 0
The overall change is 0 cups
12 -15 + 35 + 2
-15 + 55
55 - 15
4
13 3 1 __ 4 + ( -2 ) + ( -2 1 __
4 )
3 1 __ 4 + ( -4 1 __
4 )
3 1 __ 4 - 4 1 __
4
-1
14 -275 + ( 325 ) + 5
-6 + 5
-1
15 15 + 8 + ( -3 )
23 + 3
20
Guided Practice
1
3 4 50 1 2-5-4 -3-2-1
-3 + ( -15 ) = -45
2
0 54321-5-4-3-2-1
15 + 35 = 5
3
0 105-1 -05
1 __ 4 + 1 __
2 = 3 __
4
4
0 54321-5-4-3-2-1
-1 1 __ 2 + ( -1 1 __
2 ) = -3
5
0 54321-5-4-3-2-1
3 + ( -5 ) = -2
6
0 54321-5-4-3-2-1
-15 + 4 = 25
7 -2150 + 2150 = 0 $0
8 -874 + 874 = 0 $0
9 275 + ( -2 ) + ( -525 )
275 + ( -725 )
- ( 725 - 275 )
-45
10 -3 + 1 1 __ 2 + 2 1 __
2 = -3 + 4 = 1
11 124 + 92 + 1
-124 + 102
- ( 124 - 102 )
-22
12 -12 + 8 +13
-12 + 21
21 - 12
9
13 45 + ( -12 ) + ( -45 )
45 + ( -45 ) + ( -12 )
0 + ( -12 )
-12
14 1 __ 4 + ( - 3 __
4 ) = - ( 3 __
4 - 1 __
4 ) = - 2 __
4 = - 1 __
2
Copyright copy by Houghton Mifflin Harcourt 14 All rights reserved
15 -4 1 __ 2 + 2 = - ( 4 1 __
2 - 2 ) = -2 1 __
2
16 -8 + ( -1 1 __ 8 ) = -9 1 __
8
17 Start at -4 and move 6 units to the right
The sum is 2
Independent Practice
18 The opposite of +19 is -19
19 -$225 + $1500 = $1500 - $225 = $1275
20 -3525 m + ( -85 ) = -4375 m
21 4 3 __ 4 mi + ( -3 1 __
4 mi ) = 1 2 __
4 mi = 1 1 __
2 mi
22 1635 m + ( -05 m ) = 163 m above sea level
23 30 + 15 - 25 = 45 - 25 = 20 pts
24 January
Income - Expenses
$1205 - $129060
- ( $129060 - $1205 ) -$8560
February
Income - Expenses
$1183 - $134544
-($134544 - $1183)
-$16244
Kameh lost $8560 in January and $16244 in
February
25 June
Income - Expenses
$2413 - $210623
$30677
July
Income - Expenses
$2260 - $195850
$30150
August
Income - Expenses
$2183 - $184512
$33788
Kameh gained $30677 in June $30150 in July and
$33788 in August
26 First sum all the values in the Income column Then
sum all the values in the Expenses column Subtract
the total expenses from the total income Finally add
the $250 profit from December (not shown in the
table) to find the total profit or loss of the bakery by
the end of August
Income = $1205 + $1183 + $1664 + $2413
$2260 + $2183 = $10908
Expenses = $129060 + $134544 + $1664 +$210623 + $195850 + $184512
= $1020989
Profit = $10908 - $1020989 + $250
= $94811
27 -2 is the opposite or additive inverse of 2
28 a 7 ( 10 ) + 3 ( -15 ) = 70 - 45 = 25 pts
b 2 ( 10 ) + 8 ( -15 ) = 20 - 120 = -100 pts
c 10 + 10 + 10 + 10 + 10 + ( ndash15 ) + ( ndash15 ) + ( ndash15 ) +
( ndash15 ) + ( ndash15 ) or 5 ( 10 ) + 5 ( ndash15 )
Focus on Higher Order Thinking
29 The sum of two negative rational numbers is always
negative The sum of a negative rational number and
a positive rational number is negative if the absolute
value of the negative number is greater than that of
the positive number
30 Sample answer The student might have subtracted
the absolute values of the numbers
31 Yes 55 and -55 are opposites and -23 and 23
are opposites so the expression [ 55 + ( -23 ) ] +
( -55 + 23 ) can be viewed as the sum of two
opposites which is always 0
LESSON 33
Your Turn
1
-9 -8 -7 -6 -5 -4
-65 - 2 = -85
2
42 30-1 1
1 1 __ 2 - 2 = - 1 __
2
3
-10-9 -8 -7 -6 -5 -4 -3 -2 -1 0
-225 - 55 = -775
6
1 2-1 0
025 - ( -150 ) = 175
7
1-1 0
- 1 __ 2 - ( - 3 __
4 ) = 1 __
4
Guided Practice
1
1312111098765 14 15
5 - ( -8 ) = 13
2
-9 -8 -7 -6 -5 -4 -3
3 1 __ 2 - 4 1 __
2 = -8
Copyright copy by Houghton Mifflin Harcourt 15 All rights reserved
3
-15 -13 -11 -9 -5-7
-7 - 4 = -11
4
-6 -5 -4 -3 -2 -1 0 1
-05 - 35 = -4
5 -14 - 22 = -36
6 -125 - ( -48 )
-125 + 48
- ( 125 - 48 )
-77
7 1 __ 3 - ( - 2 __
3 ) = 1 __
3 + 2 __
3 = 1
8 65 - ( -14 ) = 65 + 14 = 79
9 - 2 __ 9
- ( -3 )
- 2 __ 9
+ 3
3 - 2 __ 9
2 9 __ 9 - 2 __
9
2 7 __ 9
10 24 3 __ 8
- ( -54 1 __ 8 )
24 3 __ 8
+ 54 1 __ 8
78 4 __ 8
78 1 __ 2
11 -1 m + ( 105 m ) = -15 m
15 m below sea level
12 -12 1 __ 2 + ( -5 ) = -17 1 __
2
17 1 __ 2
or 175 yards
13 Change in height = Starting height - ending height
533 ft - ( -10 ft ) = 533 ft + 10 ft = 543 ft
14 -4500 + (-3015) = -7515 $7515
15 Explain that she is supposed to start at positive 4 on
the number line then move 12 places to the left
because she is subtracting a positive number She
will end on the number -8 which is the answer
Independent Practice
16 -126degC - 75degC = -201degC
17 -2565 ft - 165 ft + 1245 ft = -297 ft
The diver is 297 ft below the surface
18 -9500 ft - ( -26000 ft ) = 16500 ft
19 29035 ft - ( -36198 ft ) = 65233 ft
70000 ft - ( -26000 ft ) = 96000 ft
Mars has the greater difference by
96000 ft - ( 65233 ft ) = 30767 ft
20 a -5degF + 78degF - 32degF
b 78degF - 32degF
c -5degF + 78degF - 32degF 78degF - 5degF - 32degF 78degF - 37degF = 41degF 78degF - 32degF = 46degF
21 a -$1258 + ( -$3072 ) = -$4330
b -$4330 + ( -$25 ) = -$6830
c $6830 since -$6830 + $6830 = 0
22 a No 4 times 52 in = 208 in
b 208 in - 20 in = 08 in more needed
23 a 5 ft - 72 ft + 22 ft
b 5 ft - 72 ft + 22 ft
5 ft + 22 ft - 72 ft
72 ft - 72 ft
= 0 ft because he moved the same distance
backward and forward
24 a Yes
$425 + $089 + $1099
= $1613 lt $20
b $20 - $1613 = $387 left over
Focus on Higher Order Thinking
25 The Commutative Property of Addition (CPA) could
be used to simplify the two terms that already have
a common denominator first
- 7 ___ 16
- 1 __ 4 - 5 ___
16 = ( - 7 ___
16 ) + ( - 1 __
4 ) + ( - 5 ___
16 )
( - 7 ___ 16
) + ( - 5 ___ 16
) + ( - 1 __ 4 ) by CPA
( -7 + ( -5 ) __________
16 ) + ( - 1 __
4 )
( -12 ____ 16
) + ( - 1 __ 4 )
( - 4 times 3 _____ 4 times 4
) + ( - 1 __ 4 )
( - 3 __ 4 ) + ( - 1 __
4 )
( -3 + ( -1 ) __________
4 )
( -4 ___ 4 ) = -1
26 Lowest -225degF + ( -12degF ) = -345degFHighest -195degF + ( -12degF ) = -315degF
27 Sample answer Yes because both numbers are
rational numbers each can be written as the ratio of
two integers for example a __ b
and c __ d
Both fractions
could be given a common denominator and then
one could then be subtracted from the other The
result would be a fraction which is a rational number
28 No Sample answer It is possible for the
difference of two negative numbers to be negative
[ -4 - ( -1 ) = -3 ] but it is also possible for the
difference to be positive [ -5 - ( -8 ) = 3 ]
Copyright copy by Houghton Mifflin Harcourt 16 All rights reserved
LESSON 34
Your Turn
1
-8 -7 -6 -5 -2 -1 0-4 -3
2 ( -35 ) = -7
2
-2 -1 0 1 2 3 4-4 -3
-3 ( -125 ) = 375
4 ( - 3 __ 4 ) ( - 4 __
7 ) ( - 2 __
3 ) = -
13 times 41 times 2 __________ 14 times 7 times 31
= - 1 times 1 times 2 _________ 1 times 7 times 1
= - 2 __ 7
5 ( - 2 __ 3 ) ( - 3 __
4 ) ( 4 __
5 ) = 2 times 31 times 41
__________ 13 times 41 times 5
= 2 times 1 times 1 _________ 1 times 1 times 5
= 2 __ 5
6 ( 2 __ 3 ) ( - 9 ___
10 ) ( 5 __
6 ) = -
12 times 93 times 51
____________ 13 times 210 times 63
= - 1 times 31 times 1 __________ 1 times 2 times 31
= - 1 __ 2
Guided Practice
1
-5 -2 -1 0-4 -3
5 ( - 2 __ 3 ) = 5 __
1 times ( - 2 __
3 )
= - 5 times 2 _____ 1 times 3
= - 10 ___ 3
= -3 1 __ 3
2
-1 -05 0-2 -15
3 ( - 1 __ 4 ) = 3 __
1 times - 1 __
4
= - 3 times 1 _____ 1 times 4
= - 3 __ 4
3
0 1 2-2 -1
-3 ( - 4 __ 7 ) = 3 __
1 times 4 __
7
= 3 times 4 _____ 1 times 7
= 12 ___ 7
= 1 5 __ 7
4
-2 -1 0 1 2 3 4-4 -3
- 3 __ 4 ( -4 ) = 3 __
4 times 4 __
1
= 3 times 41
______ 14 times 1
= 3 times 1 _____ 1 times 1
= 3 __ 1
= 3
5 4 ( -3 ) = -12
6 -18 ( 5 ) = -9
7 -2 ( -34 ) = 68
8 054 ( 8 ) = 432
9 -5 ( -12 ) = 6
10 -24 ( 3 ) = -72
11 1 __ 2 times 2 __
3 times 3 __
4 = ( 1 times 21
______ 12 times 3
) ( 3 __ 4 )
= ( 1 __ 3 ) ( 3 __
4 )
= 1
1 __ 3 times 3 __
4 1
= 1 __ 4
12 - 4 __ 7 ( -thinsp 3 __
5 ) ( - 7 __
3 ) = ( - 4 times 3 _____
7 times 5 ) ( - 7 __
3 )
= 12 ___ 35
( - 7 __ 3 )
= - 4
5 12 times 7 ______ 35 times 3
1
1
= - 4 times 1 _____ 5 times 1
= - 4 __ 5
13 ( - 1 __ 8 ) times 5 times 2 __
3 = ( - 1 __
8 ) times 5 __
1 times 2 __
3
= - 1 times 5 times 21
__________ 48 times 1 times 3
= - 1 times 5 times 1 _________ 4 times 1 times 3
= - 5 ___ 12
Copyright copy by Houghton Mifflin Harcourt 17 All rights reserved
14 ( - 2 __ 3
) ( 1 __ 2 ) ( - 6 __
7 ) = 2 times 1 times 62
__________ 13 times 21 times 7
= 1 times 1 times 2 _________ 1 times 1 times 7
= 2 __ 7
15 4 ( -350 ) = -14 or a $14 change in price
16 18 ( -100 ) = -1800 or a $1800 change
17 Sample answer Count the number of times there is
a negative sign If there are an even number of
negative signs then the final product will be positive
If there is an odd number of negative signs then the
final product will be negative
Independent Practice
18 a 6 ( -1998 ) Note that the change in her bank
account balance does not depend on the initial
amount
b 200 + 6 ( -1998 )
= 200 - 11988
= 8012 $8012
19 Sample answer Start at 0 then move 15 units to
the left (because 15 is negative in this case) 4 times
You are now on -6 Then because 4 is negative in
this case we want to move to the opposite of -6
which is 6
20 8 ( -3 1 __ 4 ) = -8 ( 13 ___
4 )
= - 1
8 __ 1 times 13 ___
4 1
= - 2 times 13 ______ 1 times 1
= - 26 ___ 1
-26 min At the same rate the watch will be
26 minutes behind after 8 weeks
21 3 ( -325 ) = -975 ft The change in depth is -975 ft
Therefore the submarine will be 975 below sea level
(below the surface)
22 5 + ( -3 ) ( 15 )
= 5 + ( -45 )
= 05 cups left
23 Matthew is incorrect Sample answer Matthew
should have said that multiplying by two negatives
is like multiplying the opposite of a positive twice
The opposite of a positive twice brings you back to
a positive
24 5 ( -15 ) = -75 min Therefore she will be late by
75 minutes or 1 hour and 15 minutes
25 Total score is
2 times ( 6 ) + 16 times ( 05 )
+ 7 times ( -05 ) + 2 times ( -15 )
= 12 + 8 - 35 - 3
= 20 - 65
= 135 pts
Focus on Higher Order Thinking
26 Temperature at 5 kilometers
= Temp at ground level + change in temp
= 12 + 5 ( -68 )
= 12 + ( -34 )
= -22degC
27 a b c d
+ + + +
+ + - +
+ - + +
- + + +
- - - +
- - + -
- + - -
+ - - -
28 If the product of two numbers is positive then the two
numbers must have the same sign either they are
both positive or both negative If the sum is negative
then at least one of the numbers must be negative
Therefore the two integers that add to -7 and multiply
to 12 must both be negative The negative paired
factors of 12 are -1 and -12 -2 and -6 and -3
and -4 Of those choices only -3 and -4 add to -7
LESSON 35
Your Turn
3 28 ___ -4
= - 28 ___ 4 = -07
4 -664 ______ -04
= 664 ____ 04
= 166
5 - 55 ___ 05
= - 55 ___ 5 = -11
6 -4256 _______ 112
= -38
The divers change in elevation was -38 feet
per minute
7 - 5 __
8 ___
- 6 __ 7 = - 5 __
8 divide - 6 __
7
= - 5 __ 8 times - 7 __
6
= 35 ___ 48
8 - 5 ___
12 ____
2 __ 3 = - 5 ___
12 divide 2 __
3
= - 5 ___ 12
times 3 __ 2
= - 15 ___ 24
= - 5 __ 8
Copyright copy by Houghton Mifflin Harcourt 18 All rights reserved
9 -4__5
___1__2 =-4__5divide1__
2
=-4__5times2__1
=-8__5
=-13__5
Guided Practice
1 072_____-09=-72___
9 =-08
2 -1__5
___7__5 =-1__
15times5
1__
7=-1times1_____
1times7=-1__7
3 56___-7=-56___7=-8
4 251____4 divide(-3__
8)=251____
4 times-8__
3
=-251times82________
14times3
=-251times2_______1times3
=-502____3
5 75____-1__5
=-75___1times5__
1=-75times5______
1times1=-375
6 -91____-13=91___
13=7
7 -3__7
___9__4 =-
13__7times4__93
=-1times4_____7times3
=-4___21
8 - 12____003
=-1200_____
3 =-400
9 =changeinwaterlevel_________________
changeindays
=-35L______4day
=-0875 L____day
or-0875Lperday
10 =totalchangeinprice_________________
changeindays
=-$4575________5day
=-$915perdayonaverage
11 totalchangeinaltitude___________________
numberofminutes
=-044mi________08min
=-44mi______8min
=-055mileperminute
12 FirstfindthesignofthenumeratorwhichisnegativeNextfindthesignofthedenominatorwhichisnegativeThereforethequotientwillbepositivebecausethenumeratoranddenominatorbothhavethesamesign
Independent Practice
13 5___-2__
8=-5__
1times8__
24
1=-5times4_____
1times1=-20
14 51__3divide(-11__
2)
=-3times5+1_________3 divide2times1+1_________
2
=-16___3divide3__
2
=-16___3times2__
3
=-16times2______3times3
=-32___9
15 -120_____-6 =120____
6 =20
16 -4__5
___-2__
3=
24__5times3__
21=2times3_____
5times1=6__
5
17 103divide(-103)=-103____1 times 1____
103
=-103times1________1times103
=-103____103
=-103____103
=-01
18 -04_____80
=-04___80
=-0005
19 1divide9__5=1__
1times5__
9=5__
9
20 -1___4 ___
23___24
=-1__
14times246
___23
=-1times6______1times23
=-6___23
21 -1035_______-23 =1035_____
23 =45
22 totalhours_____________numberofdays
= 21h______7days
=3 h____day
totaltimelost3 h____day
times3days=9hours
Alexusuallyruns21hoursperweeksodivideby7tofindthatheruns3hoursperdaySinceheisunabletorunfor3dayshistimeisdecreasedby9hoursor-9
23 totalchangeinyards
_________________numberofruns
=-4times15+3___________4 times1__
9
yd___run
=-763___4 times1__
91yd
___run
=-153__
4yd______
9runs
=-153__4times1__
9
yd___run
=-7__4or-13__
4yardsperrun
CopyrightcopybyHoughtonMifflinHarcourt 19 Allrightsreserved
DO NOT EDIT--Changes must be made through File info CorrectionKey=B
7_MCABESK207233_U1M03indd 19 103113 759 PM
24 -121degC + ( -78degC ) + ( -143degC ) + ( -72degC )
_____________________________________ 4
= 414degC ______ 4
= -1035degC per day
25 a total profit
_____________ number of days
= $1750
______ 7 days
= $250 per day
b $150
_____ day
times 7 days = $1050
c total change
_____________ number of days
= - $490
______ 7 days
= -$70 per day
26 total meters descended ___________________ number of seconds
= 996 m ______ 12 s
= 83 ms
27 When converting the division equation into a
multiplication problem he forgot to multiply by the
reciprocal and instead multiplied by the fraction in
the denominator The correct answer is given by
- 3 __
4 ___
4 __ 3
= - 3 __
4 times 3 __
4 = - 9 ___
16
28 -37 m _______ year times ( 2012 ndash 1995 ) years
= -37 m _______ year times 17 years
= -629 m
Focus on Higher Order Thinking
29 Sample answer The average change in temperature
per day would be given by -85 divide 15 if the
temperature were to drop of 85degF over 15 days
-85degF divide 15 d
= - 1785 ____ 315
degF __ d
= - 17 ___ 3 degF __
d or -5 2 __
3 degF __
d asymp -567 degF __
d
On average the temperature changed by -567degF
every day
30 Yes By definition the result of dividing an integer by
a non-zero integer is a rational number
31 Yes The result of dividing an integer by a non-zero
integer always results in a rational number by
definition
LESSON 36
Your Turn
1 Find the total commercial time
3 times 2 1 __ 2 = 7 1 __
2
Find the total entertainment time
30 - 7 1 __ 2 = 22 1 __
2
Find the length of each entertainment segment
22 1 __ 2 divide 4 = 5 5 __
8
Each entertainment segment is 5 5 __ 8 minutes long
2 Find the number of cups of sugar in the bag
454 divide 48 asymp 95
Find the number of 3 __ 4 -cup portions in the bag
95 divide 075 asymp 127
12 batches can be made from the bag of sugar
Find the cost of 1 batch
349 divide 12 asymp 029
The cost of the sugar is $029 per batch
3 Convert the percent to a decimal
12 3 __ 5 = 126
= 0126
Find the worth after 1 year
750 times 0126 = 945
750 + 945 = 8445
Find the worth after 2 years
8445 times 0126 asymp 10641
8445 + 10641 = 95091
Find the worth after 3 years
95091 times 0126 asymp 11981
95091 + 11981 = 107072
The stock is worth $107072
Guided Practice
1 45h times 3 1 __ 5 or 32 miles per hour = 144 miles
144 miles divide 3 3 __ 5 or 36 miles per hour = 4 hours
2 2568 inches times -002375 asymp -061 inches
2568 inches - 061 asymp 2507 inches
3 Sample answer Using a calculator to solve a
problem that involves complicated arithmetic can
help you avoid errors It can also help you to check
solutions to any problems you solved by hand
Independent Practice
4 Find the total weight
78 times 3 = 234
Find the weight each climber carries
234 divide 4 = 585
Each climber carries 585 kg
Copyright copy by Houghton Mifflin Harcourt 20 All rights reserved
5 Find the available width on the page
12 - 3 1 __ 2 = 8 1 __
2
Find half the width
8 1 __ 2 divide 2 = 4 1 __
4
He should put the picture 4 1 __ 4 inches from each side
of the page
6 Find the amount of cereal needed for all the children
11 times 1 __ 3 = 3 2 __
3
10 times 3 __ 4 = 7 1 __
2
3 2 __ 3 + 7 1 __
2 = 11 1 __
6
Compare the total needed with the amount in the
box
11 1 __ 6 lt 12
Yes there is enough Oaties for all the children The
amount needed is 11 1 __ 6 cups and that is less than the
amount in the box 12 cups
7 Find half of the distance that the referee walked
41 3 __ 4 divide 2 = 20 7 __
8
Find how far that distance is from the goal line
50 - 20 7 __ 8 = 29 1 __
8
The referee is 29 1 __ 8 feet from the nearest goal line
8 Donovanrsquos score was 39 ___ 50
= 78 Marcirsquos score was
( 78 + 10 ) = 88
9 Find the number Marci answered correctly
88 = 88 ____ 100
= 44 ___ 50
Find how many more that Marci answered than
Donovan
44 - 39 = 5
Marcie answered 5 more questions correctly than
Donovan
10 Sample answer Donovan got about 40 out of 50
questions right or about 80 Since Marci scored
10 more that is about 90 90 times 50 is 45 So
Marci answered about 45 - 40 or 5 more questions
correctly than Donovan
11 Yes -075 is a reasonable estimate
19 ___ 37
is about 1 __ 2 and 143 is about 15 and
15 times ( - 1 __ 2 ) = -075
12 Sample answer approximately -07343 Use a
calculator Divide -19 by 37 multiply the quotient by
143 then round the product
13 Sample answer Yes -07343 asymp - 075
Focus on Higher Order Thinking
14 Find the time of the descent
-79 9 ___ 10
divide ( -188 ) = 425
Find the time for the ascent
19 1 __ 8 - 1275 - 425 = 2 1 __
8
Find the distance of the ascent
-28 9 ___ 10
- ( -79 9 ___ 10
) = 51
Find the rate of the ascent
51 divide 2 1 __ 8 = 24
The diverrsquos rate of change in elevation during the
ascent was 24 ftmin
15 Sample answer
(1) Convert the mixed number 27 3 __ 5 to the decimal
276 find the sum of 276 and 159 then multiply
the result by 037
(2) Convert the mixed number 27 3 __ 5 to the decimal
276 Then use the Distributive Property so that
(276 + 159)037 = (276)(037) + (159)(037)
Multiply both 276 and 159 by 037 and add the
products I would use the first method because
there are fewer steps and so fewer chances to
make errors
16 Sample answer You need to know how many
gallons of paint you need to paint a wall Measure
the length and width of the wall with a yardstick
then find the area Use the calculator to divide the
area by the number of square feet a gallon of the
paint covers Round up rather than down to the
nearest gallon so you have enough paint
MODULE 3
Ready to Go On
1 4 1 __ 5 =
5 times 4 + 1 _________
5 = 21 ___
5
42
5 ⟌ _
210
_ -20
1 0
_ -1 0
0
42
Copyright copy by Houghton Mifflin Harcourt 21 All rights reserved
2 12 14 ___ 15
= 15 times 12 + 14
___________ 15
= 194 ____ 15
129 _ 3
15 ⟌ _
194000
_ -15
44
_ -30
14 0
_ -13 5
50 first 50
_ -45
50 second 50
Because the number 50 repeats during the division
process the answer is a repeating decimal
129 _ 3 or 12933
3 5 5 ___ 32
= 32 times 5 + 5
__________ 32
= 165 ____ 32
515625
32 ⟌ _
16500000
_ -160
5 0
_ -3 2
1 80
_ -1 60
200
_ -192
80
_ -64
160
_ -160
0
515625
4 45 + 71 = 116
5 5 1 __ 6 + ( -3 5 __
6 ) = 4
6+1 ____
6 -3 5 __
6
= 1 2 __ 6
= 1 1 __ 3
6 - 1 __ 8 -6 7 __
8 = - 1 __
8 + ( -6 7 __
8 )
= -6 8 __ 8
= -7
7 142 - ( -49 ) = 142 + 49
= 191
8 -4 ( 7 ___ 10
) = - 4 __ 1 times 7 ___
10
= - 24 times 7 _______ 1 times 105
= - 2 times 7 _____ 1 times 5
= - 14 ___ 5 or -2 4 __
5
9 -32 ( -56 ) ( 4 ) = 32 times 56 times 4
= 7168
10 - 19 ___ 2 divide 38 ___
7 = -
119 times 7 _______ 2 times 382
= - 1 times 7 _____ 2 times 2
= - 7 __ 4
11 -3201 _______ -33
= 3201 _____ 33
97
33 ⟌ _
3201
_ -297
23 1
_ -23 1
0
97
12 Add the initial stock price with the increase from the
second day
$8360 + $1535 = $9895
Convert the percent decrease to a decimal
-4 3 __ 4 = -475 or -00475
Multiply the price on the second day times the
percent decrease and then subtract the result from
the price on the second day to find the final stock
price
$9895 times -00475 asymp -$47
$9895 - $47 = $9425
The final stock price is $9425 Yes this is
reasonable price on day 1 asymp $85 price on day
2 asymp $100 So the price on day 3 asymp $95
13 Sample answer You can use negative numbers to
represent temperatures below zero or decreases in
prices
Copyright copy by Houghton Mifflin Harcourt 22 All rights reserved
MODULE 4 Ratios and Proportionality
Are You Ready
1 3 __ 4 divide 4 __
5 = 3 __
4 times 5 __
4
= 15 ___ 16
2 5 __ 9 divide 10 ___
11 = 5 __
9 times 11 ___
10
= 1
5 __ 9 times 11 ___
10 2
= 11 ___ 18
3 3 __ 8 divide 1 __
2 = 3 __
8 times 2 __
1
= 4
3 __ 8 times 2 __
1 1
= 3 __ 4
4 16 ___ 21
divide 8 __ 9 = 16 ___
21 times 9 __
8
=thinsp 2
7 16 ___ 21
times 9 __ 8 3
1
= 6 __ 7
5 B ( -4 1 )
6 C ( 3 0 )
7 D ( 5 4 )
8 E ( -2 -2 )
9 F ( 0 0 )
10 G ( 0 -4 )
LESSON 41
Your Turn
3 1 __ 6 acre divide ( 1 __
4 hour ) = 1 __
6 times 4 __
1
= 3
1 times 4 _____ 6 times 1
2
= 1 times 2 _____ 3 times 1
= 2 __ 3 acre per hour
4 3 cups divide ( 3 __ 4 cups ) = 3 __
1 divide 3 __
4
= 3 __ 1 times 4 __
3
= 1
3 times 4 _____ 1 times 3
1
= 1 times 4 _____ 1 times 1
= 4 cups
5 Jaylan 3 __ 4 divide 1 __
5 = 3 __
4 times 5 __
1 = 15 ___
4 = 3 3 __
4
Wanchen 2 __ 3 divide 1 __
6 = 2 ___
1 3 times 6
2 __
1 = 4 __
1 = 4
Jaylanrsquos unit rate is 3 3 __ 4 cups of water per cup of lime
juice Wanchenrsquos unit rate is 4 cups of water per cup
of lime juice Wanchenrsquos limeade has a weaker lime
flavor because 4 gt 3 3 __ 4 and the limeade with a
greater ratio of water to lime juice will have a weaker
flavor
Guided Practice
1
Distance (mi) 8 1 __ 2 17 25 1 __
2 34 42 1 __
2
Time (h) 1 __ 2 1 1 1 __
2 2 2 1 __
2
2 3 1 __ 2 miles divide ( 1 1 __
4 hours ) = 7 __
2 divide 5 __
4 mi ___ h
= 7 times 4 _____ 2 times 5
= 1 7 times 4 _____ 2 times 5
2
= 7 times 2 _____ 1 times 5
= 14 ___ 5 mi ___
h
= 2 4 __ 5 miles per hour
3 5 __ 8 page divide ( 2 __
3 minute ) = 5 __
8 times 3 __
2
= 15 ___ 16
page per minute
4 1 __ 6 foot divide ( 1 __
3 hour ) = 1 __
6 times 3 __
1
= 2 1 times 3 _____ 6 times 1
1
= 1 times 1 _____ 2 times 1
= 1 __ 2 foot per hour
5 5 __ 8 sq ft divide ( 1 __
4 hour ) = 5 __
8 times 4 __
1
= 2 5 times 4 _____ 8 times 1
1
= 5 times 1 _____ 2 times 1
= 5 __ 2 or 2 1 __
2 square feet per hour
Solutions KeyRatios and Proportional Relationships
UNIT
2
Copyright copy by Houghton Mifflin Harcourt 23 All rights reserved
6 240 milligrams divide ( 1 __ 3 pickle ) = 240 ____
1 divide 1 __
3
= 240 ____ 1 times 3 __
1
= 720 ____ 1
Brand Arsquos rate is 720 mg per pickle
325 milligrams divide ( 1 __ 2 pickle ) = 325 ____
1 divide 1 __
2
= 325 ____ 1 times 2 __
1
= 650 ____ 1
Brand Brsquos rate is 650 milligrams per pickle and is
therefore lower than Brand A
7 The unit rate for Ingredient C is
1 __ 4 cup divide ( 2 __
3 serving ) = 1 __
4 times 3 __
2
= 3 __ 8
cup _______
serving
The unit rate for Ingredient D is
1 __ 3 cup divide ( 3 __
4 serving ) = 1 __
3 times 4 __
3
= 4 __ 9
cup _______
serving
To compare 3 __ 8 to 4 __
9 find the least common
denominator of 8 and 9 so that 3 __ 8 = 27 ___
72 and 4 __
9 = 32 ___
72
Therefore ingredient Crsquos unit rate is lower
8 Divide the number in the numerator by the number
in the denominator Write the result with the units of
the rate
For example 1 mile ______
1 __ 2 hour
= 1 __
1 __ 2 = 2 miles per hour
Independent Practice
9 a The unit rate in dollars per hour for On Call is
$10 divide ( 35 hours ) = 10 ___ 35
$ __
h asymp $286 per hour
The unit rate in dollars per hour for Talk Time is
$125 divide ( 1 __ 2 hours ) = 125 ____
05 $ __
h asymp $250 per hour
b Talk Time offers the better deal because its rate in
dollars per hour is lower
c To convert dollars per minute to dollars per hour
multiply by 60
$005 divide ( 1 minute )
= 005 ____ 1
$ ____
min times 60 min ______
1 h
= $3 per hour
d $3 per hour is more expensive than either On Call
or Talk Time so it is not a better deal than either
one
10 a Sample answer 1 __ 2 cup dried fruit to 1 __
8 cup
sunflower seeds in a granola recipe
b The ratio would not change if the recipe were
tripled because both numbers in the ratio would
be multiplied by the same number and therefore
the ratio would still be equivalent to what it was
originally
c 1 __ 2 divide 1 __
8 = 1 ___
1 2 times 8
4 __
1 = 4 __
1 = 4
Sample answer 4 cups dried fruit per 1 cup
sunflower seeds
11 10 songs
____________ 2 commercials
= 5 songs ____________
1 commercials
12 a Terrancersquos rate
6 mi divide ( 1 __ 2 h ) = 6 __
1 times 2 __
1
= 12 miles per hour
Jessersquos rate
2 mi divide ( 15 min ) = 2 __ 1 divide 1 __
4
= 2 __ 1 times 4 __
1 mi ___ h
= 8 miles per hour
b Terrance
50 mi divide ( 12 mi ___ h ) = 50 ___
1 times 1 ___
12
= 50 ___ 12
h
= 4 1 __ 6 h
= 4 10 ___ 60
h
= 4 hours and 10 minutes
Jesse
50 mi divide ( 8 mi ___ h ) = 50 ___
1 times 1 __
8
= 50 ___ 8 h
= 6 1 __ 4 h
= 6 15 ___ 60
h
= 6 hours and 15 minutes
c 8 mi divide ( 45 min ) = 8 __ 1 divide 3 __
4
= 8 __ 1 times 4 __
3
= 32 ___ 3
= 10 2 __ 3 miles per hour
Sandrarsquos unit rate is greater than Jessersquos but
lower than Terrancersquos so she runs slower than
Terrance but faster than Jesse
13 1 ___ 10
h = 6 ___ 60
h = 6 min
300 words _________ 6 min
= 50 words per min
1 ___ 12
h = 5 ___ 60
h = 5 min
300 words _________ 5 min
= 60 words per min
Faster Eli typed 50 words per minute in his first test
and 60 words per minute in his second test
Copyright copy by Houghton Mifflin Harcourt 24 All rights reserved
Focus on Higher Order Thinking
14 a For the 10-pack of 21 ounce bars
$1537 divide 10 bars asymp $154 per bar
For the 12-pack of 14 ounce bars
$1535 divide 12 bars asymp $128 per bar
The 12-pack has the better price per bar
b For the 10-pack
$1537 divide ( 10 times 21 oz ) = 1537 divide 21
asymp $073 per ounce
For the 12-pack
$1535 divide ( 12 times 14 oz ) = 1535 divide 168
asymp $091 per ounce
The 10-pack has a better price per ounce
c Sample answer Since I always eat them one bar
at a time the 12-pack is the better choice
15 Yes Half a room in half a day corresponds to a unit
rate of 1 __ 2 room divide ( 1 __
2 day ) = 1 room _____
day so at the same
rate the painter could paint 7 rooms in 7 days
16 Sample answer Take the reciprocal of the rate For
example a rate of 7 gallons per hour is equal to
1 hour per 7 gallons
LESSON 42
Your Turn
3 No the rates are not equal and therefore her speed
was not constant
4 Since the ratio of students to adults is constant the
relationship between them is proportional
students ________ adults
= 12 ___ 1 = 36 ___
3 = 60 ___
5 = 12 students per adult
If s = the number of students and a = the number
of adults then a = 1 ___ 12
s or s = 12a
Guided Practice
1 45 ___ 1 = 45 90 ___
2 = 45 135 ____
3 = 45 180 ____
4 = 45
The relationship is proportional
2 k = y __ x = 10 ___
2 = 5 y = 5x
3 k = y __ x = 2 __
8 = 1 __
4 y = 1 __
4 x
4 With the equation y = kx where k is the constant
of proportionality
Independent Practice
5 k = y __ x = 74 ___
4 = 1850 y = 1850x
6 $1099
_______ 05 days
= $2198 per day
7 Rent-All because it has the lowest price per day
($1850)
8 100 ft _____ 08 s
= 1000 _____ 8 ft __ s = 125 ft __ s
500 ft _____ 31 s
= 5000 _____ 31
ft __ s asymp 1613 ft __ s
1875 ft ______ 15 s
= 1875 ______ 15
ft __ s asymp 125 ft __ s
No Emtiaz assumed the relationship is proportional
but it is not The rate of change is not constant and
so his answer is not reasonable
9 $3125
______ 5 h
= $625 per hour and $5000
______ 8 h
= $625 per
hour Because the two unit rates are the same the
relationship between charge and time is proportional
10 The constant rate of change in this context means
that Steven charges $625 per hour
11 y = $625x where x is the number of hours Steven
babysits and y is the amount Steven charges
12 y = $625 ( 3 ) = $1875
13 300 ft _____ 2 min
= 6750
_____ 45
= 150 feet per minute
150 ft _____ min
times 60 min ______ 1 h
= 9000 feet per hour
14 y = 150x
15 Sample answer Feet per minute A submarine may
stay submerged for hours but it would not dive for
hours
Focus on Higher Order Thinking
16 Yes because there is a proportional relationship
so the distance and the time would increase by the
same factor
17 Sample answer Yes Even though the rates in the
table are not constant per ear of corn due to
rounding there is a constant rate for every 3 ears
of corn
LESSON 43
Your Turn
1 No because 11 ___ 1 ne 16 ___
2 Also the line drawn through
the points does not go through the origin
5 a The point ( 4 60 ) represents that the bicyclist can
ride a distance 60 miles in 4 hours
b k = 60 mi _____ 4 h
= 15 mi ___ h
c y = 15x where x is time in hours and y is
distance in miles
Guided Practice
1
Time (h) 3 5 9 10
Pages 195 325 585 650
Proportional the rate is a constant 65 pages
per hour
2
Time (h) 2 3 5 8
Earnings 15 2250 3750 60
Proportional the rate of is a constant $750 per hour
Copyright copy by Houghton Mifflin Harcourt 25 All rights reserved
3 Not proportional the relationship is linear but a line
drawn connecting the points will not pass through
the origin of ( 0 0 )
4 Proportional a line can be drawn that passes
through the points and also the origin of ( 0 0 )
5 k = 28 ft ____ 8 s
= 7 __ 2 ft __ s = 35 ft __ s y = 7 __
2 x or y = 35x where
x = time in seconds and y = height in feet
6 k = $2 ______
8 items = 1 __
4
$ _____
items = 025
$ _____
items so y = 1 __
4 x or
y = 025x where x = number of items and
y = cost in dollars
7 The graph is a straight line passing through the
origin
Independent Practice
8 It is the distance ( 0 miles ) that each horse runs in
0 minutes
9 Horse A runs 1 mile in 4 minutes
Horse B runs 1 mile in 25 minutes
10 For Horse A y = 1 __ 4 x
For Horse B y = 1 ___ 25
x or 2 __ 5 x
11 If x is time in minutes and y is distance in miles in
12 minutes Horse A will run 3 miles or 1 __ 4 ( 12 ) = 3
and Horse B will run 48 miles or 2 __ 5 ( 12 ) = 24 ___
5 = 48
12 Students may draw any straight line with a slope
steeper than 2 __ 5 that starts at the origin of ( 0 0 ) An
example is given below
2
2
4
6
8
10
4 6 8 10Time (min)
Dis
tanc
e (m
i)
A
B
O
13 Yes if the train is traveling at a constant speed the
ratio of miles traveled to time in hours will be
constant and therefore a graph comparing miles to
hours will form a straight line that passes through
the origin of ( 0 0 )
14 Sample answer When comparing relationships that
may be easier to observe on a graph than in an
equation
15 a
2
8
16
24
32
40
4 6 8 10DVDs
Cost
($)
O
b Sample answer The graph will pass through the
point ( 4 20 ) This point shows that four DVDs will
cost $20
16 The graph passes through the point ( 4 8 ) so
Glenda swam 8 feet in 4 seconds
17 Yes The graph is linear and passes through the
origin and therefore the rate of distance to time is
proportional at each point on the line
18 k = 8 ft ___ 4 s
= 2 ft __ s so y = 2x where x is time in
seconds and y is distance swam in feet It would
take 22 minutes to swim 1 __ 2 mile at this rate
Focus on Higher Order Thinking
19 Divide the second coordinate by the first to find the
constant of proportionality k Substitute the value of
k into the equation y = kx Then choose a value for x
and solve for y to find the ordered pair
20 Car 3 is not traveling at a constant speed
because 65 ___ 1 ne 85 ___
2
21 Since Car 4 is traveling at twice the speed it will
travel twice the distance as Car 2 in the same
amount of time Therefore the values in Car 4rsquos
distance column will be twice that shown in Car 2rsquos
distance column
MODULE 4
Ready to Go On
1 $140
_____ 18 ft 2
= $778 per square foot
2 $299
_____ 14 lb
asymp $021 per pound
3 $56 ______
25 gal = $224 per gallon
$3205
______ 15 gal
asymp $214 per gallon this is the better deal
4 $160
_____ 5 g
= $3200 per gram this is the better deal
$315
_____ 9 g
asymp $3500 per gram
5 No The ratio of dollars earned to lawns mowed is
not constant 15 ___ 1 ne 48 ___
3
Copyright copy by Houghton Mifflin Harcourt 26 All rights reserved
6 k = $9
___ 8euro
= $27 ____
24euro = 9 __
8 $ __
euro or 1125
$ __
euro So y = 9 __
8 x or
y = 1125x where x equals the number of euros
and y equals their value in dollars
7 The graph passes through the point ( 2 5 )
so k = 5 __ 2 servings
_______ pt
or k = 25 servings
_______ pt
Therefore
y = 5 __ 2
x or y = 25x where x equals the number
of pints and y equals the number of servings
8 The new graph will pass through the points ( 0 0 ) and ( 3 2 )
2
2
4
6
8
10
4 6 8 10Pints
Serv
ings
Frozen Yogurt
O
Therefore y = 2 __ 3 x where x equals the number of
pints and y equals the number of servings
9 Sample answer Compare corresponding values of
the variables to determine whether there is a
constant rate
Copyright copy by Houghton Mifflin Harcourt 27 All rights reserved
MODULE 5 Proportions and Percent
Are You Ready
1 22 = 22 ____ 100
= 022
2 75 = 75 ____ 100
= 075
3 6 = 6 ____ 100
= 006
4 189 = 100 + 89
= 100 ____ 100
+ 89 ____ 100
= 1 + 089
= 189
5 059 = 59
6 098 = 98
7 002 = 2
8 133 = 133
9 64
_ timesthinsp05
320
32
10 30
_ timesthinsp007
210
21
11 160
_ timesthinsp015
800
_ +1600
2400
24
12 62
_ timesthinsp032
124
_ +thinsp1860
1984
1984
13 4
_ timesthinsp12
8
_ +thinsp40
48
48
14 1000
_ timesthinsp006
6000
60
LESSON 51
Your Turn
2 x = ( $64 - 52 )
__________ $52
x = $12
____ $52
asymp 23
4 x = ( 18 - 12 )
________ 18
x = 6 ___ 18
asymp 33
5 x = ( 16 - 10 )
________ 16
x = 6 ___ 16
= 375
8 010 times $499 = $4990
$499 + $4990 = $54890
9 030 times $499 = $14970
$499 - $14970 = $34930
Guided Practice
1 x = ( $8 - $5 )
_________ $5
x = $3
___ $5
= 60
2 x = ( 30 - 20 )
_________ 20
x = 10 ___ 20
= 50
3 x = ( 150 - 86 )
__________ 86
x = 64 ___ 86
asymp 74
4 x = ( $389 - $349 )
______________ $349
x = $040
_____ $349
asymp 11
5 x = ( 14 - 13 )
________ 13
x = 1 ___ 13
asymp 8
6 x = ( 16 - 5 )
________ 5
x = 11 ___ 5 = 220
7 x = ( 64 - 36 )
_________ 36
x = 28 ___ 36
asymp 78
8 x = ( 80 - 64 )
_________ 80
x = 16 ___ 80
= 20
9 x = ( 95 - 68 )
_________ 95
x = 27 ___ 95
asymp 28
Copyright copy by Houghton Mifflin Harcourt 28 All rights reserved
10 x=( 90-45)_________
90
x=45___90
=50
11 x=( 145-132)__________
145
x=13____145
asymp9
12 x=( 64-21)_________
64
x=43___64
asymp67
13 x=( 16-0)________
16
x=16___16
=100
14 x=( 3-1__
2)_______
3
x=21__
2___
3 asymp83
15 010times$900=$090 $900+$090=$990
16 025times48=12 48-12=36cookies
17 020times340=68 $340-68=272pages
18 050times28=14 28+14=42members
19 004times$29000=$1160 $29000-$1160=$27840
20 130times810=1053 810+1053=1863songs
21 030times20=6 20+6=26miles
22 Dividetheamountofchangeinthequantitybytheoriginalamountthenexpresstheanswerasapercent
Independent Practice23
ItemOriginal
PriceNew Price
Percent Change
Increase or
DecreaseBike $110 $96 asympthinsp13 Decrease
Scooter $45 $56 asympthinsp24 Increase
TennisRacket $79 $8295 5 Increase
Skis $580 $435 25 Decrease
24 a 55
x=( 8-3)_______
8 =5__
8=625
x=( 12-7)________
12 =5___
12asymp417
Theamountofchangeisthesamebutthepercentofchangeislessfrom2010to2011
b Changewasgreatestbetween2009and2010
x=( 12-3)________
3
x=9__3=300increase
25 a Amountofchange=( 5-4)=1
Percentdecrease=1__5=20
b $100_____5 =$020each$100_____
4 =$025each
Amountofchange=$025-$020=$005
Percentincrease=$005_____$020
=25
26 Percenterror=( 136-133)___________
136 times100
=03____136
times100asymp2
Focus on Higher Order Thinking
27 a Theyhavethesame$100+$10=$110and$100+10( $100)=$110
b SylviahasmoreLeroihas$110+$10=$120andSylviahas$110+10( $110)=$121
c BecauseSylviawillhavemoreafterthesecondadditionaldepositandshewillbedepositingincreasingamountsshewillalwayshavemoreinheraccount
28 Thefinalamountisalways0becausea100decreaseofanyamountwouldbe0
29 NoOnlythefirstwithdrawalis$10Eachwithdrawalafterthatislessthan$10becauseitis10oftheremainingbalanceTherewillbemoneyleftafter10withdrawals
LESSON 52
Your Turn
2 a 1c+01c11c
b s=11times$28=$3080
3 a 200
b 1c+2c3c
5 a
1b - 024b
1b024b
b 1b-024b=076b
6 a 1p-005p095p
b 095p=$1425
CopyrightcopybyHoughtonMifflinHarcourt 29 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U2M05indd 29 103113 214 AM
Guided Practice
1 a 035s
b 1s + 035s 135s
c 135 times $3200 = $4320
d 035 times $3200 = $1120
Item Price Markup MarkupRetail
Price
2 Hat $18 15 $270 $2070
3 Book $2250 42 $945 $3195
4 Shirt $3375 75 $2531 $5906
5 Shoes $7499 33 $2475 $9974
6 Clock $4860 100 $4860 $9720
7 Painting $18500 125 $23125 $41625
8 $4500 - 022 ( $4500 ) = $3510
9 $8900 - 033 ( $8900 ) = $5963
10 $2399 - 044 ( $2399 ) = $1343
11 $27999 - 075 ( $27999 ) = $7000
12 Write the percent of markdown as a decimal
subtract the product of this decimal and the regular
price from the regular price
Independent Practice
13 a 046b
b 1b - 046b 054b
c 054 times $2900 = $1566
d 046 times $2900 = $1334
14 Regular Price $329
Sale Price $201
Regular Price $419
Sale Price $245
Regular Price $279
Sale Price $115
Regular Price $309
Sale Price $272
Regular Price $377
Sale Price $224
15 a Sample answer original price $100 final price
$050
b Sample answer original price $100 final price
$9950
c Sample answer original price $100 final price
$350
16 p = 127 ( $7400 ) = $9398
s = 127 ( $4800 ) = $6096
j = 127 ( $32500 ) = $41275
2 ( 9398 ) + 3 ( $6096 ) + $41275 = $78359
17 Either buy 3 get one free or 1 __ 4 off Either case would
result in a discount of 25 which is better than 20
Focus on Higher Order Thinking
18 No she is taking a loss Her cost for the tea is t so
the retail price is 12t The discounted price is
08 ( 12t ) or 096t which is less than t
19 No first change 201 decrease second change
251 increase The second percent change is
greater
20 Rafael can purchase the coat after 11 or 12 weeks
after 11 weeks the price is $10932 after 12 weeks
the price is $10385 and after that Danielle donates
the coat
LESSON 53
Your Turn
1 005 times $2000 = $100 $100 + $2000 = $2100
3 005 times $40000 = $2000
$2000 times 4 years = $8000
$40000 + $8000 = $48000
4 Commission $4500 times 00375 = $16875
Total $2200 + $16875 = $236875
Guided Practice
1 005 times $3000 = $150
2 015 times $7000 = $1050
3 0004 times $10000 = $040
4 15 times $2200 = $3300
5 001 times $8000 = $080
6 20 times $500 = $1000
7 a 007 times $4399 = $308
b $4399 + $308 = $4707
8 115 times $7550 = $8683
9 007 times $2000 = $140
$140 times 5 years = $700
10 003 times $550 = $1650
$1650 times 10 years = $165
$550 + $165 = $715
11 a 090 times $20 = $18
b 1085 times $18 = $1953
12 020 times $2999 = $600 tip
00625 times $2999 = $187 tax
$2999 + $600 + $187 = $3786 total
13 Write the tax rate as a decimal Then multiply the
decimal by the price of the item and add the result
to the price
Independent Practice
14 $3275 + $3988 = $7263 total meal cost
014 times $7263 = $1017 tip
$7263 + $1017 = $8280 total with tip
15 $7865 times 015 = $1180 meal discount
$7865 times 020 = $1573 tip
$7865 + $1573 - $1180 = $8258 total
16 $125 times 235 = $29375 retail ring cost
0075 times $29375 = $2203 tax
$29375 + $2203 = $31578 total with tax
Copyright copy by Houghton Mifflin Harcourt 30 All rights reserved
17 $7999 times 012 = $960 discount
$7999 - $960 = $7039 price before tax
$7039 times 10675 = $7514 total with tax
18 4 times $999 times 020 = $799 discount
4 times $999 - $799 = $3197 price before tax
$3197 times 10675 = $3413 total with tax
19 $4500 + 00725 = $32625 commission
$750 + $32625 = $107625 total income
20 $700 times 0055 = $3850 commission
$475 + $3850 = $51350 total income
21 a Multiply Sandrarsquos height by 010 and add the
product to 4 to get Pablorsquos height Then multiply
Pablorsquos height by 008 and add the product to
Pablorsquos height to get Michaelarsquos height
b Using 48 inches for 4 feet
48 inches times 01 = 48 inches so Pablorsquos height is
53 inches or 4 feet 5 inches to the nearest inch
53 inches times 008 = 42 inches so Michaelarsquos
height is 57 inches or 4 feet 9 inches to the
nearest inch
22 a $4998 times 05 = $2499 50 discount
$2499 - $1000 = $1499 $10 discount
b $4998 - $1000 = $3998 $10 discount
$3998 times 05 = $1999 50 discount
23 a $95 times 09 = $8550 discounted camera
$8550 + $1599 = $10149 total
b $1599 times 09 = $1439 discounted battery
$95 + $1439 = $10939 total
c Eric should apply the discount to the digital
camera he can save $8
d $10149 times 008 = $812 tax
$10149 + $812 = $10961 total
24 a Store 1 $22 divide 2 = $11
Store 2 $1299 times 09 = $1169
Store 1 charges $11 per shirt and Store 2
charges $1169 Therefore I would save
$069 per shirt at Store 1
b Store 3 $2098 times 045 = $944
Yes It is selling shirts at $944
Focus on Higher Order Thinking
25 Marcus should choose the option that pays $2400
plus 3 of sales He would make $2550 to $2700
per month The other option would pay only $1775
to $2050 per month
26 Percent error = ǀ 132 - 137 ǀ
____________ 137
times 100 = 05 ____ 137
asymp 36
MODULE 5
Ready to Go On
1 x = ( 63 - 36 )
_________ 36
x = 27 ___ 36
= 75 increase
2 x = ( 50 - 35 )
_________ 50
x = 15 ___ 50
= 30 decrease
3 x = ( 72 - 40 )
_________ 40
x = 32 ___ 40
= 80 increase
4 x = ( 92 - 69 )
_________ 92
x = 23 ___ 92
= 25 decrease
5 $60 times 015 = $9
$60 + $9 = $69
6 $32 times 0125 = $4
$32 + $4 = $36
7 $50 times 022 = $11
$50 - $11 = $39
8 $125 times 030 = $3750
$12500 - $3750 = $8750
9 $4800 times 0065 = $312 commission
$325 + $312 = $637 total income
10 $5310
______ $1735
asymp 31
11 Find the amount per hour that Priya makes if she
makes 20 more than James
$700 times 020 = $140
$700 + $140 = $840
Next find the amount Slobhan makes if he makes
5 less than Priya
$840 times 005 = $042
$840 - $042 = $798
Slobhan makes $798 per hour
12 Both the 6 tax and the 20 tip are applied to the
initial cost of the meal so the two percents can be
added together and multiplied by the cost
$45 times 026 = $1170
$45 + $1170 = $5670
The total cost of the meal is $5670
13 Sample answer sales tax increase discount
decrease tip increase
Copyright copy by Houghton Mifflin Harcourt 31 All rights reserved
MODULE 6 Expressions and Equations
Are You Ready
1 5 + x
2 11 - n
3 -9 ___ y
4 2x - 13
5 2x + 3
= 2 ( 3 ) + 3
= 6 + 3
= 9
6 -4x + 7
= -4 ( 1 ) + 7
= -4 + 7
= 11
7 15x - 25
= 15 ( 3 ) - 25
= 45 - 25
= 2
8 04x + 61
= 04 ( -5 ) + 61
= -20 + 61
= 41
9 2 __ 3 x - 12
= 2 __ 3
( 18 ) - 12
= 2 __ 3
times ( 18 ___ 1 ) - 12
= 36 ___ 3 - 12
= 0
10 - 5 __ 8
x + 10
= - 5 __ 8 ( -8 ) + 10
= - 5 __ 8 times- 8 __
1 + 10
= - 5 ___ 1 8
times- 8 1 __
1 + 10
= - 5 __ 1 times- 1 __
1 + 10
= 5 + 10
= 15
11 1 __ 2 divide 1 __
4
= 1 times 4 _____ 2 times 1
= 1 times 4 2 ______
1 2 times 1
= 1 times 2 _____ 1 times 1
= 2
12 3 __ 8 divide 13 ___
16
= 3 __ 8 times 16 ___
13
= 3 times 16 2 _______
1 8 times 13
= 3 times 2 ______ 1 times 13
= 6 ___ 13
13 2 __ 5 divide 14 ___
15
= 2 __ 5 times 15 ___
14
= 1 2 times 15
3 ________
1 5 times 14 7
= 1 times 3 _____ 1 times 7
= 3 __ 7
14 4 __ 9 divide 16 ___
27
= 4 __ 9 times 27 ___
16
= 1 4 times 27
3 ________
1 9 times 16 4
= 1 times 3 _____ 1 times 4
= 3 __ 4
LESSON 61
Your Turn
2 ( 3x + 1 __ 2 ) + ( 7x - 4 1 __
2 )
= 3x + 7x + 1 __ 2 - 4 1 __
2
= 10x - 4
3 ( -025x - 3 ) - ( 15x + 14 ) = -025x - 3 - 15x - 14
= -175x - 44
4 02(3b - 15c) + 6c
= 06b - 3c + 6c
= 06b + 3c
5 2 __ 3 (6e + 9f - 21g) - 7f
= 4e + 6f - 14g - 7f
= 4e - f - 14g
6 5x - 3(x - 2) - x
= 5x - 3x + 6 - x
= x + 6
7 83 + 34y - 05(12y - 7)
= 83 + 34y - 6y + 35
= 118 - 26y
Solutions KeyExpressions Equations and Inequalities
UNIT
3
Copyright copy by Houghton Mifflin Harcourt 32 All rights reserved
Guided Practice
1 baseballs 14 + (12)n tennis balls 23 + (16)n
14 + 12n + 23 + 16n
14 + 23 + 12n + 16n
37 + 28n
So the total number of baseballs and tennis balls is
37 + 28n
2 37 + 28n
37 + 28 ( 9 )
= 37 + 252
= 289
3 14 + 5(x + 3) - 7x = 14 + 5x + 15 - 7x
= 29 - 2x
4 3 ( t - 4 ) - 8 ( 2 - 3t ) = 3t - 12 - 16 + 24t
= 27t - 28
5 63c - 2 ( 15c + 41 ) = 63c - 3c - 82
= 33c - 82
6 9 + 1 __ 2 ( 7n - 26 ) - 8n = 9 + 35n - 13 - 8n
= -4 - 4 1 __ 2 n
7 2x + 12
2 ( x + 6 )
8 12x + 24
12 ( x + 2 )
9 7x + 35
7 ( x + 5 )
10 You multiply numbers or expressions to produce a
product You factor a product into the numbers or
expressions that were multiplied to produce it
Independent Practice
11 Let d = number of days
Fee for 15 food booths 15 ( 100 + 5d ) Fee for 20 game booths fee 20 ( 50 + 7d ) Amount the company is paid for the booths
15 ( 100 + 5d ) + 20 ( 50 + 7d ) = 15 ( 100 ) + 15 ( 5d ) + 20 ( 50 ) + 20 ( 7d )
= 1500 + 75d + 1000 + 140d
= 1500 + 1000 + 75d + 140d
= 2500 + 215d
12 New length 96 + l
New width 60 + w
Perimeter of new pattern
2(96 + l) + 2(60 + w)
=2(96) + 2l + 2(60) + 2w
192 + 2l + 120 + 2w
192 + 120 + 2l + 2w
312 + 2l + 2w
13 Width 3
Length 1 x-tile and 2 +1-tiles
Factors 3 and x + 2
Product 3 ( x + 2 ) = 3x + 6
14 Width 4
Length 2 x-tiles and 1 -1-tile
Factors 4 and 2x - 1
Product 4 ( 2x - 1 ) = 8x - 4
15 The area is the product of the length and width
( 6 times 9 ) It is also the sum of the areas of the
rectangles separated by the dashed line ( 6 times 5
and 6 times 4 ) So 6 ( 9 ) = 6 ( 5 ) + 6 ( 4 )
16 Perimeter of triangle ( x + 3 ) + ( 2x + 4 ) +
6x = ( x + 3 ) + ( 2x + 4 ) +
6x = 3x + 7 +
-3x = _ -3x
3x = 7 +
_ -7 = _ -7
3x - 7 =
The length of the side is 3x - 7
17 Perimeter of rectangle 2 ( 3x - 3 ) + 2 ( )
10x + 6 = 2 ( 3x - 3 ) + 2 ( )
10x + 6 = 6x - 6 + 2
_ -6x = _ -6x
4x + 6 = - 6 + 2
_ + 6 = _ + 6
4x + 12 = 2
( 4x + 12 ) divide 2 = ( 2 ) divide 2
2x + 6 =
The length of the side is 2x + 6
18 a P = 2l + 2w
Perimeter of tennis court T
2(2x + 6) + 2(x)
= 4x + 12 + 2x
= 6x + 12
Perimeter of basketball court B
2(3x - 14) + 2( 1 __ 2 x + 32)
= 6x - 28 + x + 64
= 7x + 36
b (7x + 36) - (6x + 12)
= 7x + 36 - 6x - 12
= x + 24
c Find the length of tennis court
Let x = 36
2x + 6 = 2 ( 36 ) + 6
= 72 + 6
= 78
Find the width of the basketball court
Let x = 36
1 __ 2 x + 32 = 1 __
2 ( 36 ) + 32
= 18 + 32
= 50
Find the length of the basketball court
Let x = 36
3x - 14 = 3 ( 36 ) - 14
= 108 - 14
= 94
The tennis court is 36 ft by 78 ft The basketball
court is 50 ft by 94 ft
Focus on Higher Order Thinking
19 Find the area of each small square and rectangle
( x ) ( x ) = x 2
( x ) 1 = x
( 1 ) 1 = 1
Copyright copy by Houghton Mifflin Harcourt 33 All rights reserved
x
x
1
11
1 1
x2 x x x
x 1 1 1x 1 1 1
Area =
x 2 + x + x + x + x + x + 1 + 1 + 1 + 1 + 1 + 1
= x 2 + 5x + 6
( x + 3 ) ( x + 2 ) = x 2 + 5x + 6
20 Agree To find 58 times 23 let 23 = 3 + 20 Then find
the product 58 ( 3 + 20 ) First step 58 ( 3 ) = 174
Second step 58 ( 20 ) = 1160 Third step 174 +
1160 = 1334 So 58 ( 23 ) = 58 ( 3 ) + 58 ( 20 )
21 ( 1 ) Think of 997 as 1000 - 3 So 8 times 997 = 8 ( 1000 - 3 ) By the Distributive Property
8 ( 1000 - 3 ) = 8000 - 24 = 7976
( 2 ) Think of 997 as 900 + 90 + 7 By the Distributive
Property 8 ( 900 + 90 + 7 ) = 7200 + 720 + 56 =
7976
LESSON 62
Your Turn
1 49 + z = -9
_ -49 _ -49
z = -139
2 r - 171 = -48
_ +171 _ +171
r = 123
3 -3c = 36
-3c ____ -3
= 36 ___ -3
c = -12
5 x - 15 = 525
_ +15 _ +15
x = 675
The initial elevation of the plane is 675 miles
6 x ___ 35
= -12
x ___ 35
( 35 ) = -12 ( 35 )
x = -42
The decrease in the value of the stock was $420
7 25x = 75
25x ____ 25
= 75 ___ 25
x = 3
The power was restored in 3 hours
Guided Practice
1 Let x represent the number of degrees warmer the
average temperature is in Nov than in Jan
x + ( -134 ) = -17 or x - 134 = -17
x - 134 = -17
_ +134 _ +134
x = 117
The average temperature in November is 117degF
warmer
2 Let x represent the number of days it takes the
average temperature to decrease by 9degF
-1 1 __ 2 x = -9
( - 2 __ 3 ) ( - 3 __
2 x ) = ( - 2 __
3 ) ( -9 )
x = 18 ___ 3
x = 6
It took 6 days for the temperature to decrease by 9degF
3 -2x = 34
-2x ____ -2
= 34 ___ -2
x = -17
4 y - 35 = -21
_ + 35 _ + 35
y = 14
y = 14
5 2 __ 3 z = -6
( 3 __ 2 ) 2z ___
3 = ( 3 __
2 ) ( -6 )
z = -9
6 Sample answer It helps me describe the problem
precisely and solve it using inverse operations
Independent Practice
7 Let x equal the elevation of Mt Everest
x - 870737 = 203215
_ +870737 _ +870 737
x = 2902887
The elevation of Mt Everest is 2902887 ft
8 Let x equal the number of feet Liam descended
2825131 - x = 2320106
_ -2825131 _ -2825131
-x = - 505025
x = 505025
Liam descended 505025 ft
His change in elevation was -505025 ft
9 Let x equal the elevation of Mt Kenya
2825131 - x = 1119421
_ -2825131 _ -2825131
-x = -1705710
x = 1705710
The elevation of Mt Kenya is 170571 ft
10 Find the change in elevation
1250 - 935 = 315
Use an equation
Let x = the number of minutes the balloon
descends
( -22 1 __ 2 ) x = -315
( - 45 ___ 2 ) x = -315
( - 2 ___ 45
) ( - 45 ___ 2 ) x = -315 ( - 2 ___
45 )
x = 14
It will take the balloon 14 minutes to descend
11 Find the change in elevation
4106 - 3205 = 901
Use an equation to find the rate of descent
Copyright copy by Houghton Mifflin Harcourt 34 All rights reserved
Let x = rate of descent
34x = 901
34x ____ 34
= 901 ____ 34
x = 265 = 26 1 __ 2
The rate of descent was 26 1 __ 2 feet per minute
12 Let x = the number of degrees warmer Montanarsquos
average temperature is than Minnesotarsquos
- 25 + x = -07
_ + 25 _ + 25
x = 18
Montanarsquos average 3-month temperature is 18degC
warmer than Minnesotarsquos
13 Let x = the number of degrees warmer Floridarsquos
average temperature is than Montanarsquos
181 - x = -07
_ - 181 _ -181
-x = -188
x = 188
Floridarsquos average 3-month temperature is 188degC
warmer than Montanarsquos
14 Let x = the number of degrees the average
temperature in Texas would have to change
125 + x = 181
_ -125 _ -125
x = 56
It would have to increase by 56degC
15 Let x = the number of yards the team must get on
their next play
-26 1 __ 3
+ x = 10
+26 1 __ 3
______
+26 1 __ 3
______
x = 36 1 __ 3
The team needs to get 36 1 __ 3 yards on their next play
16 Let x = the number of seconds
( -2 1 __ 2 ) x = -156
( -25 ) x = -156
( -25 _____ -25
) x = -156 ______ -25
x = 624
It takes the diver 624 seconds to reach -156 feet
17 Sample answer The elevation is the product of the
rate and the time
18 Let x = the total amount withdrawn
x __ 5 = 455
( 5 ) x __ 5 = 455 ( 5 )
x = 2275
The total amount she withdrew was $22750
Sample answer
$4550 asymp $50 and $50 times 5 = $250 which is close
to $22750
Focus on Higher Order Thinking
19 ( 1 ) The elevations of the diver and the reef both are
below sea level
( 2 ) The change in the planersquos elevation the plane
descends the plane is moving from a higher to a
lower elevation
20 -4x = -48
( -4x ____ -4
) = -48 _____ -4
x = 12
- 1 __ 4 x = -48
( -4 ) ( - 1 __ 4 ) x = -48 ( -4 )
x = 192
192 ____ 12
= 16
In the first case -4x = -48 you divide both sides
by -4 In the second - 1 __ 4 x = -48 you multiply
both sides by -4 The second solution (192) is
16 times the first (12)
21 Add the deposits and the withdrawals Let x repre-
sent the amount of the initial deposit Write and
solve the equation x + deposits - withdrawals =
$21085
LESSON 63
Your Turn
4 Let x represent the number of video games Billy
purchased
Original balance on gift card $150
Cost for x video games $35 middot x
Final balance on gift card $45
Original balance minus $35 times number of games equals $45
darr darr darr darr darr darr darr $150 - $35 middot x = $45
Equation 150 - 35x = 45
5 Sample answer You order x pounds of coffee from
Guatemala at $10 per pound and it costs $40 to
ship the order How many pounds can you order so
that the total cost is $100
Guided Practice
1
+ + ++ ++
+++ + +
+++
2
----
+ ++ ++
- - -
Copyright copy by Houghton Mifflin Harcourt 35 All rights reserved
3 Let a represent the number of adults that attend
Ticket cost for 1 child = $6
Ticket cost for a adults = $9 middot a
Total cost for movie = $78
cost for child plus $9 times number of adults equals $78
darr darr darr darr darr darr darr $6 + $9 middot a = $78
Equation 6 + 9a = 78
4 x is the solution of the problem
2x is the quantity you are looking for multiplied by 2
+ 10 means 10 is added to 2x
= 16 means the result is 16
5 Sample answer A department store is having a sale
on recliners buy two and get a discount of $125
Sanjay purchases two recliners and the total cost
(before taxes) is $400 What is the price of a single
recliner not including any discounts
6 Choose a variable to represent what you want to
find Decide how the items of information in the
problem relate to the variable and to each other
Then write an equation tying this all together
Independent Practice
7 On one side of a line place three negative variable
tiles and seven +1-tiles and then on the other side
place 28 +1-tiles
8 Let d represent the number of days Val rented the
bicycle
Flat rental fee $5500
Cost for d days of rental $850 middot dTotal cost $123
$850 times number of days plus flat fee equals total cost
darr darr darr darr darr darr darr $850 bull d + $55 = $123
Equation 85d + 55 = 123
9 Let r represent the number of refills
Refill mug cost $675
Cost for r refills $125 middot r Total cost $3175
$125 times number of refills plus refill mug cost equals total cost
darr darr darr darr darr darr darr $125 bull r + $675 = $3175
Equation 125r + 675 = 3175
10 Let n represent the number of weekday classes
The Saturday class lasts 60 minutes
The length of time for the weekday classes is 45 middot n
The total number of minutes for all classes in a week
is 28545 minutes times number of plus minutes for equals total minutes
weekday classes Saturday class
darr darr darr darr darr darr darr45 bull n + 60 = 285
Equation 45n + 60 = 285
11 Let n represent the number of African animals
Half the number of African animals is 1 __ 2 n
45 more than the number of African animals
means + 45
The total number of animals is 172
half times number of and 45 more than number equals total number
African animals of African animals of animals
darr darr darr darr darr darr
1 _ 2
bull n + 45 = 172
Equation 1 __ 2 n + 45 = 172
12 Let u represent the number of uniforms
Cost for basketball equipment $548
Cost for u uniforms $2950 middot uTotal cost $2023
$2950 times number of plus cost for basketball equals total cost
uniforms equipment
darr darr darr darr darr darr darr $2950 bull u + $548 = $2023
Equation 295u + 548 = 2023
13 Let x represent the number of weeks
Initial amount in account $500
$20 per week 20 middot xFinal amount in account $220
initial amount minus 20 times number of equals final amount
weeks
darr darr darr darr darr darr darr 500 - 20 bull x = 220
Equation 500 - 20x = 220
14 a The equation adds 25 but Deenarsquos scenario
involves subtracting 25
b Let x represent the number of shirts
Cost of shirts before discount 9 middot xDiscount means subtract
Amount of discount $25
Total bill $88
9 times number of minus discount equals total
shirts bill
darr darr darr darr darr darr darr 9 bull x - 25 = 88
Equation 9x - 25 = 88
c Sample answer I bought some shirts at the store
for $9 each and a pair of jeans for $25 making
my bill a total of $88 How many shirts did I buy
15 a Let c represent the number of children
Flat fee for Sandy $10
Cost per child for Sandy $5 middot cTotal charge for Sandy $10 + $5c
Total charge for Kimmi $25
To compare the two costs set these values equal
Equation 10 + 5c = 25
b Solve the equation to find c the number of
children a family must have for Sandy and Kimmi
to charge the same amount
10 + 5c = 25
10 - 10 + 5c = 25 - 10
5c = 15
5c ___ 5 = 15 ___
5
c = 3
3 children
c They should choose Kimmi because she charges
only $25 If they chose Sandy they would pay
10 + 5 ( 5 ) = $35
Copyright copy by Houghton Mifflin Harcourt 36 All rights reserved
Focus on Higher Order Thinking
16 To get Andresrsquo equation you can multiply every
number in Peterrsquos equation by 4 To get Peterrsquos
equation you can divide every number in Andrewrsquos
equation by 4 or multiply by 1 __ 4
17 Part of the equation is written in cents and part in
dollars All of the numbers in the equation should be
written either in cents or dollars
18 Sample answer Cici has a gift card with a balance
of 60 She buys several T-shirts for $8 each Her new
balance is $28 after the purchases Write an
equation to help find out how many T-shirts Cici
bought
LESSON 64
Your Turn
1 Model the equation
+ ++ +
+ ++ ++ +
+ ++ ++ +
++
Remove 5 +1-tiles from each side of the mat
+ ++ +
+ ++ ++ +
+ ++ ++ +
++
Divide each side into two equal groups
++
+ ++ +
++
The solution is x = 3
++ ++
2 Model the equation
+ + ++ + ++ +
+++
+++
__
Add 1 +1-tile to each side of the mat Note that
a negative-positive tile pair results in zero
+ + ++ + ++
++ +
+++
+++
__
Divide each side into two equal groups
+ + ++++ + +++
The solution is n = 3
+ + +++
3 Model the equation
++++
______
______
____
Add 3 +1-tiles to each side of the mat Note that
a negative-positive tile pair results in zero
++++
+
++
+
++
______
______
____
Divide each side into two equal groups
++++
____
The solution is a = -1
++ __
Copyright copy by Houghton Mifflin Harcourt 37 All rights reserved
4 Model the equation
____
________
++
Add 2 -1-tiles to each side of the mat Note that
a negative-positive tile pair results in zero
________
________
++
____
Divide each side into two equal groups
________
________
We get -y = -1
____
In order to change -y to y add a positive y-variable
tile to each side
++
__ ++ __
Add 1 +1-tile to each side of the mat
++++
__
The solution is y = 1
+++
6 3n + 10 = 37
Solve the equation for n
3n + 10 = 37
-10 ____
-10 ____
3n = 27
3n ___ 3 = 27 ___
3
n = 9
The triplets are 9 years old
7 n __ 4 - 5 = 15
Solve the equation for n
n __ 4 - 5 = 15
+5 ___
+5 ___
n __ 4 = 20
n __ 4 ( 4 ) = 20 ( 4 )
n = 80
The number is 80
8 -20 = 5 __ 9 ( x - 32 )
Solve the equation for x
-20 = 5 __ 9 ( x - 32 )
-20 = 5 __ 9 x - 160 ____
9
+ 160 ____ 9
______
+ 160 ____ 9
______
- 20 ___ 9 = 5 __
9 x
- 20 ___ 9 divide ( 5 __
9 ) = 5 __
9 x divide ( 5 __
9 )
4 20 times 9
1 _______
9 1 times 5
1 = x
- 4 __ 1 = x
-4 = x
The temperature in the freezer is -4degF
9 120 - 4x = 92
Solve the equation for x
120 - 4x = 92
-120 _____
-120 _____
- 4x = -28
-4x ____ -4
= -28 ____ -4
x = 7
She had 7 incorrect answers
Copyright copy by Houghton Mifflin Harcourt 38 All rights reserved
Guided Practice
1 To solve the equation with algebra tiles first remove
one +1-tile from both sides Then divide each side
into two equal groups
2 Remove 1 +1-tile from each side
++++
+ +++++++++
Divide each side into two equal groups
++++
++++++++
The solution is x = 4
++ + + + +
3 Let w = the width of the frame
2 times height plus 2 times width equals perimeter
darr darr darr darr darr darr darr darr darr2 bull 18 + 2 bull w = 58
Solve the equation
2 ( 18 ) + 2w = 58
36 + 2w = 58
36 - 36 + 2w = 58 - 36
2w = 22
2w ___ 2 = 22 ___
2
w = 11
The width is 11 inches
4 1200 minus 25x = 500
Solve the equation for x
1200 - 25x = 500
_ -1200 _ -1200
-25x = -700
-25x _____ -25
= -700 _____ -25
x = 28
The manager will reorder in 28 days
5 Use the inverse operations of the operations
indicated in the problem If the equation does
not involve parentheses use addition or subtraction
before multiplication or division to solve the
equation
Independent Practice
6 9s + 3 = 57
9s + 3 - 3 = 57 - 3
9s = 54
9s ___ 9 = 54 ___
9
s = 6
7 4d + 6 = 42
4d + 6 - 6 = 42 - 6
4d = 36
4d ___ 4 = 36 ___
4
d = 9
8 115 - 3y = -485
115 - 115 - 3y = -485 - 115
thinsp-3y = -60
-3y
____ -3
= -60 ____ -3
y = 20
9 k __ 2 + 9 = 30
k __ 2 + 9 - 9 = 30 - 9
k __ 2 = 21
2 sdot k __ 2 = 2 sdot 21
k = 42
10 g
__ 3 - 7 = 15
g
__ 3 - 7 + 7 = 15 + 7
g
__ 3 = 22
3 sdot g
__ 3 = 3 sdot 22
g = 66
11 z __ 5 + 3 = -35
z __ 5 + 3 - 3 = -35 - 3
z __ 5 = -38
5 sdot z __ 5 = 5 ( -38 )
z = -190
12 -9h - 15 = 93
-9h - 15 + 15 = 93 + 15
-9h = 108
-9h ____ -9 = 108 ____
-9
h = -12
13 - 1 __ 3 (n + 15) = -2
- 1 __ 3 n - 5 = -2
- 1 __ 3 n - 5 + 5 = -2 + 5
- 1 __ 3 n = 3
-3 sdot - 1 __ 3 n = -3 sdot 3
n = -9
14 -17 + b __ 8 = 13
-17 + 17 + b __ 8 = 13 + 17
b __ 8 = 30
8 sdot b __ 8 = 8 sdot 30
b = 240
Copyright copy by Houghton Mifflin Harcourt 39 All rights reserved
15 7 ( c - 12 ) = -21
7c - 84 = -21
_ +84 _ +84
7c = 63
7c ___ 7 = 63 ___
7
c = 9
16 -35 + p
__ 7 = -52
-35 + 35 + p
__ 7 = -52 + 35
p
__ 7 = -17
7 sdot p
__ 7 = -17 sdot 7
p = -119
17 46 = -6t - 8
46 + 8 = -6t - 8 + 8
54 = -6t
54 ___ -6
= -6t ____ -6
t = -9
18 Let a = the original amount in the account
Double the (original plus 26) equals new
sum of amount amount
darr darr darr darr darr darr
2 (a + $26) = $264
Solve the equation
2 ( a + 26 ) = 264
2 ( a + 26 )
_________ 2 = 264 ____
2
a + 26 = 132
a + 26 - 26 = 132 - 26
a = 106
Puja originally had $106 in the account
19 Let t = the temperature 6 hours ago
Twice temperature less 6 degrees equals current
6 hours ago temperature
darr darr darr darr darr darr 2middot t - 6 = 20
Solve the equation
2t - 6 = 20
2t - 6 + 6 = 20 + 6
2t = 26
2t __ 2 = 26 ___
2
t = 13
Six hours ago it was 13 degF in Smalltown
20 -35 = 5 __ 9 ( x - 32 )
-35 = 5 __ 9 x - 160 ____
9
+ 160 ____ 9
______
+ 160 ____ 9
- 155 ____ 9 = 5 __
9 x
thinsp- 155 ____ 9 divide ( 5 __
9 ) = 5 __
9 x divide ( 5 __
9 )
-thinsp 31
155 times 9
1
= x
9 1
times 5
1
- 31 ___ 1 = x
-31 = x
The temperature is -31degF
21 Let a = Artaudrsquos ageopposite of Artaudrsquos age add 40 equals 28
darr darr darr darr darr darr(-) a + 40 = 28
Solve the equation
-a + 40 = 28
-a + 40 - 40 = 28 - 40
-a = -12
-a ___ -1
= -12 ____ -1
a = 12
Artaud is 12 years old
22 Let c = number of customers when Sven startedtwice number of
customers when Sven started
plus 11 more equals present number of customers
darr darr darr darr darr2 middot c +11 = 73
Solve the equation
2c + 11 = 73
2c + 11 - 11 = 73 - 11
2c = 62
2c ___ 2 = 62 ___
2
c = 31
Sven had 31 customers when he started
23 Let p = original price of the jacket
half original less $6 equals amount
price paid
darr darr darr darr darr
1 __ 2
middot p -6 = 88
Solve the equation
1 __ 2 p - 6 = 88
1 __ 2 p - 6 + 6 = 88 + 6
1 __ 2 p = 94
2 sdot 1 __ 2 p = 2 sdot 94
p = 188
The original price was $188
Copyright copy by Houghton Mifflin Harcourt 40 All rights reserved
24 115 minus 8n = 19
Solve the equation for n
115 - 8n = 19
_ -115 _ -115
-8n = -96
-8n _____ -8
= -96 _____ -8
n = 12
They had 19 apples left after 12 days
25 -55x + 056 = -164
-55x + 056 - 056 = -164 - 056
-55x = -22
-55x ______ -22
= -22 _____ -22
x = 04
26 -42x + 315 = -651
-42x + 315 - 315 = -651 - 315
-42x = -966
-42x ______ -42
= -966 ______ -42
x = 23
27 k ___ 52
+ 819 = 472
k ___ 52
+ 819 - 819 = 472 - 819
k ___ 52
= -347
52 sdot k ___ 52
= 52 ( -347 )
k = -18044
28 Sample answer -3x - 5 = -26
29 Sample answer x __ 5 + 10 = 5
30 When dividing both sides by 3 the student forgot to
divide 2 by 3
3x + 2 = 15
3x ___ 3 + 2 __
3 = 15 ___
3
x + 2 __ 3 = 5
- 2 __ 3
___
- 2 __ 3
___
x = 5 - 2 __ 3
x = 5 times3
___ 1
times3 - 2 __
3
x = 15 ___ 3 - 2 __
3
x = 13 ___ 3 or 4 1 __
3
The solution should be x = 4 1 __ 3
31 a 2(x + 40) = 234
Solve the equation for x
2x + 80 = 234
2x + 80 - 80 = 234 - 80
2x = 154
2x ___ 2 = 154 ____
2
x = 77
Trey saved $77
b Sample answer In both solutions you would
divide $234 by 2 then subtract 40 234 divide 2 ndash 40
= 77 These are the same operations applied in
the same order as when solving the equation
Focus on Higher Order Thinking
32 F = 18c + 32
F - 32 = 18c + 32 - 32
F - 32 = 18c
F - 32 ______ 18
= 18c ____ 18
F - 32 ______ 18
= c
33 P = 2 ( ℓ + w ) P = 2ℓ + 2w
P - 2ℓ = 2ℓ - 2ℓ + 2w
P - 2ℓ = 2w
P - 2ℓ ______ 2 = 2w ___
2
P - 2ℓ ______ 2 = w
34 ax + b = c
ax + b - b = c - b
ax = c - b
ax ___ a = c - b ______ a
x = c - b ______ a
MODULE 6
Ready to Go On
1 Add the amounts for the cost of first day of the field
trip with the second day of the field trip where n is
the number of members in the club
15n + 60 + 12n + 95
Therefore the total cost of the two-day field trip can
be written as the expression 27n + 155
2 h + 97 = -97
_ -97 _ -97
h = -194
3 - 3 __ 4 + p = 1 __
2
+ 3 __ 4 + 3 __
4
p = 1 __ 2 + 3 __
4
p = 1 times2
___ 2
times2 + 3 __
4
p = 2 __ 4 + 3 __
4
p = 5 __ 4
4 -15 = -02k
-15 _____ -02
= -02k ______ -02
75 = k
Copyright copy by Houghton Mifflin Harcourt 41 All rights reserved
5 y ___
-3 = 1 __
6
y ___
-3 ( -3 ) = 1 __
6 ( -3 )
y = 1 __ 6 times -3 ___
1
y = -3 ___ 6
y = -1 ___ 2
6 - 2 __ 3
m = -12
- 2 __
3 m _____
- 2 __ 3 = -12 ____
- 2 __ 3
m = -12 divide - 2 __ 3
m = -12 ____ 1 divide - 2 __
3
m = -12 ____ 1 times - 3 __
2
m = -36 ____ -2
m = 18
7 24 = - t ___ 45
24 ( 45 ) = - t ___ 45
( 45 )
108 = -t
-108 = t
8 Let d represent the number of the day after the first
day for example d = 1 means the first day after the
day he started number of number number
2 times day after plus of sit-ups equals of sit-ups
first day first day today
darr darr darr darr darr darr darr
2 middot d + 15 = 33
Equation 2d + 15 = 33
9 5n + 8 = 43
5n + 8 - 8 = 43 - 8
5n = 35
5n ___ 5 = 35 ___
5
n = 7
10 y __
6 - 7 = 4
y __
6 - 7 + 7 = 4 + 7
y __
6 = 11
6 sdot y __
6 = 6 sdot 11
y = 66
11 8w - 15 = 57
8w - 15 + 15 = 57 + 15
8w = 72
8w ___ 8 = 72 ___
8
w = 9
12 g
__ 3 + 11 = 25
g
__ 3 + 11 - 11 = 25 - 11
g
__ 3 = 14
3 sdot g
__ 3 = 3 sdot 14
g = 42
13 f __ 5 - 22 = -25
f __ 5 - 22 + 22 = -25 + 22
f __ 5 = -03
5 sdot f __ 5 = 5 ( -03 )
f = -15
14 - 1 __ 4 (p + 16) = 2
- 1 __ 4 p - 4 = 2
- 1 __ 4 p - 4 + 4 = 2 + 4
- 1 __ 4 p = 6
-4 sdot - 1 __ 4 p = 6 sdot -4
p = -24
15 Sample answer Analyze the situation to determine
how to model it using a two-step equation Solve
the equation Interpret the solution in the given
situation
Copyright copy by Houghton Mifflin Harcourt 42 All rights reserved
MODULE 7 Inequalities
Are You Ready
1 9w = -54
9w ___ 9 = -54 ____
9
w = -6
2 b - 12 = 3
thinsp _ + 12 = _ + 12
b = 15
3 n __ 4
= -11
4 times n __ 4
= 4 ( -11 )
n = -44
4-7
ndash5ndash10 0 5 10
75 4 6
8 3 - (-5)
3 + 5
8
9 -4 - 5
-9
10 6 - 10
-4
11 -5 - (-3)
-5 + 3
-2
12 8 - (-8)
8 + 8
16
13 9 - 5
4
14 -3 - 9
-12
15 0 - (-6)
0 + 6
6
LESSON 71
Your Turn
4 y minus 5 ge minus7
_ +5 _ +5
y ge minus2
-4-5 -3 -2-1 0 1 2 3 4 5
Check Substitute 0 for y
minus1 ge -8
minus1(minus2) le -8(minus2)
2 le 16
5 21 gt 12 + x
_ -12 _ minus12
9 gt x
x lt 9
10 2 3 4 5 6 7 8 9 10
Check Substitute 8 for x
21 gt 12 + 8
21 gt 12 + 8
21 gt 20
6 -10y lt 60
-10y
_____ -10
lt 60 ____ -10
y gt -6
-10-9 -8 -7 -6 -5 -4 -3 -2-1 0 1
Check Substitute -5 for y
-10y lt 60
-10(-5) lt 60
50 lt 60
7 7 ge - t __ 6
7(-6) le - t __ 6 (-6)
-42 le t
t ge -42
-46 -45 -44 -43 -42 -41 -40-47
Check Substitute -36 for t
7 ge - t __ 6
7 ge - ( -36 ____
6 )
7 ge 6
8 Write and solve an inequality
Let m = the number of months
35m le 315
35m ____ 35
le 315 ____ 35
m le 9
Tony can pay for no more than 9 months of his gym
membership using this account
Guided Practice
1 -5 le -2
_ +7 _ +7
2 le 5
2 -6 lt -3
-6 ___ -3
gt -3 ___ -3
2 gt 1
3 7 gt -4
_ -7 _ -7
0 gtthinsp -11
Copyright copy by Houghton Mifflin Harcourt 43 All rights reserved
4 -1 ge -8
-1 ( -2 ) le -8 ( -2 )
2 le 16
5 n - 5 ge -2
_ +5 _ +5
n ge 3
-5 -4 -3 -2-1 0 3 4 51 2
Check Substitute 4 for n
n - 5 ge -2
4 - 5 ge -2
-1 ge -2
6 3 + x lt 7
_ -3 _ -3
x lt 4
-2-1 0 3 4 5 6 7 81 2
Check Substitute 3 for x
3 + x lt 7
3 + 3 lt 7
6 lt 7
7 -7y le 14
-7y
____ -7 ge 14 ___ -7
y ge -2
-5-6-7 -4 -3 -2-1 0 1 2 3
Check Substitute -1 for y
-7y le 14
-7 ( -1 ) le 14
7 le 14
8 b __ 5 gt -1
b __ 5 ( 5 ) gt -1 ( 5 )
b gt -5
-5-6-7-8 -4 -3 -2-1 0 1 2
Check Substitute 0 for b
b __ 5 gt -1
0 __ 5 gt
-1
0 gt -1
9 a -4t ge -80
b -4t ge -80
-4t ____ -4
le -80 ____ -4
t le 20
It will take the physicist 20 or fewer hours to change
the temperature of the metal
c The physicist would have to cool the metal for
more than 20 hours for the temperature of the
metal get cooler than -80deg C
10 You reverse the inequality symbol when you divide
or multiply both sides of an inequality by a negative
number
Independent Practice
11 x - 35 gt 15
_ + 35 _ +35
x gt 50
100 20 30 40 50 60 70 80 90100
Check Substitute 51 for x
x - 35 gt 15
51 minus 35 gt 15
16 gt 15
12 193 + y ge 201
_ -193 _ minus193
y ge 8
10 2 3 4 5 6 7 8 9 10
Check Substitute 9 for y
193 + y ge 201
193 + 9 ge 201
202 ge 201
13 - q
__ 7 ge -1
- q
__ 7 ( -7 ) le -1 ( -7 )
q le 7
8 9 105 6 70 1 2 3 4
Check Substitute ndash14 for q
- q
__ 7 ge -1
- -14 ____ 7 ge
-1
2 ge -1
14 -12x lt 60
-12x _____ -12
gt 60 ____ -12
x gt -5
0-10-9 -8 -7 -6 -5 -4 -3 -2-1
Check Substitute -4 for x
-12x lt 60
-12 ( -4 ) lt 60
48 lt 60
15 5 gt z -3
_ +3 _ +3
8 gt z
z lt 8
10 2 3 4 5 6 7 8 9 10
Check Substitute 7 for z
5 gt z - 3
5 gt 7 - 3
5 gt 4
Copyright copy by Houghton Mifflin Harcourt 44 All rights reserved
16 05 le y __
8
05 ( 8 ) le y __
8 ( 8 )
4 le y
y ge 4
8 9 105 6 70 1 2 3 4
Check Substitute 8 for y
05 le y __
8
05 le 8 __
8
05 le 1
17 Write and solve an inequality
Let x = the number of inches
12 + x le 28
_ -12 _ -12
x le 16
The puppy will grow at most 16 inches more
18 Write and solve an inequality
Let w = the total weight of the kittens
w __ 7 lt 35
w __ 7 ( 7 ) lt 35 ( 7 )
w lt 245
The possible combined weights of the kittens is any
weight less than 245 ounces but greater than 0
19 Write and solve an inequality
Let s = the number of sides
6s le 42
6s ___ 6 le 42 ___
6
s le 7
The length of a side is at most 7 inches
20 Write and solve an inequality
Let x = the amount Tom needs to spend
3025 + x ge 50
_ -3025 _ -3025
x ge 1975
Tom needs to spend at least $1975
21 Write and solve an inequality
Let w = the width of the region
155w ge 1705
155w ______ 155
ge 1705 _____ 155
w ge 11
The possible width of the region is at least 11 feet
22 Write and solve an inequality
Let t = the number of seconds
thinsp-12t lt -120
-12t _____ -12
gt -120 _____ -12
t gt 10
No let t be the number of seconds the descent
takes the inequality is ndash12t lt -120 so t gt 10 so
the submarinersquos descent takes 10 seconds or more
23 Write and solve an inequality
Let s = the amount of spinach
3s le 10
3s ___ 3 le 10 ___
3
s le 3 1 __ 3
The greatest amount of spinach she can buy is 3 1 __ 3
pounds
24 Write and solve an inequality
Let m = the amount of money Gary has
m ___ 05
le 55
m ___ 05
( 05 ) le 55 ( 05 )
m le 275
Gary has at most $275
25 Write and solve an inequality
Let x = the number of pounds of onions
125x le 3
125x _____ 125
le 3 ____ 125
x le 24
No 125x le 3 x le 24 so 24 pounds of onions is
the most Florence can buy 24 lt 25 so she cannot
buy 25 pounds
Focus on Higher Order Thinking
26 If you divide both sides of -7z ge 0 by -7 and do
not reverse the inequality symbol you get z ge 0
This is incorrect because if you choose a value from
the possible solutions such as z = 1 and substitute
it into the original equation you get -7 ge 0 which is
not true
27 x gt 9 for each inequality in each case the number
added to x is 9 less than the number on the right
side of each inequality so x gt 9 is the solution
28 Find the formula for the volume of a rectangular
prism
V = lwh
Write and solve an inequality
Let h = the height in inches
( 13 ) ( 1 __ 2 ) h lt 65
65h lt 65
65h ____ 65
lt 65 ___ 65
h lt 10
All heights greater than 0 in and less than 10 in
( 13 ) ( 1 __ 2 ) h lt 65 65h lt 65 h lt 10 A height cannot
be 0 or less than 0 so h gt 0 and h lt 10
Copyright copy by Houghton Mifflin Harcourt 45 All rights reserved
LESSON 72Your Turn
3 Let a represent the amount each member must
raise
Number of members 45
Starting amount $1240
Target amount $6000
starting number amount each is greater target
amount plus of members times member than or amount
must raise equal to
darr darr darr darr darr darr darr $1240 + 45 middot a ge $6000
Equation 1240 + 45a ge 6000
4 Let n represent the greatest number of rides Ella
can go on
Starting amount $40
Admission price $6
Cost for each ride $3
admission cost for number is less starting
price plus each ride times of rides than or amount
equal to
darr darr darr darr darr darr darr $6 + $3 middot n le $40
Equation 6 + 3n le 40
5 x is the solution of the problem the quantity you
are looking for
3x means that for a reason given in the problem
the quantity you are looking for is multiplied by 3
+ 10 means that for a reason given in the problem
10 is added to 3x
gt 30 means that after multiplying the solution x by
3 and adding 10 to it the result must be greater
than 30
Sample answer An exam consists of one essay
question worth 10 points and several multiple choice
questions worth 3 points each If Petra earns full
points on the essay question how many multiple
choice questions must she get right in order to get
a score greater than 30 points
6 x is the solution of the problem the quantity you are
looking for
5x means that for a reason given in the problem
the quantity you are looking for is multiplied by 5
-50 means that for a reason given in the problem
50 is subtracted from 5x
le 100 means that after multiplying the solution x by
5 and subtracting 50 from it the result must be less
than or equal to 100
Sample answer Miho has $100 to spend on her
garden She spends $50 on gardening supplies
Vegetable plants cost $5 each What is the greatest
number of plants she can buy
Guided Practice
1
- -- -
-
lt
++++++
+ + ++ + +
+
2
---
gt
+ + ++ + +
+ + ++ + +
+ + +
3 Let a represent the amount each member must
raise
Amount to be raised $7000
Amount already raised $1250
Number of members 92 amount number of amount each is greater target
already plus members times member than or amount
raised raises equal to
darr darr darr darr darr darr darr 1250 + 92 times a ge 7000
The inequality that represents this situation is
1250 + 92a ge 7000
4 x is the solution of the problem 7x is the solution
multiplied by 7 -18 means that 18 is subtracted
from 7x le 32 means that the result can be no
greater than 32
5 Sample answer Alexa has $32 to spend on T-shirts
for her friends She has a gift card worth $18 T-shirts
cost $7 each How many T-shirts can Alexa buy
6 Sample answer Choose a variable to represent
what you want to find Decide how the information in
the problem is related to the variable Then write an
inequality
Independent Practice
7 number possible amount is
of times amount each minus for more $200
friends friend earns supplies than
darr darr darr darr darr darr darr 3 middot a - $28 gt $200
3a + 28 gt 200
Let a = possible amount each friend earned
8 cost of number cost of less than amount
bagel times of bagels plus cream or equal Nick
cheese to has
darr darr darr darr darr darr darr $075 middot n + $129 le $700
075n + 129 le 700
Let n = the number of bagels Nick can buy
9 number max amount amount less than total amount
of shirts times each shirt minus of gift or equal Chet can
can cost certificate to spend
darr darr darr darr darr darr darr 4 sdot a - 25 le 75
4a - 25 le 75Let a = the maximum amount each shirt can cost
Copyright copy by Houghton Mifflin Harcourt 46 All rights reserved
10 number of number number of is less total
seats in plus of rows on times seats in than equal number
balcony ground floor one row equal to of people
darr darr darr darr darr darr darr 120 + 32 middot n le 720
120 + 32n le 720
Let n = the number of people in each row
11 amount commission amount greater than earning
earned per plus rate times of sales or equal to for this
month month
darr darr darr darr darr darr darr 2100 + 005 middot s ge 2400
2100 + 005s ge 2400
Let s = the amount of her sales
12 number number average greater
of cans plus of days times number of than goal
collected cans per day
darr darr darr darr darr darr darr 668 + 7 n gt 2000
668 + 7n gt 2000
Let n = the average number of cans collected each
day
13 cost per cost per number of less than total amount
month plus CD times CDs she or equal spent in
buys to a month
darr darr darr darr darr darr darr
$7 + $10 middot c le $100
7 + 10c le 100
Let c = the number of CDs Joanna buys
14 cost of cost for number of less than total amount
belt plus each times shirts he or equal of money
shirt can buy to Lionel has
darr darr darr darr darr darr darr
$22 + $17 middot n le $80
22 + 17n le 80
Let n = the number of shirts he can buy
15 Sample answer Mr Craig is buying pizzas for the
7th grade field day He can spend up to $130 and
needs 15 pizzas He has a $20 coupon How much
can he spend per pizza $10 or less per pizza
16 ldquoat leastrdquo in this case means m ge 25
17 ldquono greater thanrdquo in this case means k le 9
18 ldquoless thanrdquo in this case means p lt 48
19 ldquono more thanrdquo in this case means b le -5
20 ldquoat mostrdquo in this case means h le 56
21 ldquono less thanrdquo in this case means w ge 0
22 The average score of the three tests Marie has
already taken and the three she will still take
is given by
95 + 86 + 89 + 3s
________________ 6
where s is the average score on the three remaining
tests
This value needs to be greater than or equal to 90
so the inequality can be written as
95 + 86 + 89 + 3s
________________ 6 ge 90 or
95 + 86 + 89 + 3s ge 540 or
270 + 3s ge 540
Focus on Higher Order Thinking
23 5 + 10 lt 20 Sample answer If the combined length
of two sides of a triangle is less than the length of
the third side the two shorter sides will not be long
enough to form a triangle with the third side Here
the combined length of 5 ft and 10 ft is 15 ft not
enough to make a triangle
24 -m gt 0 Sample answer Since m is less than 0 it
must be a negative number -m represents the
opposite of m which must be a positive number
since the opposite of a negative number is positive
So -m gt 0
25 n gt 1 __ n if n gt 1
n lt 1 __ n if n lt 1
n = 1 __ n if n = 1
LESSON 73
Your Turn
1 Model the inequality
++
++++
+++
++++
++++
+++
gt
Add seven -1-tiles to both sides of the mat
++
++++
+++
++++
++++
+++
gt
- -- -- --
- -- -- --
Remove zero pairs from both sides of the mat
++
++++
gt
Divide each side into equal groups
++
++++
gt
Copyright copy by Houghton Mifflin Harcourt 47 All rights reserved
The solution is x gt 2
+ + +gt
2 Model the inequality
+++++
----
+++++
+ +++++
ge
Add four +1-tiles to both sides of the mat
+++++
----
+++++
+ ++
++++
+++
++++
ge
Remove zero pairs from the left side of the mat
+++++
+++++
+ +++++
++++
ge
Divide each side into equal groups
+++++
+++++
+ +++++
++++
ge
The solution is h ge 3
+ + + +ge
3 Use inverse operations to solve the inequality
5 - p
__ 6 le 4
5 - 5 - p
__ 6 le 4 - 5
thinsp- p
__ 6 le -1
thinsp-6 ( - p
__ 6 ) ge -6 ( -1 )
p ge 6
Graph the inequality and interpret the circle and
arrow
0 1 4 5 72 3 6 8 9 10
Joshua has to run at a steady pace of at least 6 mih
4 Substitute each value for v in the inequality
3v - 8 gt 22
v = 9 v = 10 v = 11
3 ( 9 ) - 8 gt 22 3 ( 10 ) - 8 gt 22 3 ( 11 ) - 8 gt 22
Evaluate each expression to see if a true inequality
results
3 ( 9 ) - 8 gt 22 3 ( 10 ) - 8 gt
22 3 ( 11 ) - 8 gt
22
27 - 8 gt 22 30 - 8 gt
22 33 - 8 gt
22
19 gt 22 22 gt
22 25 gt
22
not true not true true
v = 11
5 Substitute each value for h in the inequality
5h + 12 le -3
h = -3 h = -4 h = -5
5 ( -3 ) + 12 le -3 5 ( -4 ) + 12 le -3 5 ( -5 ) + 12 le -3
Evaluate each expression to see if a true inequality
results
5 ( -3 ) + 12 le -3 5 ( -4 ) + 12 le
-3 5 ( -5 ) + 12 le
-3
-15 + 12 le -3 -20 + 12 le
-3 -25 + 12 le
-3
-3 le -3 -8 le
-3 -13 le
-3
true true true
h = -3 h = -4 h = -5
Copyright copy by Houghton Mifflin Harcourt 48 All rights reserved
Guided Practice
1 Remove 4 +1-tiles from both sides then divide each
side into 3 equal groups the result is x lt 3
2 Use inverse operations to solve the inequality
5d - 13 lt 32
5d - 13 + 13 lt 32 + 13
5d lt 45
5d ___ 5 lt 45 ___
5
d lt 9
Graph the inequality
20 6 84 10 12 14 16 18 20
3 Use inverse operations to solve the inequality
-4b + 9 le -7
-4b + 9 - 9 le -7 - 9
-4b le -16
-4b ____ -4
ge -16 ____ -4
b ge 4
Graph the inequality
20 6 84 10 12 14 16 18 20
4 Substitute each value for m in the inequality
2m + 18 gt - 4
m = -12 m = -11 m = -10
2 ( -12 ) + 18 gt -4 2 ( -11 ) + 18 gt -4 2 ( -10 ) + 18 gt -4
Evaluate each expression to see if a true inequality
results
2 ( -12 ) + 18 gt -4 2 ( -11 ) + 18 gt
- 4 2 ( -10 ) + 18 gt
- 4
- 24 + 18 gt -4 - 22 + 18 gt
- 4 - 20 + 18 gt
- 4
- 6 gt - 4 - 4 gt
- 4 - 2 gt
- 4
not true not true true
m = -10
5 Substitute each value for y in the inequality
- 6y + 3 ge 0
y = 1 y = 1 __ 2 y = 0
-6 ( 1 ) + 3 ge 0 -6 ( 1 __ 2 ) + 3 ge 0 -6 ( 0 ) + 3 ge 0
Evaluate each expression to see if a true inequality
results
-6 ( 1 ) + 3 ge 0 - 6 ( 1 __
2 ) + 3 ge
0 - 6 ( 0 ) + 3 ge
0
-6 + 3 ge 0 -3 + 3 ge
0 0 + 3 ge
0
-3 ge 0 0 ge
0 3 ge
0
not true true true
y = 1 __ 2
y = 0
6 Solve the inequality
65 - 4t ge 15
65 - 65 - 4t ge 15 - 65
-4t ge -5
-4t ____ -4
le -5 ___ -4
t le 125
Graph the inequality
0 05 1 15 2 25
Lizzy can spend from 0 to 125 h with each student
No 15 h per student will exceed Lizzyrsquos available
time
7 Sample answer Apply inverse operations until you
have isolated the variable If you multiply or divide
both sides of the inequality by a negative number
reverse the direction of the inequality symbol
Independent Practice
8 2s + 5 ge 49
2s + 5 - 5 ge 49 - 5
2s ge 44
2s ___ 2 ge 44 ___
2
s ge 22
10 14 1612 18 20 22 24 26 28 30
9 -3t + 9 ge -21
-3t + 9 - 9 ge -21 -9
-3t ge -30
-3t ____ -3
le -30 ____ -3
t le 10
ndash2ndash4ndash6ndash8ndash10 0 2 4 6 8 10
10 55 gt -7v + 6
55 - 6 gt -7v + 6 - 6
49 gt - 7v
49 ___ -7 lt -7v ____ -7
v gt -7
-10-9 -8 -7 -6 -5 -4 -3 -2 -1 0
11 21 1 __ 3 gt 3m - 2 2 __
3
21 1 __ 3 + 2 2 __
3 gt 3m - 2 2 __
3 + 2 2 __
3
24 gt 3m
24 ___ 3 gt 3m ___
3
8 gt m or m lt 8
0 1 4 5 72 3 6 8 9 10
12 a ___ -8
+ 15 gt 23
a ___ -8
+ 15 - 15 gt 23 - 15
a ___ -8
gt 8
-8 ( a ___ -8
) lt -8 ( 8 )
a lt -64
-70 -68 -66 -64 -62 -60
Copyright copy by Houghton Mifflin Harcourt 49 All rights reserved
13 f __ 2 - 22 lt 48
f __ 2 - 22 + 22 lt 48 + 22
f __ 2 lt 70
2 ( f __ 2 ) lt 2 ( 70 )
f lt 140
100 110 120 130 140 150
14 -25 + t __ 2 ge 50
-25 + 25 + t __ 2 ge 50 + 25
t __ 2 ge 75
2 ( t __ 2 ) ge 2 ( 75 )
t ge 150
130 140 150 160 170 180
15 10 + g ___
-9 gt 12
10 - 10 + g ___
-9 gt 12 - 10
g ___
-9 gt 2
-9 ( g ___
-9 ) lt -9 ( 2 )
g lt -18
-20 -18 -14 -12 -10-16
16 252 le -15y + 12
252 - 12 le -15y + 12 - 12
24 le - 15y
24 ____ -15
ge -15y
_____ -15
y le -16
-20 -18 -14 -12 -10-16
17 -36 ge -03a + 12
-36 - 12 ge -03a + 12 - 12
-48 ge -03a
-48 _____ -03
le -03a ______ -03
a ge 16
10 11 12 13 14 16 17 18 19 2015
18 80 - 2w ge 50
80 - 80 - 2w ge 50 - 80
- 2w ge -30
-2w ____ -2
le -30 ____ -2
w le 15
The width is a positive number no greater than
15 inches the possible widths in inches will be 10
11 12 13 14 and 15
19 Inequality 7n - 25 ge 65
7n - 25 ge 65
7n - 25 + 25 ge 65 + 25
7n ge 90
7n ___ 7 ge 90 ___
7
n ge 12 6 __ 7
Grace must wash at least 13 cars because n must
be a whole number
Focus on Higher Order Thinking
20 No Sample answer If x lt x - 1 then subtracting
x from both sides of the inequality 0 lt -1 That is
untrue so no value of x can be less than x - 1
21 a
10 3 42 5 6 7 8 9 10
b
10 3 42 5 6 7 8 9 10
c A number cannot simultaneously be less than 2
and greater than 7 Therefore there is no number
that satisfies both inequalities
d Consider the graph of x gt 2 and x lt 7
The solution includes all the numbers on the
number line so the solution set is all numbers
22 Sample answer Joseph might have reasoned that n
was first multiplied by 2 then increased by 5 to give
a result less than 13 Working backward he would
have subtracted 5 from 13 ( to get 8 ) then divided by
2 ( to get 4 ) giving n lt 4 Shawnee would have
followed these same steps but would have used a
variable and invers operations
MODULE 7
Ready to Go On
1 n + 7 lt -3
thinsp _ -7
_ -7
n lt -10
2 5p ge -30
5p
___ 5 ge -30 ____
5
p ge -6
3 14 lt k + 11
_ -11 _ -11
3 lt k
4 d ___ -3
le minus6
( -3 ) ( d ) ge ( -3 ) ( -6 )
d ge 18
Copyright copy by Houghton Mifflin Harcourt 50 All rights reserved
5 c - 25 le 25
_ +25 _ +25
c le 5
6 12 ge -3b
12 ___ -3
le -3b _____ -3
-4 le b
7 Let n be the number of minimum points Jose must
score 562 + n ge 650
Solve the inequality
562 + n ge 650
_ -562 _ -562
n ge 88
8 Let t be the number of minutes Lainey can descend
-20 - 20t ge -100
9 2s + 3 gt 15
_ -3 _ -3
2s gt 12
2s ___ 2
gt 12 ___ 2
s gt 6
10 - d ___ 12
- 6 lt 1
_ +6 _ +6
- d ___ 12
lt 7
12 ( - d ___ 12
) lt 12 ( 7 )
-d lt 84
d gt -84
11 -6w - 18 ge 36
_ +18 _ +18
thinsp-6w ge 54
-6w _____ -6
le 54 ___ -6
w le -9
12 z __ 4 + 22 le 38
_ -22 _ -22
z __ 4 le 16
4 ( z __ 4 ) le 4 ( 16 )
z le 64
13 b __ 9 - 34 lt -36
_ +34 _ +34
b __ 9 lt -2
9 ( b __ 9 ) lt 9 ( -2 )
b lt -18
14 -2p + 12 gt 8
-12 ____
-12 ____
-2p gt -4
-2p
____ -2 lt -4 ___
-2
p lt 2
15 Sample answer Look for key words or phrases
that indicate inequality such as ldquogreater thanrdquo
ldquoless thanrdquo ldquoat mostrdquo or ldquoat leastrdquo
Copyright copy by Houghton Mifflin Harcourt 51 All rights reserved
MODULE 8 Modeling Geometric Figures
Are You Ready
1 3x + 4 = 10
3x + 4 - 4 =10 - 4
3x = 6
3x ___ 3 = 6 __
3
x = 2
2 5x - 11 = 34
5x - 11 + 11 = 34 + 11
5x = 45
5x ___ 5 = 45 ___
5
x = 9
3 -2x + 5 = -9
-2x + 5 - 5 = -9 - 5
-2x = -14
-2x ____ -2
= -14 ____ -2
x = 7
4 -11 = 8x + 13
-11 - 13 = 8x + 13 - 13
-24 = 8x
-24 ____ 8 = 8x ___
8
-3 = x
5 4x - 7 = -27
4x - 7 + 7 = -27 + 7
4x = -20
4x ___ 4 = -20 ____
4
x = -5
6 1 __ 2 x + 16 = 39
1 __ 2 x + 16 - 16 = 39 - 16
1 __ 2 x = 23
( 2 ) 1 __ 2 x = ( 2 ) 23
x = 46
7 12 = 2x - 16
12 + 16 = 2x - 16 + 16
28 = 2x
28 ___ 2 = 2x ___
2
14 = x
8 5x - 15 = -65
5x - 15 + 15 = -65 + 15
5x = -50
5x ___ 5 = -50 ____
5
x = -10
9 x __ 5 = 18 ___
30
x times 30 = 5 times 18
30x = 90
30x ____ 30
= 90 ___ 30
x = 3
10 x ___ 12
= 24 ___ 36
x times 36 = 12 times 24
36x = 288
36x ____ 36
= 288 ____ 36
x = 8
11 3 __ 9 = x __
3
3 times 3 = 9 times x
9 = 9x
9 __ 9 = 9x ___
9
1 = x
12 14 ___ 15
= x ___ 75
14 times 75 = 15 times x
1050 = 15x
1050 _____ 15
= 15x ____ 15
70 = x
13 8 __ x = 14 ___ 7
8 times 7 = x times 14
56 = 14x
56 ___ 14
= 14x ____ 14
4 = x
14 14 ___ x = 2 __ 5
14 times 5 = x times 2
70 = 2x
70 ___ 2 = 2x ___
2
35 = x
15 5 __ 6 = x ___
15
5 times 15 = 6 times x
75 = 6x
75 ___ 6 = 6x ___
6
125 = x
Solutions KeyGeometry
UNIT
4
Copyright copy by Houghton Mifflin Harcourt 52 All rights reserved
16 81 ___ 33
= x ____ 55
81 times 55 = 33 times x
4455 = 33x
4455 _____ 33
= 33x ____ 33
135 = x
LESSON 81
Your Turn
6 Length 132 in times 5 ft ____ 3 in
= 22 ft
Width 6 in times 5 ft ____ 3 in
= 10 ft
Area 10 ft ( 22 ft ) = 220 square feet
Guided Practice
1
Blueprint
length (in)3 6 9 12 15 18
Actual
length (ft)5 10 15 20 25 30
a The wall is 30 feet long
b 25 ft times 3 in ____ 5 ft
= 15 in
2 The width is 7 in times 4 ft ____ 2 in
= 14 ft and the length is
14 in times 4 ft ____ 2 in
= 28 ft and the area is
28 ft ( 14 ft ) = 392 square feet
3 Length 10 cm times 5 m _____ 2 cm
= 25 m
Width 6 cm times 5 m _____ 2 cm
= 15 m
Area 25 m ( 15 m ) = 375 square meters
4 a
b Length is 36 m and width is 24 m using both
scales
5 If the scale drawing is complete and accurate you
can use it to find any length or area of the object of
the drawing
Independent Practice
6 a 2 in times 40 cm ______ 1 in
= 80 cm
15 in times 40 cm ______ 1 in
= 60 cm
The dimensions of the painting are 80 cm by 60 cm
b 80 cm times 60 cm = 4800 c m 2
c 80 cm times 1 in _______ 254 cm
asymp 315 in
60 cm times 1 in _______ 254 cm
asymp 236 in
The dimensions of the painting are approximately
315 in by 236 in
d 315 in times 236 in asymp 743 i n 2
7 120 ft times 1 unit _____ 5 ft
= 24 units
75 ft times 1 unit _____ 5 ft
= 15 units
The dimensions of the drawing are 24 units by
15 units
8 Sample answer 2 in6 ft 1 in3 ft and 1 in1 yd
9 Because the scale is 10 cm1 mm and because
10 cm is longer than 1 mm the drawing will be
larger
10 a Let r represent the scale
54 ft times r = 810 m
r = 810 m ______ 54 ft
r = 150 m ______ 1 ft
The scale is 1 ft = 150 m
b 54 ft times 12 in _____ 1 ft
= 648 in
Let b represent the number of tiny bricks
b = 648 in times 1 brick ______ 04 in
b = 162 bricks
The model is 162 tiny bricks tall
11 a Let h represent the height of the model
h = 30 ft times 126 cm _______ 1 ft
h = 378 cm
Let n represent the number of toothpicks
n = 378 cm times 1 toothpick
_________ 63 cm
n = 6 toothpicks
The model will be 6 toothpicks tall
b 378 cm times 1 swab ______ 76 cm
asymp 5 swabs
The model will be about 5 cotton swabs tall
Focus on Higher Order Thinking
12 If the area of the scale drawing is 100 square cm
then one side is 10 cm Let s represent the side
length of the actual floor
s = 10 cm times 2 ft _____ 1 cm
s = 20 ft
So the area is 20 ft(20 ft) = 400 ft 2
The ratio of areas is 100 square cm 400 square feet
or 1 square cm 4 square feet
Copyright copy by Houghton Mifflin Harcourt 53 All rights reserved
13 Decide on the new scale yoursquod like to use Then find
the ratio between the old scale and the new scale
and redraw the scale drawing accordingly For
example the ratio could be 13 In that case you
would redraw the dimensions at three times the
original size
14 Sample answer 1 __ 4 in 8 ft 40 ft by 24 feet 960 f t
2
LESSON 82
Guided Practice
1 The two angles 45deg and a right angle or 90deg with
the included side 8 cm determine the point at which
the sides meet so a unique triangle is formed
2 The sum of the measures of the two short sides
4 + 3 = 7 The sum is less than the measure of the
long side 11 so no triangle is formed
3 The two angles 40deg and 30deg with the included side
7 cm determine the point at which the sides meet
so a unique triangle is formed
4 The sum of the measures of the two short sides
6 + 7 = 13 The sum is greater than the measure of
the long side 12 so a unique triangle is formed
5 Sample answer Segments with lengths of 5 in
5 in and 100 in could not be used to form a
triangle
Independent Practice
6 A figure with side lengths of 3 centimeters and 6
centimeters and an included angle of 120deg deter-
mine the length of the third side of a triangle and so
produce a unique triangle
6 cm
3 cm120˚
7 The side lengths proposed are 15 ft 21 ft and 37 ft
The sum of the measures of the two shorter sides
15 + 21 = 36 So the sum is less than the measure
of the long side 37 No such triangle can be created
8 The three angle measures can be used to form
more than one triangle The sign and the scale
drawing are two different-sized triangles with the
same angle measures
Focus on Higher Order Thinking
9 More than one triangle can be formed Two triangles
can be created by connecting the top of the 2-in
segment with the dashed line once in each spot
where the arc intersects the dashed line The
triangles are different but both have side lengths of
2 in and 1 1 __ 2 in and a 45deg angle not included
between them
10 The third side has a length of 15 in The third side
must be congruent to one of the other two sides
because the triangle is isosceles The third side
cannot measure 6 in because 6 + 6 is not greater
than 15 So the third side must measure 15 in
LESSON 83
Guided Practice
1 triangle or equilateral triangle
2 rectangle
3 triangle
4 rainbow-shaped curve
5 Sample answer Draw the figure and the plane
Independent Practice
6 Sample answer A horizontal plane results in cross
section that is a circle A plane slanted between
horizontal and vertical results in an oval cross
section A vertical plane through the cylinder results
in a rectangle A vertical plane along an edge of the
cylinder results in a line cross section
7 You would see circles or ovals with a cone but not
with a pyramid or prism
Focus on Higher Order Thinking
8 The plane would pass through the cube on a
diagonal from the top to the bottom of the cube
9 a It is a circle with a radius of 12 in
b The cross sections will still be circles but their
radii will decrease as the plane moves away from
the spherersquos center
10 The dimensions of two faces are 12 in by 8 in two
are 8 in by 5 in and two are 12 in by 5 in the
volume is 480 in 3
11 Sample answer If you think of a building shaped like
a rectangular prism you can think of horizontal
planes slicing the prism to form the different floors
Copyright copy by Houghton Mifflin Harcourt 54 All rights reserved
LESSON 84
Your Turn
5 Supplementary angles sum to 180deg Sample answer angFGA and angAGC
6 Vertical angles are opposite angles formed by two
intersecting lines
Sample answer angFGE and angBGC
7 Adjacent angles are angles that share a vertex and
one side but do not overlap Sample answer
mangFGD and mangDGC
8 Complementary angles are two angles whose
measures have a sum of 90deg Sample answer
mangBGC and mangCGD
9 Because mangFGE = 35deg and angFGE and angBGC are
vertical angles that means mangBGC = 35deg also
Because lines _
BE and _
AD intersect at right angles
mangBGD = 90deg so mangBGC + mangCGD = 90deg which means
mangBGC + mangCGD = 90deg 35deg + x = 90deg 35deg minus 35deg + x = 90deg minus 35deg x = 55deg
mangCGD = 55deg
10 angJML and angLMN are supplementary so their
measures sum to 180deg mangJML + mangLMN = 180deg 3x + 54deg = 180deg 3x + 54deg - 54deg = 180deg - 54deg 3x = 126deg
3x ___ 3 = 126deg ____
3
x = 42deg
mangJML = 3x = 3 ( 42deg ) = 126deg
11 Sample answer You can stop at the solution step
where you find the value of 3x because the measure
of angJML is equal to 3x
Guided Practice
1 angUWV and angUWZ are complementary angles
2 angUWV and angVWX are adjacent angles
3 angAGB and angDGE are vertical angles
so mangDGE = 30deg
4 mangCGD + mangDGE + mangEGF = 180deg 50deg + 30deg + 2x = 180deg 80deg + 2x = 180deg 2x = 100deg mangEFG = 2x = 100deg
5 mangMNQ + mangQNP = 90deg 3x - 13deg + 58deg = 90deg so 3x + 45deg = 90degThen 3x = 45deg and x = 15deg mangMNQ = 3x - 13deg = 3 ( 15deg ) - 13deg = 45deg - 13deg = 32deg
6 Sample answer Let mangS = x Write and solve an
equation ( x + 3x = 180deg ) to find x then multiply the
value by 3
Independent Practice
7 Sample answer angSUR and angQUR are adjacent
They share a vertex and a side
8 Sample answer angSUR and angQUP
9 Sample answer angTUS and angQUN
10 mangQUR = 139deg Sample answer angSUR and angSUP
are supplementary so mangSUP = 180deg - 41deg = 139deg angSUP and angQUR are vertical angles so they are
congruent and mangQUR = mangSUP = 139deg
11 mangRUQ is greater Sample answer angSUR and
angNUR are complementary so
mangNUR = 90deg - 41deg = 49deg mangTUR = 41deg + 90deg which is less than
mangRUQ = 49deg + 90deg
12 Because angKMI and angHMG are vertical angles their
measures are equal
mangKMI = mangHMG
84 = 4x
84 ___ 4 = 4x ___
4
x = 21deg
13 Because angKMH and angKMI are supplementary
angles the sum of their measures is 180deg mangKMH + mangKMI = 180deg x + 84 = 180
x + 84 - 84 = 180 - 84
x = 96
mangKMH = 96deg
14 Because angCBE and angEBF are supplementary
angles the sum of their measures is 180deg mangCBE + mangEBF = 180deg x + 62 = 180
x + 62 - 62 = 180 - 62
x = 118
mangCBE = 118deg
15 Because angABF and angFBE are complementary
angles the sum of their measures is 90deg mangABF + mangFBE = 90deg x + 62 = 90
x + 62 - 62 = 90 - 62
x = 28
mangABF = 28deg
16 Because angCBA and angABF are supplementary
angles the sum of their measures is 180deg mangABF = 28deg so
mangCBA + mangABF = 180deg x + 28 = 180 - 28
x + 28 - 28 = 152
mangCBA = 152deg
Copyright copy by Houghton Mifflin Harcourt 55 All rights reserved
17 If the two angles are complementary the sum of
their angles is 90degmangA + mangB = 90deg ( x + 4deg ) + x = 90deg 2x + 4deg = 90deg _ -4deg _ -4deg 2x = 86deg
2x ___ 2 = 86deg ___
2
x = 43degBecause x = mangB then mangB = 43deg and
mangA = 43deg + 4deg so mangA = 47deg
18 If the two angles are supplementary the sum of their
angles is 180degmangD + mangE = 180deg 5x + x = 180deg 6x = 180deg
6x ___ 6 = 180deg ____
6
x = 30degBecause x = mangE then mangE = 30deg and
mangD = 30deg x 5 so mangD = 150deg
19 If the two angles are complementary the sum of
their angles is 90deg When angles are divided into
minutes and seconds one apostrophe signifies a
minute and two apostrophes signifies a second
mangJ + mangK = 90deg0000
48deg268+ mangK = 90deg0000
_ -48deg268 _ -48deg268
mangK = 41deg3352
mangK = 41deg3352 or mangK = 41 degrees
33 minutes 52 seconds
Focus on Higher Order Thinking
20 Yes a parking lot can be built because the measure
of angle K is 180deg - ( 50deg + 90deg ) or 40deg which is
greater than 38deg
21 Disagree the sum of the measures of a pair of
complementary angles is 90deg So the measure of
each angle must be less than 90deg 119deg gt 90deg
22 a The sum of mangA and its complement will be 90deg Let x represent the complement
mangA + x = 90deg 77deg + x = 90deg _ -77deg = _ -77deg x = 13deg The complement of mangA has a measure of 13deg
and a complement of a complement of mangA
would have an angle equal to mangA or 77deg b A complement of a complement of an angle has
the same measure of the angle itself Let xdeg be
the measure of an angle The measure of a
complement of the angle is ( 90 - xdeg ) A complement of that angle has a measure of
( 90 - ( 90 - xdeg ) ) = ( 90 - 90 + xdeg ) = xdeg
MODULE 8
Ready to Go On
1
Living
roomKitchen Office Bedroom Bedroom Bathroom
Actual
ℓ times w ( ft ) 16 times 20 12 times 12 8 times 12 20 times 12 12 times 12 6 times 8
Blueprint
ℓ times w ( in ) 4 times 5 3 times 3 2 times 3 5 times 3 3 times 3 15 times 2
2 No The side lengths proposed are 8 cm 4 cm and
12 cm The sum of the measures of the two shorter
sides 4 + 8 = 12 So no such triangle can be
created
3 The longest side could be 15 cm because 20 cm is
too long given the lengths of the other sides
4 A circle is a possible cross section of a sphere
A point is another
5 A circle rectangle oval and line are possible cross
sections of a cylinder
6 mangBGC and mangFGE are vertical angles so
mangFGE = 50deg
7 If the two angles are complementary the sum of
their angles is 90deg mangS + mangY = 90deg
( 2 ( mangY ) - 30deg ) + mangY = 90deg 3 ( mangY ) - 30deg = 90deg _ +30deg = _ +30deg 3 ( mangY ) = 120deg
3 ( mangY ) ________ 3 = 120deg ____
3
mangY = 40deg
mangY = 40deg
8 Sample answer You can use scale drawings to plan
rooms or gardens
Copyright copy by Houghton Mifflin Harcourt 56 All rights reserved
MODULE 9 Circumference Area and Volume
Are You Ready
1 416
_ times 13
1248
_ +thinsp4160
5408
5408
2 647
_ times thinsp04
2588
2588
3 705
_ times thinsp94
2820
_ +thinsp63450
66270
6627
4 256
_ timesthinsp049
2304
_ +thinsp10240
12544
12544
5 1 __ 2 ( 14 ) ( 10 )
7 ( 10 )
70 i n 2
6 ( 35 ) ( 35 )
1225 ft 2
7 ( 8 1 __ 2 ) ( 6 )
17 ___ 1 2 sdot 6 3 __
1
51 i n 2
8 1 __ 2 ( 125 ) ( 24 )
1 __ 2 ( 24 ) ( 125 )
( 12 ) ( 125 )
15 m 2
LESSON 91
Your Turn
3 d = 11 cm
C = πd
C asymp 314 ( 11 )
C asymp 3454
The circumference is about 3454 cm
6 C = πd
44 asymp 314d
44 ____ 314
asymp d
d asymp 1401 yards
Divide the diameter of the garden by the digging
rate
1401 divide 7 = 2001
It takes Lars about 2 hours to dig across the garden
Guided Practice
1 d = 9 in
C asymp 314 ( 9 )
C asymp 2826 in
2 r = 7 cm
C = 2πr
C asymp 2 ( 22 ___ 7 ) ( 7 )
C asymp 44 cm
3 d = 25 m
C = πd
C asymp 314 ( 25 )
C asymp 785 m
4 r = 48 yd
C = 2πr
C asymp 2 ( 314 ) ( 48 )
C asymp 3014 yd
5 r = 75 in
C = 2πr
C asymp 2 ( 314 ) ( 75 )
C asymp 471 in
6 Find the diameter
C = πd
66 asymp 314d
66 ____ 314
asymp 314d _____ 314
21 asymp d
Find the cost
Carlos needs 21 + 4 = 25 feet of rope
25 times $045 = $1125
Carlos will pay $1125 for the rope
7 Because C = π yd and C = πd d = 1 yd then
r = 05 yd
d = 1 yd
8 Because C = 788 ft and C = 2πr
2πr = 788
2πr ___ 2π
= 788 ____ 2π
r asymp 788 _______ 2 ( 314 )
r asymp 1255 ft
d = 2r asymp 2 ( 1255 ft )
d asymp 2510 ft
9 d = 2r so r = d __ 2 asymp 34 ___
2
r asymp 17 in
C = πd asymp 314 ( 34 )
C = 1068 in
Copyright copy by Houghton Mifflin Harcourt 57 All rights reserved
10 Use the formula C = πd and substitute
314 for π and 13 for the diameter
Independent Practice
11 d = 59 ft
C = πd
C asymp 314 ( 59 )
C asymp 1853 ft
12 r = 56 cm
C = 2πr
C asymp 2 ( 22 ___ 7 ) ( 56 )
C asymp 352 cm
13 d = 35 in
C = πd
C asymp ( 22 ___ 7 ) ( 35 )
C asymp 110 in
14 Sample answer In exercises 12 and 13 the radius
or diameter is a multiple of 7
15 r = 94 ft
d = 2r = 2 ( 94 )
d = 188 ft
C = πd
C asymp 314 ( 188 )
C asymp 590 ft
16 d = 475 in
r = d __ 2 = 475 ____
2
r = 2375 in
C = πd
C asymp 314 ( 475 )
C asymp 14915 in
17 d = 18 in
r = d __ 2 = 18 ___
2
r = 9 in
C = πd
C asymp 314 ( 18 )
C asymp 5652 in
18 r = 15 ft
C = 2πr
C asymp 2 ( 314 ) ( 15 ) = 942 ft
The cost for edging is C times $075 per foot
so ( 942 ) ( 075 ) = 7065 or about $707
19 C = πd
C asymp ( 22 ___ 7 ) ( 63 )
C asymp 198 ft
The distance traveled is 12 times the
circumference of the Ferris wheel so
distance = 12 ( 198 ) or about 2376 ft
20 C = πd asymp 314 ( 2 )
C asymp 628 ft
Converting km to ft
2 km sdot ( 3280 ft _______
1 km ) = 6560 ft
6560 ft
_______ 628 ft
= 104459
The wheel makes about 1045 revolutions
21 The distance your friend walks is half the
circumference of the pond
1 __ 2 C = 1 __
2 πd asymp 1 __
2 sdot 314 ( 025 ) = 03925
Your friend walks approximately 03925 mi
The difference is 03925 - 025 = 01425
Your friend walks about 014 mi farther
22 Capitol Rotunda Dimensions
Height 180 ft
Circumference 3015 ft
Radius r = C ___ 2π asymp 3015
_______ 2 ( 314 )
asymp 48 ft
Diameter d = 2r = 2 ( 48 ) = 96 ft
Focus on Higher Order Thinking
23 The length of the fence is half the circumference
plus the diameter
1 __ 2 C = 1 __
2 πd asymp 1 __
2 sdot 314 ( 30 ) = 471
The total distance is 471 + 30 = 771 ft
The total cost is the length of fence times the cost
per linear foot
( 771 ft ) ( $925 _____
ft ) = $71318
It will cost about $71318
24 The circumference of the patio is
C = πd asymp 314 ( 18 ) = 5652 ft
Converting the length of one strand of lights from
inches to feet
( 54 in ) ( 1 ft _____ 12 in
) = 45 ft
To find the number of strands of lights divide the
circumference by the length of one strand
5652 ft _______ 45 ft
= 1256
Because Sam cannot buy a fraction of a strand he
must buy 13 strands
25 The distance is the difference in the circumferences
C inner
= πd asymp 314 ( 150 ) = 471 ft
The outer diameter is 150 ft + 2 ( 2 ft ) = 154 ft
C outer
= πd asymp 314 ( 154 ) = 48356 ft
The difference is 48356 - 471 = 1256 ft
It is about 1256 ft farther
26 No The circumference of the larger gear is about
πd asymp 314 ( 4 ) = 1256 inches The circumference of
the smaller gear is about πd asymp 314 ( 2 ) = 628
inches So the circumference of the larger gear is
628 inches more than the circumference of the
smaller gear
Copyright copy by Houghton Mifflin Harcourt 58 All rights reserved
27 Pool B about 057 m or 184 ft Sample answer
24 feet asymp 732 m so the diameter of Pool B is
greater and the circumference is greater
314 ( 75 ) - 314 ( 732 ) = 314 ( 018 ) asymp 057
057 m asymp 187 ft
LESSON 92
Your Turn
4 A = π r 2 A = π ( 10 ) 2
A asymp 314 ( 10 ) 2
A asymp 314 sdot 100
A asymp 314 f t 2
Guided Practice
1 r = d __ 2 = 14 ___
2 = 7 m
A = π r 2 A = π ( 7 ) 2
A asymp 314 ( 7 ) 2
A asymp 314 sdot 49
A asymp 1539 m 2
2 A = π r 2 A = π ( 12 ) 2
A asymp 314 ( 12 ) 2
A asymp 314 sdot 144
A asymp 4522 m m 2
3 r = d __ 2 = 20 ___
2 = 10 yd
A = π r 2 A = π ( 10 ) 2
A asymp 314 ( 10 ) 2
A asymp 314 sdot 100
A asymp 314 y d 2
4 A = π r 2 A = π ( 8 ) 2
A asymp 314 ( 8 ) 2
A asymp 314 sdot 64
A asymp 20096 i n 2
5 r = d __ 2 = 12 ___
2 = 6 cm
A = π r 2 A = π ( 6 ) 2
A asymp 314 ( 6 ) 2
A asymp 314 sdot 36
A asymp 11304 c m 2
6 r = d __ 2 = 13 ___
2 = 65 in
A = π r 2 A = π ( 65 ) 2
A asymp 314 ( 65 ) 2
A asymp 314 sdot 4225
A asymp 13267 i n 2
7 C = 4π = 2πr
4π ___ 2π
= 2πr ___ 2π
r = 2
A = π r 2 A = π ( 2 ) 2
A = 4π square units
8 C = 12π = 2πr
12π ____ 2π
= 2πr ___ 2π
r = 6
A = π r 2 A = π ( 6 ) 2
A = 36π square units
9 C = π __ 2 = 2πr
π __ 2 divide 2π = 2πr ___
2π
π __ 2 sdot 1 ___
2π = r
1 __ 4 = r
A = π r 2
A = π ( 1 __ 4 ) 2 = π ( 1 ___
16 )
A = π ___ 16
square units
10 A = π r 2 = 64π
π r 2 ___ π = 64π ____ π
r 2 = 64
r = 8
C = 2πr
= 2π ( 8 )
=16π yd
11 A = π r 2
Independent Practice
12 r = d __ 2 = 10 ___
2 = 5 in
A = π r 2 A = π ( 5 ) 2
A asymp 314 ( 5 ) 2
A asymp 314 sdot 25
A asymp 785 i n 2
13 A = π r 2 A = π ( 16 ) 2
A asymp 314 ( 16 ) 2
A asymp 314 sdot 256
A asymp 80384 c m 2
14 The area of the window is half the area of a circle of
diameter 36 in
r = d __ 2 = 36 ___
2 = 18 in
A semicircle
= 1 __ 2 π r 2
A semicircle
= 1 __ 2 π ( 18 ) 2
A semicircle
asymp 1 __ 2 ( 314 ) ( 18 ) 2
A semicircle
asymp 05 sdot 314 sdot 324
A asymp 50868 i n 2
Copyright copy by Houghton Mifflin Harcourt 59 All rights reserved
15 If the point ( 3 0 ) lies on the circle and the origin is
its center the radius of the circle is 3 units
A = π r 2 A = π ( 3 ) 2
A asymp 314 ( 3 ) 2
A asymp 314 sdot 9A asymp 2826 square units
16 The difference in areas is given by
A r = 75 mi
- A r = 50 mi
π ( 75 ) 2 - π ( 50 ) 2
= π ( 7 5 2 minus 5 0 2 ) = π ( 5625 minus 2500 ) = π ( 3125 ) asymp 98125
The area of the relayed signal is about 9813 mi 2
greater
17 The area of the field which is not reached by the
sprinkler is the area of the field minus the area
reached by the sprinkler or s 2 minus π r 2 where
s = 12 m and r is the radius of the circular area The
diameter of the circle is equal to a side of the field
12 m so the radius is 12 ___ 2 = 6 m So
s 2 minus π r 2 = 1 2 2 minus π ( 6 ) 2
= 144 minus π ( 36 )
asymp 144 minus 11304 = 3096
The area not reached by the sprinkler is
approximately 3096 m 2
18 No the area of the regular pancake is 4π in 2 and the
area of the silver dollar pancake is π in 2 so the area
of the regular pancake is 4 times the area of the
silver dollar pancake
19 No the top of the large cake has an area 9 times
that of the small cake The area of the top of the
large cake is 144π in 2 and that of the small cake is
16π in 2
20 Sample answer First find the radius of the circle by
using the formula C = 2πr Then substitute the
radius into the formula for the area of a circle
21 The 18-inch pizza is a better deal because it costs
about $20
_____ π ( 9 ) 2
asymp $008 or 8 cents per square inch
while the 12-inch pizza costs about $10
_____ π ( 6 ) 2
asymp $009
or 9 cents per square inch
22 a Because the bear can walk at a rate of 2 miles
per hour and was last seen 4 hours ago the
radius of the area where the bear could be found
is given by ( 2 miles per hour ) ( 4 hours ) = 8 miles
A = π r 2 = π ( 8 ) 2
= π ( 64 )
asymp 20096
The searchers must cover an area of about
201 mi 2
b The additional area is the difference in areas of
circles with radii ( 2 miles per hour ) ( 5 hours )
= 10 miles and the original 8 miles
A new
minus A old
= π ( 10 ) 2 - π ( 8 ) 2
= π ( 1 0 2 - 8 2 ) = π ( 100 - 64 )
= π ( 36 ) asymp 11304
The searchers would have to cover about 113 mi 2
more area
Focus on Higher Order Thinking
23 No the combined area is 2π r 2 while the area of a
circle with twice the radius is 4π r 2
24 The area is multiplied by a factor of n 2
25 To find the part that is the bullrsquos-eye take the ratio of
the area of the bullrsquos-eye to that of the whole target
The radius of the bullrsquos-eye is 3 __ 2 = 15 in and
the radius of the whole target is 15 ___ 2 = 75 in
A
bullrsquos-eye ________
A whole target
=
π ( 15 ) 2 ______
π ( 75 ) 2
= ( 15 ) 2
_____ ( 75 ) 2
= 225 _____ 5625
= 004
The bullrsquos-eye is 004 or 4 of the whole target
LESSON 93
Your Turn
2 The figure can be separated into a rectangle and
two right triangles
The dimensions of the large rectangle are
length = 8 + 3 = 11 ft width = 4 ft
The dimensions of the two small triangles are
base = 3 ft height = 2 ft ( upper triangle ) base = 3 ft height = 3 ft ( lower triangle ) The area of the rectangle is
A = ℓw = 11 sdot 4 = 44 f t 2
The area of the upper triangle is
A = 1 __ 2 bh = 1 __
2 sdot 3 sdot 2 = 3 f t 2
The area of the lower triangle is
A = 1 __ 2 bh = 1 __
2 sdot 3 sdot 3 = 45 f t 2
Therefore the total area of the figure is
44 + 3 + 45 = 515 f t 2
3 The figure can be separated into a square and a
semicircle
Each side of the square is equal to 10 m
The radius of the semicircle is half the diameter
or 10 ___ 2 = 5 m
The area of the square is
A = s 2 = 1 0 2 = 100 m 2
The area of the semicircle is
A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 5 ) 2
A asymp 1 __ 2 sdot 314 sdot 25
A asymp 3925 m 2
Therefore the approximate total area of the figure is
100 + 3925 = 13925 m 2
Copyright copy by Houghton Mifflin Harcourt 60 All rights reserved
4 The composite figure is made up of a rectangle and two
semicircles which can be combined to form one circle
The dimensions of the rectangle are
length = 5 ft width = 4 ft
The diameter of the circle is 4 ft so the radius is
4 __ 2 = 2 ft
The area of the rectangle is
A = ℓw = 5 sdot 4 = 20 f t 2
The area of the circle is
A = π r 2 A asymp 314 sdot ( 2 ) 2
A asymp 314 sdot 4A asymp 1256 f t 2
The approximate total area is the sum of these
two areas
20 + 1256 = 3256 f t 2
Because the glass costs $28 per square foot
multiply the total area by the cost per square foot
( 3256 f t 2 ) ( $28 ____
f t 2 ) = $91168
It will cost about $91168 to replace the glass
Guided Practice
1 Separate the figure into a triangle a rectangle and
a parallelogram
Find the area of each figure
For triangle A = 1 __ 2 bh = 1 __
2 ( 4 ) ( 2 ) = 4
For rectangle A = ℓw = ( 5 ) ( 3 ) = 15
For parallelogram A = bh = ( 5 ) ( 3 ) = 15
Triangle 4 cm 2 rectangle 15 cm
2 parallelogram
15 cm 2
Step 3 Find the area of the composite figure
4 + 15 + 15 = 34 cm 2
The area of the irregular shape is 34 cm 2
2 Method 1
A 1 = ℓw A
2 = ℓw
= 12 sdot 9 = 20 sdot 9 = 108 = 180
Total area = 288 c m 2
Method 2
A 1 = ℓw A
2 = ℓw
= 9 sdot 8 = 12 sdot 8 = 72 = 216
Total area = 288 c m 2
3 Separate the figure into a trapezoid with h = 5 ft
b 1 = 7 ft and b 2 = 4 ft and a parallelogram with
base = 4 ft and height = 4 ft
For trapezoid A = 1 __ 2 h ( b
1 + b
2 )
A = 1 __ 2 ( 5 ) ( 7 + 4 )
A = 1 __ 2 ( 5 ) ( 11 ) = 275 f t 2
For parallelogram A = bh = ( 4 ) ( 4 ) = 16 f t 2
Find the area of the composite figure
275 + 16 = 435 ft 2
Multiply the total area by the cost per square foot to
find the cost
( 435 f t 2 ) ( $225 _____
f t 2 ) = $9788
4 The first step is separating the composite figure into
simpler figures
Independent Practice
5 Area of square A = s 2 = 2 6 2 = 676 i n 2
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 13 ) 2
A asymp 1 __ 2 sdot 314 sdot 169
A asymp 26533 i n 2
The approximate total area is the sum
676 + 26533 = 94133 in 2
6 a The floor of the closet is a composite of a
rectangle with length = 10 ft and width = 4 ft and
a triangle with base = 6 ft and height = 3 + 4 = 7 ft
Area of rectangle A = ℓw = 10 sdot 4 = 40 f t 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 6 sdot 7
A = 1 __ 2 sdot 42
A = 21 f t 2
The total area is the sum
40 + 21 = 61 f t 2
b The cost is the area multiplied by the cost per
square foot
( 61 f t 2 ) ( $250 _____
f t 2 ) = $15250
7
O 42-2-4
2
-4
y
A (-2 4) B (0 4)
C (2 1)D (5 1)
E (5 -2)F (-2 -2)
The area can be thought of as a composite of a
trapezoid and a rectangle
For trapezoid Let b 1 of the trapezoid be the
segment from the point ( -2 1 ) point C with length
4 units b 2 be from point A to point B with length
2 units and height equal to 3 units
For rectangle The corners of the rectangle are
( -2 1 ) D E and F Let the length of the rectangle
be 7 units and the width be 3 units
Area of trapezoid
A = 1 __ 2 h ( b
1 + b
2 )
A = 1 __ 2 ( 3 ) ( 4 + 2 )
A = 1 __ 2 ( 3 ) ( 6 ) = 9 square units
Copyright copy by Houghton Mifflin Harcourt 61 All rights reserved
Area of rectangle A = ℓw
A = 7 sdot 3 A = 21 square units
The total area is the sum
9 + 21 = 30 square units
8 The field is a composite of a square with side = 8 m
a triangle with base = 8 m and height = 8 m and a
quarter of a circle with radius = 8 m
Area of square A = s 2 = 8 2 = 64 m 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 8 sdot 8
A = 1 __ 2 sdot 64
A = 32 m 2
Area of quarter circle A = 1 __ 4 π r 2
A asymp 1 __ 4 sdot 314 sdot ( 8 ) 2
A asymp 1 __ 4 sdot 314 sdot 64
A asymp 5024 f t 2
The approximate total area is the sum
64 + 32 + 5024 = 14624 m 2
9 The bookmark is a composite of a rectangle with
length = 12 cm and width = 4 cm and two
semicircles which combine to form a full circle with
diameter = 4 cm so radius = 4 __ 2 = 2 cm
Area of rectangle A = ℓw = 12 sdot 4 = 48 c m 2
Area of circle A = π r 2 A asymp 314 sdot ( 2 ) 2
A asymp 314 sdot 4 A asymp 1256 c m 2
The approximate total area is the sum
48 + 1256 = 6056 cm 2
10 The pennant is a composite of a rectangle with
length = 3 ft and width = 1 ft and a triangle with
base = 1 ft and height = 1 ft
Area of rectangle A = ℓw = 3 sdot 1 = 3 f t 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 1 sdot 1
A = 1 __ 2 sdot 1
A = 05 f t 2
The area of one pennant is the sum
3 + 05 = 35 ft 2
Alex is making 12 pennants so the total area of all
12 pennants is 12 sdot 35 = 42 ft 2
The cost for the pennants will be the total area times
the fabric cost per square foot
( 42 f t 2 ) ( $125 _____
f t 2 ) = $5250
11 The area of the square is the total area minus the
area of triangle
325 ft 2 - 75 ft 2 = 25 ft 2
The area of a square is A = s 2 so s 2 = 25 f t 2
Because 5 sdot 5 = 25 the length of each side of the
square is 5 ft
Focus on Higher Order Thinking
12 The area of the garden can be found from counting
squares there are 18 full squares and 4 half-squares
for a total of 20 square units Each square unit will
grow about 15 carrots So Christina will grow about
20 ( 15 ) or 300 carrots
13 To find the length of the three sides of the square
subtract the lengths of the two sides of the triangle
from the perimeter The total length of three sides of
the square is 56 - 20 = 36 in Divide by 3 to find
that the length of one side and the base of the
triangle is equal to 12 in The total area of the figure
is the area of the square plus the area of the
triangle
Area of square A = s 2 = 1 2 2 = 144 i n 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 12 sdot 8
A = 1 __ 2 sdot 96
A = 48 i n 2
The total area is the sum
144 + 48 = 192 in 2
14 Think of the scarf as a rectangle minus two
semicircles The rectangle has length = 28 in and
width = 15 in The circle has diameter = 15 in so
its radius is 15 ___ 2 = 75 in
Area of rectangle A = ℓw = 28 sdot 15 = 420 i n 2
Area of circle A = π r 2 A asymp 314 sdot ( 75 ) 2
A asymp 314 sdot 5625
A asymp 176625 i n 2
The total area is the difference
420 - 176625 = 243375 in 2 or 243 3 __
8 i n 2
15 a The window is a composite of a square and a
semicircle Because each square in the window
has an area of 100 in 2 the length of each side is
10 in So each side of the square portion of the
entire window has length 10 sdot 4 = 40 in The
diameter of the semicircle is also 40 in so
the radius is 40 ___ 2 = 20 in
Area of square A = s 2 = 4 0 2 = 1600 i n 2
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 20 ) 2
A asymp 1 __ 2 sdot 314 sdot 400
A asymp 628 i n 2
The approximate total area is the sum
1600 + 628 = 2228 in 2
Copyright copy by Houghton Mifflin Harcourt 62 All rights reserved
b The shade is a composite of a rectangle and
a semicircle The length of the rectangle is equal
to the length of one side of the square portion
of the window plus 2 sdot 4 inches for a total of
40 + 2 sdot 4 = 48 in
The height of the rectangular portion of the shade
is equal to 4 times the length of one side of the
square portion of the window plus 4 inches for a
total of 40 + 4 = 44 in
The diameter of the semicircle at the top is the
same as the length of the bottom of the shade
48 in so the radius = 48 ___ 2 = 24 in
Area of rectangle A = ℓw = 48 sdot 44 = 2112 i n 2
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 24 ) 2
A asymp 1 __ 2 sdot 314 sdot 576
A asymp 90432 i n 2
The approximate total area of the shade is
the sum
2112 + 90432 asymp 3016 in 2
LESSON 94
Your Turn
3 Find the area of a base
B = l times w
= 9 times 2
= 18 square inches
Find the perimeter of the base
P = 2 ( 9 ) + 2 ( 2 )
= 18 + 4 = 22 inches
Find the surface area
S = Ph + 2B
S = 22 ( 1 1 __ 2 ) + 2 ( 18 )
= 33 + 36
= 69
The surface area of the box is 69 square inches
4 Find the area of the base of the larger prism
B = times w
= 12 times 12
= 144 square inches
Find the perimeter of the base
P = 4 ( 12 )
= 48 inches
Find the surface area of the larger prism
S = Ph + 2B
S = 48 ( 12 ) + 2 ( 144 )
= 576 + 288
= 864 square inches
Find the area of the base of the smaller prism
B = l times w
= 8 times 8
= 64 square inches
Find the perimeter of the base
P = 4 ( 8 )
= 32 inches
Find the surface area of the smaller prism
S = Ph + 2B
S = 32 ( 8 ) + 2 ( 64 )
= 256 + 128
= 384 square inches
Add the surface areas of the two prisms and
subtract the areas not stained (the bottom of the
larger prism and the smaller prism and an equal
area of the top of the larger prism where the smaller
prism sits) Surface area = 864 + 384 - 144 - 64
- 64 = 976 The surface area of the part of the plant
stand that she will stain is 976 square inches
Guided Practice
1 Perimeter of base = 5 + 5 + 8 = 18
Perimeter of base = 18 ft
Height = 7 ft
Base area = 1 __ 2 ( 3 ) ( 8 ) = 12 ft 2
Surface area
S = ( 18 ft ) ( 7 ft ) + 2 ( 12 ft 2 ) = 150 ft 2
2 Find the area of a base of the cube
B = l times w
= 25 times 25
= 625 m 2
Find the perimeter of the base of the cube
P = 4 ( 25 )
= 10 m
Find the surface area of the cube
S = Ph + 2B
S = 10 ( 25 ) + 2 ( 625 )
= 25 + 125
= 375
Surface area of cube
S = 375 m 2
Find the area of a base of the rectangular prism
B = l times w
= 11 times 9
= 99 m 2
Find the perimeter of the base of the rectangular
prism
P = 2 ( 11 ) + 2 ( 9 )
= 22 + 18
= 40 m
Find the surface area of the rectangular prism
S = Ph + 2B
S = 40 ( 7 ) + 2 ( 99 )
= 280 + 198
= 478
Surface area of rectangular prism
S = 478 m 2
Find the overlapping area the bottom of the cube
A = ( 25 ) ( 25 ) = 625
Overlapping area A = 625 m 2
Surface area of composite figure
= 375 + 478 -2 ( 625 ) = 503 m 2
3 Find the surface area of each of the prisms that
make up the solid Add the surface areas and
subtract the areas of any parts that are not on the
surface
Copyright copy by Houghton Mifflin Harcourt 63 All rights reserved
Independent Practice
4 Find the area of a base
B = l times w
= 10 times 3
= 30 in 2
Find the perimeter of the base
P = 2 ( 10 ) + 2 ( 3 )
= 20 + 6
= 26 in
Find the surface area
S = Ph + 2B
S = 26 ( 4 ) + 2 ( 30 )
=104 + 60
= 164 in 2
She needs 164 in 2 of wrapping paper
5 Find the area of the base
B = l times w
= 20 times 15
= 300 cm 2
Find the perimeter of the base
P = 2 ( 20 ) + 2 ( 15 )
= 40 + 30
= 70 cm
Find the surface area of the box
S = Ph + 2B
S = 70 ( 9 ) + 2 ( 300 )
= 630 + 600
= 1230 cm 2
Find the surface area of the top and sides
1230 - 300 = 930 cm 2
Find the area of a glass tile
Area of tile = 5 times 5 = 25 mm 2
Convert cm 2 to mm
2
930 cm 2 times 100 mm
2 ________
1 cm 2 = 93000 mm
2
Find the number of tiles needed
93000 divide 25 = 3720
3720 tiles are needed
6 Find the area of the L-shaped base
Area of L-shape = 2 times 1 + 3 times 1
= 2 + 3 = 5 in 2
Find the perimeter of the L-shaped base
Perimeter = 3 + 3 + 1 + 2 + 2 + 1
= 12 in
Find the surface area
S = Ph + 2B
S = 12 ( 3 ) + 2 ( 5 )
= 36 + 10
= 46 in 2
The surface area of each brace is 46 in 2
7 Find the area of the triangular prism
Perimeter = 25 + 25 + 3 = 8 ft
Base area = 1 __ 2 ( 2 ) ( 3 ) = 3 ft 2
Surface area = Ph + 2B
= 8 ( 4 ) + 2 ( 3 )
= 32 + 6 = 38 ft 2
Find the area of the rectangular prism
Perimeter = 2 ( 3 ) + 2 ( 4 ) = 14 ft
Base area = 3 times 4 = 12 ft 2
Surface area = Ph + 2B
= 14 ( 2 ) + 2 ( 12 )
= 28 + 24 = 52 ft 2
Add the surface areas of the two prisms and
subtract the parts not on the surface
Surface area = 38 + 52 - 12 - 12 = 66 ft 2
The total surface area of the doghouse is 66 ft 2
8 Treat the figure as ( 1 ) a composite of two triangular
prisms and one rectangular prism or ( 2 ) a prism
with a base that is a trapezoid
9 Find the area of the trapezoid base
Area of trapezoid = 1 __ 2 ( b
1 + b
2 ) h
1 __ 2 ( 16 + 48 ) 12 = 384 in
2
Find the perimeter of the base
P = 48 + 20 + 16 + 20 = 104 in
Find the surface area
S = Ph + 2B
S = 104 ( 24 ) + 2 ( 384 )
= 2496 + 768
= 3264 in 2
The surface area of the ramp is 3264 in 2
10 Find the area of the base of the larger prism
B = l times w
= 7 times l
= 7 ft 2
Find the perimeter of the base
P = 2 ( 7 ) + 2 ( 1 )
= 14 + 2
= 16 ft
Find the surface area of the larger prism
S = Ph + 2B
S = 16 ( 2 ) + 2 ( 7 )
= 32 + 14
= 46 f t 2
Find the area of the base of the smaller prism
B = l times w
= 1 times 1
= 1 ft 2
Find the perimeter of the base
P = 2 ( 1 ) + 2 ( 1 )
= 2 + 2 = 4 ft
Find the surface area of the smaller prism
S = Ph + 2B
S = 4 ( 3 ) + 2 ( 1 )
= 12 + 2
= 14 ft 2
Add the surface areas of the two prisms and
subtract the parts not on the surface
Surface area = 46 + 14 - 1 - 1 = 58 ft 2
The surface area of the stand is 58 ft 2
11 Find the number of cans of paint needed
58 divide 25 = 232
It takes 2 full cans and 1 partial can so 3 cans are
needed
Find the cost of 3 cans of paint
3 times 679 = 2037
No they need 3 cans which will cost $2037
Copyright copy by Houghton Mifflin Harcourt 64 All rights reserved
12 Find the area of the base of the box
B = l times w
= 27 times 24
= 648 cm 2
Find the perimeter of the base
P = 2 ( 27 ) + 2 ( 24 )
= 54 + 48
= 102 cm
Find the surface area of the box
S = Ph + 2B
S = 102 ( 10 ) + 2 ( 648 )
= 1020 + 1296
= 2316 cm 2
2316 cm 2 will be covered with paper
13 Area of the original base B = l times w
Area of the new base = 2l times 2w = 4lw = 4B
Perimeter of the original = 2l + 2w
Perimeter of the new = 2 ( 2l ) + 2 ( 2w ) =
2 ( 2l + 2w ) = 2P
Original S = Ph + 2B
New S = 2Ph + 2 ( 4B )
No Ph doubles and 2B quadruples S more than
doubles
Focus on Higher Order Thinking
14 Find the area of the base of the prism
B = l times w
= 25 times 25
= 625 ft 2
Find the perimeter of the base
P = 4 ( 25 )
= 10 ft
Find the surface area of the prism
S = Ph + 2B
S = 10 ( 35 ) + 2 ( 625 )
= 35 + 135
= 485 ft 2
Find the surface area less the area of the bottom
surface of the prism
485 - 625 = 4225 ft 2
Find what percent of the surface area less the area
of the bottom is compare to the total surface area
4225 _____ 485
times 100 asymp 87
Sample answer She would be painting about 87
of the total surface area so she will use about 87
of the total amount of paint
15
Circumference ofcircle πd = πtimes4
r = 2 in
9 in
Find the area of the circle base
A = πr 2
asymp 31 4 ( 2 ) 2 = 1256 in 2
Find the circumference of the circle
C = πd
asymp 314 ( 4 ) = 1256 in 2
Find the area of the rectangle
Area asymp 9 times 1256 = 11304 in 2
Find the surface area of the cylinder
S = Ch + 2B
asymp 1256 ( 9 ) + 2 ( 1256 ) = 13816 in 2
Round to the nearest tenth 1382 in 2
The surface area of the oatmeal box is
approximately 1382 in 2
Find the amount of cardboard for 1500 boxes
1500 times 1382 = 207300 in 2
Convert square inches to square feet and round to
the nearest whole number
( 207300 in 2 ) 1 ft 2 _______
144 in 2 asymp 1440 ft 2
It would take about 1440 ft 2 of cardboard
16 Each face has 9 squares 1 cm by 1 cm so S =
54 cm 2 The surface area stays the same when one
or more corner cubes are removed ( Fig 2 3 ) because the number of faces showing is still the
same In Fig 4 S increases because 2 more faces
show
LESSON 95
Your Turn
2 Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 24 ) 7
= 84 m 2
Find the volume of the prism
V = Bh
= ( 84 ) ( 22 )
= 1848 m 3
The volume of the prism is 1848 m 3
5 Find the base area B of the trapezoidal prism
B = 1 __ 2 ( b 1 + b 2 ) h
= 1 __ 2 ( 8 + 12 ) 10
= 1 __ 2 ( 20 ) 10 = 100 cm
2
Find the volume of the prism
V = Bh
= ( 100 ) ( 22 )
= 2200 cm 3
The volume of the prism is 2200 cm 3
7 Find the volume of each prism
Find the base area B of the rectangular prism
B = bh
= ( 13 ) 13
= 169 in 2
Find the volume of the rectangular prism
V = Bh
= ( 169 ) ( 30 )
= 5070 in 3
Copyright copy by Houghton Mifflin Harcourt 65 All rights reserved
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 9 ) 13
= 585 in 2
Find the volume of the triangular prism
V = Bh
= ( 585 ) ( 30 )
= 1755 in 3
Find the sum of the volumes
5070 + 1755 = 6825 in 3
The volume of the composite figure is 6825 in 3
Guided Practice
1 B = 1 __ 2 bh = 1 __
2 ( 8 ) ( 3 ) = 12 ft 2
V = Bh = ( 12 times 7 ) ft 3 = 84 ft 3
2 B = 1 __ 2 ( b 1 + b 2 ) h = 1 __
2 ( 15 + 5 ) 3 = 30 m
2
V = Bh = ( 30 times 11 ) m 3 = 330 m 3
3 Find the base area B of the rectangular prism
B = bh
= ( 4 ) 6 = 24 ft 2
Find the volume of the rectangular prism
V = Bh
= ( 24 ) ( 12 ) = 288 ft 3
The volume of the rectangular prism = 288 ft 3
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 6 ) 4 = 12 ft 2
Find the volume of the triangular prism
V = Bh
= ( 12 ) ( 6 ) = 72 ft 3
The volume of the triangular prism = 72 ft 3
Find the sum of the volumes
288 + 72 = 360 ft 3
The volume of the composite figure = 360 ft 3
4 Find the base area B of the rectangular prism
B = bh
= ( 40 ) ( 50 ) = 2000 ft 2
Find the volume of the rectangular prism
V = Bh
= ( 2000 ) ( 15 ) = 30000 ft 3
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 40 ) ( 10 ) = 200 ft 2
Find the volume of the triangular prism
V = Bh
= ( 200 ) ( 50 ) = 10000 ft 3
Find the sum of the volumes
30000 + 10000 = 40000 ft 3
The volume of the barn is 40000 ft 3
5 Find the base area B of the trapezoidal prism
B = 1 __ 2 ( b 1 + b 2 ) h
= 1 __ 2 ( 10 + 12 ) 5
= 1 __ 2 ( 22 ) 5 = 55 cm
2
Find the volume of the trapezoidal prism
V = Bh
= ( 55 ) ( 7 ) = 385 cm 3
The volume of the container is 385 cm 3
6 Find the volume of each prism using the formula
V = Bh Then add the volumes of all the prisms
Independent Practice
7 The area of the base of the prism is given 35 in 2
Find the volume of the prism
V = Bh
= ( 35 ) ( 5 ) = 175 in 3
The volume of the trap is 175 in 3
8 The shape of the ramp is triangular prism
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 7 ) ( 6 ) = 21 in
2
Find the volume of the triangular prism
V = Bh
= ( 75 ) ( 7 ) = 525 in 3
The volume of the ramp is 525 in 3
9 Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 8 ) ( 4 ) = 16 ft 2
Find the volume of the triangular prism
V = Bh
= ( 16 ) ( 24 ) = 384 ft 3
The space contained within the goal is 384 ft 3
10 Find the base area B of the trapezoidal prism
B = 1 __ 2 ( b 1 + b 2 ) h
= 1 __ 2 ( 7 + 5 ) 4
= 1 __ 2 ( 12 ) 4 = 24 in
2
Find the volume of the trapezoidal prism
V = Bh
= ( 24 ) ( 8 ) = 192 in 3
The volume of the gift box is 192 in 3
11 Find the volume of the triangular prism
V = Bh
= ( 20 ) ( 15 ) = 300 in 3
The units for volume are incorrect the volume is
300 cubic inches
12 The area of the base of the hexagonal prism is
given B = 234 in 3
Find the volume of the hexagonal prism
V = Bh
= ( 234 ) ( 3 ) = 702 in 3
Copyright copy by Houghton Mifflin Harcourt 66 All rights reserved
Find the base area B of the rectangular prism
B = bh
= ( 3 ) ( 3 ) = 9 in 2
Find the volume of the rectangular prism
V = Bh
= ( 9 ) ( 3 ) = 27 in 3
Find the sum of the volumes
702 + 27 = 972 in 3
The volume of the figure is 972 in 3
13 Find the base area B of the larger rectangular prism
B = bh
= ( 75 ) 375 = 28125 m 2
Find the volume of the larger rectangular prism
V = Bh
= ( 28125 ) ( 75 ) asymp 21094 cm 3
Find the base area B of the smaller rectangular
prism
Find the measure of the base
15 - 75 = 75
Find the base area B of the larger rectangular prism
B = bh
= ( 75 ) 375 = 28125 m 2
Find the volume of the smaller rectangular prism
V = Bh
= ( 28125 ) ( 375 ) asymp 10547 cm 3
Find the sum of the volumes of the prisms
21094 + 10547 = 31641 m 3
The volume of the figure rounded to the nearest
hundredth is 31641 m 3
14 Find the volume of the hexagonal candle
V = Bh
= ( 21 ) ( 8 ) = 168 cm 3
Find the amount of wax Josie would have after
making the hexagonal candle
260 - 168 = 92 cm 3
Find the volume of the triangular candle
V = Bh
= ( 7 ) ( 14 ) = 98 cm 3
Find the amount of wax Josie would have after
making the hexagonal candle
260 - 168 = 92 cm 3
Find the area of the base of a triangular candle with
a height of 14 cm
V = Bh
92 = B ( 14 )
92 ___ 14
= B ( 14 ) _____ 14
6 8 ___ 14
= B asymp 657
No the area of the base of the triangular candle
must be less than or equal to about 657 cm 2
15 The base of trapezoidal prism is given 36 in 2 Find
the volume of the trapezoidal prism
V = Bh
= ( 36 ) ( 5 ) = 180 in 3
The base of triangular prism is given 32 in 2
Find the volume of the trapezoidal
prism V = Bh
= ( 32 ) ( 6 ) = 192 in 3
Triangular prism you get 192 in 3 for the same price
you would pay for 180 in 3 with the trapezoidal prism
Focus on Higher Order Thinking
16 Find the area of the base of the trapezoidal prism
V = Bh
286 = B ( 8 )
286 ____ 8 = B ( 8 )
3575 = B
Find the missing dimension of the base of the
trapezoidal prism
1 __ 2 ( 2 + b 2 ) 13 = 3575
1 __ 2 ( 2 + b 2 ) ( 13 ___
13 ) = 3575 _____
13
( 2 ) 1 __ 2 ( 2 + b 2 ) = ( 2 ) 275
2 + b 2 = 55
_ -2 _ -2
b 2 = 35 ft
The missing dimension is 35 ft
17 Find the area of the base of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 10 ) 6 = 30 cm
2
Find the volume of the triangular prism
V = Bh
= ( 30 ) ( 25 ) = 75 cm 3
Find the mass of the doorstop
mass asymp ( V in cm 3 ) ( 86 g
_____ cm
3 )
asymp ( 75 cm 3 ) ( 86 g
_____ cm
3 ) = 645 g
The volume of the doorstop is 75 cm 3 The mass is
about 645 g
18 If both the base and height of the triangular base are
tripled the area of the base is multiplied by 9
Tripling the height of the prism as well means the
volume of the prism is multiplied by 27
19 Use the formula for the volume of a trapezoidal
prism to find a set of dimensions that have a volume
of 120 cm 3
V = Bh
V = [ 1 __ 2 ( b 1 + b 2 ) h 1 ] h 2
120 ≟ [ 1 __ 2 ( 2 + 6 ) 4 ] 75
= [ 1 __ 2 ( 8 ) 4 ] 75
= [ 16 ] ( 75 ) = 120
Try another set of dimensions in the formula
V = Bh
V = [ 1 __ 2 ( b 1 + b 2 ) h 1 ] h 2
120 ≟ [ 1 __ 2 ( 1 + 7 ) 25 ] 12
= [ 1 __ 2 ( 8 ) 25 ] 12
= [ 10 ] 12 = 120
Copyright copy by Houghton Mifflin Harcourt 67 All rights reserved
Sample answers ( 1 ) height of trapezoid = 4 cm
base lengths = 2 cm and 6 cm height of prism
= 75 cm ( 2 ) height of trapezoid = 25 cm base
lengths = 1 cm and 7 cm height of prism = 12 cm
MODULE 9
Ready to Go On
1 r = 7 m A = π r 2 C = 2πr A asymp 314 sdot ( 7 ) 2
C asymp 2 sdot 314 sdot 7 A asymp 314 sdot 49
C asymp 4396 m A asymp 15386 m 2
2 d = 12 cm d = 6 cm so r = 12 ___ 2 = 6 ft
C = πd A = π r 2 C asymp 314 ( 12 ) A asymp 314 sdot ( 6 ) 2
C asymp 3768 cm A asymp 314 sdot 36
A asymp 11304 ft 2
3 The figure is a composite of a semicircle with
diameter = 16 m so radius is 16 ___ 2 = 8m and a
triangle with base = 16 m and height = 10 m
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 8 ) 2
A asymp 1 __ 2 sdot 314 sdot 64
A asymp 10048 m 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 16 sdot 10
A = 1 __ 2 sdot 160
A = 80 m 2
The total area is the sum
80 + 10048 = 18048 m 2
4 The figure is a composite of a parallelogram with
base = 20 cm and height = 45 cm and a rectangle
with length = 20 cm and height = 55 cm
Area of parallelogram A = bh
A = 20 sdot 45
A = 90 c m 2
Area of rectangle
A = ℓw = 20 sdot 55 = 110 c m 2
The total area is the sum
90 + 110 = 200 cm 2
5 Find the area of the triangular base
Area of triangle = 1 __ 2 bh
1 __ 2 ( 4 ) 3 = 6 cm 2
Find the perimeter of the base
P = 3 + 4 + 5 = 12 cm
Find the surface area
S = Ph + 2B
S = 12 ( 10 ) + 2 ( 6 )
thinsp=120 + 12
thinsp= 132 cm 2
Find the volume of the prism
V = Bh
= ( 6 ) 10
= 60 cm 3
6 Find the area of the composite base formed by a
rectangle and a triangle
Area of triangle = 1 __ 2 bh
1 __ 2 ( 4 ) 15 = 3 yd 2
Area of rectangle = bh
( 4 ) 2 = 8 yd 2
Area of the composite base 3 + 8 = 11 yd 2
Find the perimeter of the composite base
P = 4 + 2 + 25 + 25 + 2 = 13 yd
Find the surface area
S = Ph + 2B
S = 13 ( 25 ) + 2 ( 11 )
thinsp= 325 + 22
thinsp= 545 yd 2
The area of the base of the pentagonal prism
is given
B = 234 yd 3
Find the volume of the prism
V = Bh
= ( 11 ) 25
= 275 yd 3
7 Sample answer You can use a composite figure to
model a room then find surface area to decide how
much paint you need to paint the room
Copyright copy by Houghton Mifflin Harcourt 68 All rights reserved
Solutions KeyStatistics
unit
5MODULE 10 Random Samples and Populations
Are You Ready
1 x ___16
=45___40
40x=720
40x ____40
=720____40
x=18
2 x __5=1__
4
4x=5
4x ___4
=5__4
x=5__4=125
3 25___10
=x ___10
125=10x
125____10
=10x ____10
125=x
4 x __6
=2__9
9x= 12
9x ___9
=12___9
x=12___9=4__
3
5 4748495152575960range=60-47=13
6 4566689121213range=13-4=9
7 95979799100106108115range=115-95=20
8 121319273539476671range=71-12=59
9 mean=3+5+7+3+6+4+8+6+9+5_________________________________10
=56
10 mean=81+94+113+67+62+75____________________________6
=82
LESSON 101
Your Turn
4 Yeseveryemployeehadanequalchanceofbeingselected
5 Thequestionisbiasedsincecatsaresuggested
6 ThequestionisnotbiasedItdoesnotleadpeopletopickaparticularseason
Guided Practice
1 Method1ASampleanswer
Random Sample of Seventh Grade Male Students
Student Shoe SizeArturo 75
Jimmy 80
Darnell 90
Ping 75
Zach 85
Jamar 80
BSampleanswer
75+80+90+75+85+80___________________________6
=485____6
asymp81
Meanasymp81
Method2ASampleanswer
Student Shoe Size Student Shoe SizeReggie 85 Ling 85
Stan 80 Marcus 90
Alejandro 90 Tio 85
BSampleanswer
85+80+90+85+90+85____________________________6
=515____6 =86
Mean=size86
2Method1producesresultsthataremorerepresentativeoftheentirestudentpopulationbecauseitisarandomsample
3 Method2producesresultsthatarelessrepresentativeoftheentirestudentpopulationbecauseitisabiasedsample
4 YesSampleanswerWhatisyourfavoritecolor
5 Selectarandomsampleofsufficientsizethatrepresentsthepopulationandaskeachparticipantunbiasedquestions
Independent Practice
6 SampleanswerPaulrsquossamplewasbiasedMaybehisfriendsstudiedmorethanothers
7 SampleanswerNancyrsquossampledidnotincludeasmanystationsThereportcouldincludestationsnationwide
8 ItisabiasedsampleStudentswhoarenrsquotontheteamwonrsquotbeselected
CopyrightcopybyHoughtonMifflinHarcourt 69 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U5M10indd 69 103113 216 AM
9 Itisbiasedbecausestudentswhoarenrsquotinthatclasswonrsquotbeselected
10 Itisarandomsamplebecauseallseventhgradershaveanequalchanceofbeingselected
11 Itisarandomsamplebecausetheorganizationselectsnamesatrandomfromallregisteredvoters
12 Itisbiasedbecausebasketballismentioned
13 Jaersquosquestionisnotbiasedsinceitdoesnotsuggestatypeofarttostudents
Focus on Higher Order Thinking
14 CollinrsquosmethodbetterrepresentstheentirestudentpopulationbecauseheusedarandomsampleKarlrsquosmethodpickedpeoplethatcouldallbefriendsthatgotofootballgamestogetherThesamplemaynotbestrepresenttheentirestudentpopulation
15 a Every10thstudentoutof600meansthatBarbarasurveyed60studentsThiswasarandomsample
b 35___60
= x ____100
xasymp58
Thepercentis58____100
=58
ItappearsreasonablebecauseBarbarausedarandomsampleandsurveyedasignificantpercentofthestudents
16 CarloiscorrectTherearemanyvalidwaystoselectarepresentativesamplefromapopulation
LESSON 102
Your Turn
5 damagedMP3sinsample
______________________sizeofsample
=damagedMP3sinpopulation
________________________sizeofpopulation
6___50
= x_____3500
6sdot70______50sdot70
= x _____3500
420_____3500
= x_____3500
x=420420damagedMP3s
Guided Practice
1
6 7 8 9 10 11 12 13 14 1550 1 2 3 4
2 Orderthedatafindtheleastandgreatestvaluesthemedianandthelowerandupperquartiles
6 7 7 107 114 4 54
Leastvalue
4
Lower quartile
4
Median
65
Upper quartile
7
Greatestvalue11
Drawaboxplot
10 1550
3 Themostcommonagesofchildrenthatusethelibraryare4and7
4 Therangeofagesofchildrenthatusethelibraryisfrom4to11
5 Themedianageofchildrenthatusethelibraryis65
6 defectivephonesinsample
______________________sizeofsample
=defectivephonesinpopulation
_________________________sizeofpopulation
4___60
= x_____4200
4sdot70______60sdot70
= x_____4200
280_____4200
= x_____4200
x=280About280smartphonesintheorderarelikelytobedefective
7 infectedelkinsample
__________________sizeofsample
=infectedelkinpopulation
____________________sizeofpopulation
8___50
= x_____4500
8sdot90______50sdot90
= x_____4500
720_____4500
= x_____4500
x=720About720elkarelikelytobeinfected
8 YoucansetupproportionsusinginformationobtainedinarandomsampleofthepopulationForinstancethenumberofdefectivepartsinabatchcanbeusedtopredicthowmanypartswillbedefectiveinadifferent-sizebatch
divide060
divide060
CopyrightcopybyHoughtonMifflinHarcourt 70 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U5M10indd 70 103113 218 AM
Independent Practice
9 number of people with mispriced item in sample
_______________________________________ size of sample
=
number of people with mispriced item in one day
_______________________________________ size of population
4 ___ 50
= x ____ 600
4 sdot 12 ______ 50 sdot 12
= x ____ 600
48 ____ 600
= x ____ 600
x = 48
About 48 people are likely to have a mispriced item
10 number of boxes with at least one broken crayon in sample
_______________________________________________ size of sample
=
total number of boxes with at least one broken crayon
___________________________________________ size of population
2 ___ 20
= x ____ 130
2 sdot 65 _______ 20 sdot 65
= x ____ 130
13 ____ 130
= x ____ 130
x = 13
About 13 boxes will have at least one broken crayon
11 number of puppies
________________ size of sample
= total number of puppies
___________________ size of population
12 ___ 60
= x _____ 1200
12 sdot 20 ______ 60 sdot 20
= x _____ 1200
240 _____ 1200
= x _____ 1200
x = 240
About 240 puppies are in all of the cityrsquos animal
shelters
12 number of hawks building nests
__________________________ size of sample
= total number of hawks
__________________ size of population
12 ___ 72
= x ______ 10800
12 sdot 150 _______ 72 sdot 150
= x ______ 10800
1800
______ 10800
= x ______ 10800
x = 1800
About 1800 hawks are building nests
13 Yes this seems reasonable because 23 + 27
_______ 2 = 25
is the median of the data
14 Order the data
11 12 12 12 13 13 13 14 14 14 15 17 18 18
19 22
The total number of marathoners is 16 and of those
12 run 13 miles or more
12 ___ 16
= x ____ 100
12 sdot 625 ________ 16 sdot 625
= x ____ 100
75 ____ 100
= x ____ 100
x = 75
No The statement should say that 75 of female
marathoners run 13 or more miles a week
15
6 7 8 9 1050 1 2 3 4
Sample answer Most students at Garland have 2 or
fewer siblings
16 The box plot should show that at least 50 of the
ages are between 20 and 40 years of age
17 Kudrey needs to find the median and the lower and
upper quartiles and plot those points He assumed
all quartiles would be equally long when each
quartile represents an equal number of data values
Focus on Higher Order Thinking
18 Yes the least and greatest data values The median
and quartiles may or may not be actual data values
depending on how many values are in the data
19 A box plot Since every number is different a dot
plot would only have one dot over each value which
doesnrsquot give much information The box plot would
show the median the range and where data values
are concentrated if in fact they are
20 The typical salary at this company is $24000 the
median Yes it is misleading the average is thrown
off by the outlier value of $79000
Copyright copy by Houghton Mifflin Harcourt 71 All rights reserved
9 a 56 + 43 + 62 + 63 + 33 + 34 + 38 + 51 + 59 + 59
___________________________________________ 10
= 498
The average is 498 palms
b 498 sdot 64 = 31872
There are about 3187 palms on the entire farm
Focus on Higher Order Thinking
10 55 + 57 + 57 + 58 + 59 + 59 + 59 + 59 + 59 + 61 + 62 + 62 + 63 + 64 + 66
_________________________________________________________________ 15
= 60
The mean height is 60 inches Yes it is a good sample generated randomly and contains about 20 of the entire
population so it should provide a good estimate of the mean height of all competitors But taking more samples to
gauge the variability among the samples would make for a more valid estimate
11 Sample answer Answers will vary based on each studentrsquos results but should be about 13 or 14
12 Sample answer The larger the size of the random sample the more likely it is to represent the population
accurately
LESSON 103
Guided Practice
1 (1 600) 20
2 50 51 600
3 No In the sample 4 numbers (38 26 31 and 31)
represent defective batteries which is 20 of the
total In the shipment 50 out of 600 or about 8 of
the batteries are defective
4 Sample answer A too-small or non-random sample
is likely to pick unrepresentative data values
Independent Practice
5 Shop A 10 ___ 50
times 500 = 100
Shop B 23 ____ 100
times 500 = 115
Shop C 7 ___ 25
times 500 = 140
Shop A sells 100 whole-wheat bagels
Shop B sells 115 whole-wheat bagels
Shop C sells 140 whole-wheat bagels
6 From most to least likely B A C Shop Brsquos sample
would be the most representative because it
contained the most bagels Shop Crsquos sample would
be the least representative because it contained the
fewest bagels
7 She could use either the Shop A or Shop B sample
Both use a sufficient number of bagels to be
reasonably accurate The sample from Shop C uses
too few bagels to be accurate
8 2 of the 20 T-shirts in the sample are below quality
standards Because 2 ___ 20
times 1000 = 100 the predic-
tion would be that about 100 of the 1000 T-shirts are
below quality standards This is 1 1 __ 3 times the actual
count of 75
Copyright copy by Houghton Mifflin Harcourt 72 All rights reserved
MODULE 10
Ready to Go On
1 The population is the customers in the companyrsquos
computer database The sample is biased because
the customers surveyed are more likely to value their
service
2 number of students who speak 3 or more languages
__________________________________________ size of sample
= total number of students ____________________ size of population
18 ____ 270
= x ______ 30330
18 sdot 337 ____
3 ________
270 sdot 337 ____ 3
= x ______ 30330
2022
______ 30330
= x ______ 30330
x = 2022
About 2022 students speak three or more
languages
3 Two of the random numbers 13 and 167 represent
defective MP3 players
simulated defective players
______________________ size of simulation
= defective players
______________ shipment
2 ___ 10
= x _____ 5000
2 middot 500 _______ 10 middot 500
= x _____ 5000
1000
_____ 5000
= x _____ 5000
x = 1000
Based on the sample about 1000 MP3 players are
defective
4 No the sample is too small compared to the size of
the shipment
5 Sample answer You can make predictions about
populations that are too large to survey
Copyright copy by Houghton Mifflin Harcourt 73 All rights reserved
MODULE 11 Analyzing and Comparing Data
Are You Ready
0875
1 8 ⟌ _
7000
_ -6 400
600
_ -560
40
_ -40
0
0875 875
08
2 5 ⟌ _
40
_ -4 0
0
08 80
025
3 4 ⟌ _
100
_ -80
20
_ -20
0
025 25
03
4 10 ⟌ _
30
_ -3 0
0
03 30
5 4 6 7 7 9 11 15 17
7 + 9
_____ 2 = 8
Median = 8
Mode = 7
6 36 37 40 43 44 49 50 51 56
Median = 44
Mode none
7 9 + 16 + 13 + 14 + 10 + 16 + 17 + 9
________________________________ 8
= 13
Mean = 13
8 108 + 95 + 104 + 96 + 97 + 106 + 94
________________________________ 7 = 100
Mean = 100
LESSON 111
Your Turn
2 Shape dot plots for field hockey players and
softball players have a similar spread
Center center of the field hockey dot plot is less
than the center for softball or basketball players
Spread dot plots for field hockey players and softball
players have a similar spread
3 The median is the middle value Listing the values
in order
1 4 4 4 5 5 5 6 6 6 6 7 7 8 11
In this case median 6 h
range 10 h
The median for internet usage is greater than the
median for exercise and the range is less than the
range for exercise
Guided Practice
1 Class A clustered around two areas
Class B clustered in the middle The dot plots
appear to have about half of the data clustered in
one area
2 Class A two peaks at 4 and 13 mi
Class B looks centered around 7 mi
3 Class A spread from 4 to 14 mi a wide gap with
no data
Class B spread from 3 to 9 mi
4 Class A
4 4 4 4 4 5 5 5 6 6 12 13 13 13 13 14 14
median 6
Class B
3 4 4 4 5 5 5 5 6 6 7 7 7 7 7 8 8 9
median 6
The median for both dot plots is 6 miles
5 Range for class A 14 - 4 = 10 mi
Range for class B 9 - 3 = 6 mi
6 The medians allow you to compare the centers
The ranges allow you to compare the spreads
Independent Practice
7 The dots have a relatively even spread with a peak
at 8 letters
8 The center of the graph is between 6 and 7 letters
9 The dots spread from 3 to 9 letters
10 The mean is the average
3 + 4 + 4 + 5 + 5 + 6 + 7 + 7 + 8 + 8 + 8 + 9
________________________________________ 12
74 ___ 12
asymp 617
Mean asymp 617
3 3 4 5 5 6 7 7 8 8 8 9
Because there are two middle values take their
average
6 + 7
_____ 2 = 13 ___
2 = 65
Median 65
Range 9 - 3 = 6
11 AL clustered in one small interval with an outlier to
the left
VA relatively uniform in height over the same
interval
Copyright copy by Houghton Mifflin Harcourt 74 All rights reserved
12 ALcenteredbetween8and9daysofrainVAcenteredaround10daysofrain
13 ALspreadsfrom1to12daysofrainanoutlierat1VAspreadsfrom8to12daysofrain
14 LynchburgVAhasmoreconsistentlevelsofrainandmorerainpermonthcomparedtoMontgomeryAL
15 GroupAclusteredtotheleftofsize9GroupBclusteredtotherightofsize9
16 OrderedvaluesforgroupA6577757575888888585913Thereare15itemsofdataSince15isoddthereisamiddlenumber8Sothereisnoneedtoaverageanyvalues
MedianforGroupAsize8OrderedvaluesforgroupB859999959595951010105105105115MedianforGroupBsize95
17 GroupArangewithoutlier=13-65=65withoutoutlier=9-65=25GroupBrange=115-85=3
18 SampleanswerGroupAcouldbechildrenandGroupBcouldbeadults
Focus on Higher Order Thinking
19 YesSampleansweronegroupoffivestudentscouldhavethefollowingnumberofpets12345Anothergroupoffivestudentscouldhavethefollowingnumberofpets13335Forbothgroupsofstudentsthemedianwouldbe3andtherangewouldbe4
20RangeanoutliergreatlyincreasestherangewhereasthemedianwillgenerallynotbegreatlyaffectedasitisinthemiddleofallthevaluesAdotplotwillshowboth
LESSON 112
Your Turn
3 SampleanswerTheboxeshavesimilarshapesalthoughGroupBhasashorterboxandshorterwhiskersGroupBrsquosmedianisgreaterthanGroupArsquosGroupBrsquosshorterboxmeansthemiddle50ofitsdataareclosertogetherthanthemiddle50ofGroupArsquos
4 SampleanswerTheshapeissimilartoStoreArsquosThemedianisgreaterthanStoreArsquosandlessthanStoreBrsquosTheinterquartilerangeisaboutthesameasStoreArsquosandlongerthanBrsquos
Guided Practice
1 Minimum72 Maximum88
2 Median79
3 Range88-72=16 IQR85-75=10
4 Themedianheightforhockeyplayersis70inthemedianheightforvolleyballplayersis74Thereforevolleyballplayershavethegreatermedianheight
5 Theminimumheightforhockeyplayersis64intheminimumheightforvolleyballplayersis67inSohockeyplayershavetheshortestplayer
6 IQRforhockeyplayers76-66=10IQRforvolleyballplayers78-68=10BothgroupshaveanIQRof10
7 SampleanswerMinimumandmaximumvaluesmedianrangeandIQRs
Independent Practice
8 CarAhasaminimumof165inandamaximumof210inCarBhasaminimumof160inandamaximumof205inCarAhasamedianof180inCarBhasamedianof185in
9 RangeofCarA210-165=45RangeofCarB205-160=45IQRofCarA195-170=25IQRofCarB200-175=25Bothcarshaverangesof45inandinterquartilerangesof25in
10 CarBhasagreatermediandistancethanCarATheinterquartilerangesarethesamesothemiddle50ofthejumpdistancesforthetwocarshavethesamevariability
11 CarAhaslessvariabilityinthelowestquarterofitsdataandgreatervariabilityinthehighestquarterofitsdataThevariabilityisreversedforCarB
12 CityBhasthelowestpriceof$400andalsohasthehighestpriceof$625
13 MedianforCityA$475MedianforCityB$450Difference475-450=$25CityAhasthehighermedianpriceanditis$25higher
14 SampleanswerCityBabout50ofcarsinCityBleaseforlessthan$450ascomparedtoonly25ofcarsinCityA
15 SampleanswerCityAhasagreatermediancarleasingcostthanCityBCityAhasagreaterIQRofcarleasingcoststhanCityBCityBhasamorepredictablecarleasingcostthanCityAforthemiddle50ofdatavalues
CopyrightcopybyHoughtonMifflinHarcourt 75 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U5M11indd 75 103113 221 AM
Focus on Higher Order Thinking
16 The box plot with the longer box has more variability
in the middle 50 of the values
17 You can identify the minimum and maximum values
and the range of the data You can identify the
quartiles including the lower and upper quartiles
and the median as well as the interquartile range
Together these values help you recognize the
center of the data both the median and the middle
50 It helps you to recognize how spread out the
data are overall and how spread out the middle
50 of the values are around the median A dot
plot contains all the data values which a box plot
does not
18 Sample answer The range tells you very little but
the interquartile range tells you how closely the
middle half of the data cluster around the median
LESSON 113
Your Turn
1 Team 1
Mean
44 + 47 + 67 + 89 + 55 + 76 +85 + 80 + 87 + 69 + 47 + 58 = 804
804 divide 12 = 67
Mean absolute deviation
ǀ 44 - 67 ǀ = 23 ǀ 47 - 67 ǀ = 20
ǀ 67 - 67 ǀ = 0 ǀ 89 - 67 ǀ = 22
ǀ 55 - 67 ǀ = 12 ǀ 76 - 67 ǀ = 9
ǀ 85 - 67 ǀ = 18 ǀ 80 - 67 ǀ = 13
ǀ 87 - 67 ǀ = 20 ǀ 69 - 67 ǀ = 2
ǀ 47 - 67 ǀ = 20 ǀ 58 - 67 ǀ = 11
Mean of absolute values
23 + 20 + 0 + 22 + 12 + 9 +18 + 13 + 20 + 2 + 20 + 11 = 170
170 divide 12 asymp 142
Team 2
Mean
40 + 32 + 52 + 75 + 65 + 70 +72 + 61 + 54 + 43 + 29 + 32 = 625
625 divide 12 asymp 521
Mean absolute deviation
ǀ 40 - 521 ǀ = 121 ǀ 32 - 521 ǀ = 201
ǀ 52 - 521 ǀ = 01 ǀ 75 - 521 ǀ = 229
ǀ 65 - 521 ǀ = 129 ǀ 70 - 521 ǀ = 179
ǀ 72 - 521 ǀ = 199 ǀ 61 - 521 ǀ = 89
ǀ 54 - 521 ǀ = 19 ǀ 43 - 521 ǀ = 91
ǀ 29 - 521 ǀ = 231 ǀ 32 - 521 ǀ = 201
Mean of absolute values
121 + 201 + 01 + 229 +129 + 179 + 199 + 89 +19 + 91 + 231 + 201 = 169
169 divide 12 asymp 141
Difference in means
67 - 521 = 149
149 divide 141 asymp 11
The difference of the means is about 11 times the
MAD
2 There is much more overlap between the two
distributions
Guided Practice
1 Class 1 mean
12 + 1 + 6 + 10 + 1 + 2 + 3 +10 + 3 + 8 + 3 + 9 + 8 + 6 + 8 = 90
90 divide 15 = 6
Class 2 mean
11 + 14 + 11 + 13 + 6 + 7 + 8 + 6 +8 + 13 + 8 + 15 + 13 + 17 + 15 = 165
165 divide 15 = 11
Class 1 mean absolute deviation
ǀ 12 - 6 ǀ = 6 ǀ 1 - 6 ǀ = 5 ǀ 6 - 6 ǀ = 0
ǀ 10 - 6 ǀ = 4 ǀ 1 - 6 ǀ = 5 ǀ 2 minus 6 ǀ = 4
ǀ 3 - 6 ǀ = 3 ǀ 10 - 6 ǀ = 4 ǀ 3 - 6 ǀ = 3
ǀ 8 - 6 ǀ = 2 ǀ 3 - 6 ǀ = 3 ǀ 9 - 6 ǀ = 3
ǀ 8 - 6 ǀ = 2 ǀ 6 - 6 ǀ = 0 ǀ 8 - 6 ǀ = 2
6 + 5 + 0 + 4 + 5 + 4 + 3 + 4 +3 + 2 + 3 + 3 + 2 + 0 + 2 = 46
46 divide 15 asymp 3
Class 2 mean absolute deviation
ǀ 11 - 11 ǀ = 0 ǀ 14 - 11 ǀ = 3 ǀ 11 - 11 ǀ = 0
ǀ 13 - 11 ǀ = 2 ǀ 6 - 11 ǀ = 5 ǀ 7 - 11 ǀ = 4
ǀ 8 - 11 ǀ = 3 ǀ 6 - 11 ǀ = 5 ǀ 8 - 11 ǀ = 3
ǀ 13 - 11 ǀ = 2 ǀ 8 - 11 ǀ = 3 ǀ 15 - 11 ǀ = 4
ǀ 13 - 11 ǀ = 2 ǀ 17 - 11 ǀ = 6 ǀ 15 - 11 ǀ = 2
0 + 3 + 0 + 2 + 5 + 4 + 3 + 5 +3 + 2 + 3 + 4 + 2 + 6 + 2 = 44
44 divide 15 asymp 3
2 Difference in means
11 minus 6 = 5
5 divide 3 asymp 167
3 Sample answer The variation and overlap in the
distributions make it hard to make any convincing
comparison
4 To see how statistical measures vary among the
different samples
Independent Practice
5 23 + 38 + 39 + 48 + 55 + 56 + 71 +86 + 57 + 53 + 43 + 31 = 600
600 divide 12 = 50
ǀ 23 - 50 ǀ = 27 ǀ 38 - 50 ǀ = 12
ǀ 39 - 50 ǀ = 11 ǀ 48 - 50 ǀ = 2
ǀ 55 - 50 ǀ = 5 ǀ 56 - 50 ǀ = 6
ǀ 71 - 50 ǀ = 21 ǀ 86 - 50 ǀ = 36
ǀ 57 - 50 ǀ = 7 ǀ 53 - 50 ǀ = 3
ǀ 43 - 50 ǀ = 7 ǀ 31 - 50 ǀ = 19
27 + 12 + 11 + 2 + 5 + 6 + 21 +36 + 7 + 3 + 7 + 19 = 156
156 divide 12 = 13
The mean is 50degF and the MAD is 13degF
Copyright copy by Houghton Mifflin Harcourt 76 All rights reserved
6 ǀ 23 - 8 ǀ = 15 ǀ 38 - 23 ǀ = 15
ǀ 39 - 24 ǀ = 15 ǀ 48 - 33 ǀ = 15
ǀ 55 - 40 ǀ = 15 ǀ 56 - 41 ǀ = 15
ǀ 71 - 56 ǀ = 15 ǀ 86 - 71 ǀ = 15
ǀ 57 - 42 ǀ = 15 ǀ 53 - 38 ǀ = 15
ǀ 43 - 28 ǀ = 15 ǀ 31 - 16 ǀ = 15
The difference between each average monthly
temperature for City 1 and the corresponding
temperature for City 2 is 15degF
7 50 - 15 = 35
The mean is 35degF and the MAD is 13degF The
mean for City 2 must be 15degF less than the mean
for City 1 and the MAD must be the same
8 50 - 35 = 15
15 divide 13 asymp 12
The difference in the means as a multiple of the
mean absolute deviations is about 12
9
0 4 8 12 16 20 24 28 32 36 40 44
Medians
School B
School A
0 4 8 12 16 20 24 28 32 36 40 44
Means
School B
School A
Both distributions show longer travel times for school
A The distributions of the medians show less
overlap so it is more convincing
10 State A 48 - 38 = 10
10 divide 6 asymp 17
State B 50 - 42 = 8
8 divide 4 = 2
Sample answer The difference in ages is more
significant for State A if you look at the difference in
mean ages but the difference in mean ages is more
significant in State B if you consider variability as
well
11 Smiths Range 70 - 64 = 6
Median 665
Thompsons Range 80 - 74 = 6
Median 77
77 - 665 = 105
105 divide 6 = 175
The difference in the medians is 175 times the
ranges
Focus on Higher Order Thinking
12 Sample answer Jill can reasonably expect the
median of the medians of the samples to be 35
The median of the medians should be close to the
median of the population which should be 35
The outcomes are equally likely
13 Sample answer Ramonrsquos results should produce
more reliable inferences The larger the sample
size the less variability there should be in the
distributions of the medians and means
14 Sample answer Sethrsquos statement is incorrect for any
situation in which the MADs of the population are
not very similar
MODULE 11
Ready to Go On
1 The mean for the start of the school year is given by
5 + 6 + 6 + 7 + 7 + 7 + 7 + 8 + 8 + 8 + 8 + 9 + 9 + 10
________________________________________________ 14
= 105 ____ 14
= 75 mi
The mean for the end of the school year is given by
6 + 6 + 7 + 7 + 8 + 8 + 8 + 8 + 9 + 9 + 9 + 10 + 10 + 10
__________________________________________________ 14
= 115 ___ 14
asymp 82 mi
In summary Start 75 mi End about 82 mi
2 The median is the middle value
List of ordered values for start of school year
5 6 6 7 7 7 7 8 8 8 8 9 9 10
Because there are two middle values take their
average
7 + 8
_____ 2 = 15 ___
2 = 75
Median 75
List of ordered values for end of school year
6 6 7 7 8 8 8 8 9 9 9 10 10 10
Because there are two middle values we would
generally take their average but since they are both
the same and equal to 8
Median 8
Therefore Start 75 mi End 8 mi
3 Range for start of school year 10 - 5 = 5 mi
Range for end of school year 10 - 6 = 4 mi
Therefore Start 5 mi End 4 mi
4 Median for Airplane A 210 in
Median for Airplane B 204 in
Airplane A has a greater median flight length
5 IQR for Airplane A 225 - 208 = 17 in
IQR for Airplane B 230 - 195 = 35 in
Airplane B has a greater interquartile range
Copyright copy by Houghton Mifflin Harcourt 77 All rights reserved
6 The means for the shade plants
7 + 11 + 11 + 12 + 9 + 12 + 8 + 10
______________________________ 8
= 10
The means for the sun plants
21 + 24 + 19 + 19 + 22 + 23 + 24 + 24
__________________________________ 8 = 22
Range of the shade plants 12 - 7 = 5
Range of the sun plants 24 - 19 = 5
Difference in the means 22 - 10 = 12
12 ___ 5
= 24
The difference in the means is 24 times the ranges
7 Sample answer By graphing real-world data you
can identify similarities and differences in related
groups
Copyright copy by Houghton Mifflin Harcourt 78 All rights reserved
MODULE 12 Experimental Probability
Are You Ready
1 6 ___ 10
= 6 divide 2 ______ 10 divide 2
= 3 __ 5
2 9 ___ 15
= 9 divide 3 ______ 15 divide 3
= 3 __ 5
3 16 ___ 24
= 16 divide 8 ______ 24 divide 8
= 2 __ 3
4 9 ___ 36
= 9 divide 9 ______ 36 divide 9
= 1 __ 4
5 45 ___ 54
= 45 divide 9 ______ 54 divide 9
= 5 __ 6
6 30 ___ 42
= 30 divide 6 ______ 42 divide 6
= 5 __ 7
7 36 ___ 60
= 36 divide 12 _______ 60 divide 12
= 3 __ 5
8 14 ___ 42
= 14 divide 14 _______ 42 divide 14
= 1 __ 3
075
9 4 ⟌ _
300
_ -2 80
20
_ -20
0
075
0875
10 8 ⟌ _
7000
_ -6400
600
_ -560
40
_ -40
0
0875
015
11 20 ⟌ _
300
_ -2 00
100
_ -100
0
015
038
12 50 ⟌ _
1900
_ -15 00
4 00
_ -4 00
0
038
13 67 = 67 ____ 100
= 067
14 31 = 31 ____ 100
= 031
15 7 = 7 ____ 100
= 007
16 146 = 100 + 46
= 100 ____ 100
+ 46 ____ 100
= 1 + 046
= 146
17 013 = 13
18 055 = 55
19 008 = 8
20 116 = 116
LESSON 121
Your Turn
3 Because every other number from 1 through 16 is
even choosing an even number is as likely as not
and the probability is 1 __ 2
4 There are 20 possible outcomes when picking a
marble from the jar There are 10 purple marbles
Therefore the probability of picking a purple marble
is 10 ___ 20
or 1 __ 2
5 There are 6 possible outcomes when rolling a cube
There are 2 numbers greater than 4 that can be
rolled 5 and 6 Therefore the probability of rolling a
number greater than 4 is 2 __ 6 or 1 __
3
Solutions KeyProbability
UNIT
6
Copyright copy by Houghton Mifflin Harcourt 79 All rights reserved
7 P(event) + P(complement) = 1
P(5) + P(not 5) = 1
1 __ 8 + P(not 5) = 1
P(not 5) = 7 __ 8
The probability of picking a marble that is not 5 is 7 __ 8
8 P(event) + P(complement) = 1
P(even) + P(odd) = 1
1 __ 2 + P(odd) = 1
P(odd) = 1 __ 2
The probability of rolling an odd number is 1 __ 2
Guided Practice
1 The cards are numbered 1 2 3 4 5 6 7 8 9 10
You pick a number greater than 0 8
You pick an even number 5
You pick a number that is at least 2 7
You pick a number that is at most 0 1
You pick a number divisible by 3 3
You pick a number divisible by 5 2
You pick a prime number 4
You pick a number less than the
greatest prime number 6
2 There are no green playing cards in a standard
deck so randomly picking a green card is
impossible 0
3 There are as many red cards as black cards in a
standard deck so it is as likely as not 1 __ 2
4 All of the numbers are less than 12 so they are also
less than 15 The probability is certain 1
5 There are only two numbers between 1 and 12 that
are divisible by 5 5 and 10 Therefore the probability
is unlikely close to 0
6 There are 5 possible outcomes when spinning the
spinner There are two even numbers 2 and 4
Therefore the probability of the spinner landing on
an even number is 2 __ 5
7 There are 52 possible outcomes when picking a
card from a standard deck There are 13 cards with
diamonds Therefore the probability of picking a
card with a diamond is 13 ___ 52
= 1 __ 4
8 P(event) + P(complement) = 1
P(5) + P(not 5) = 1
1 __ 6 + P(not 5) = 1
P(not 5) = 5 __ 6
The probability of not rolling 5 is 5 __ 6
9 P(event) + P(complement) = 1
P(blue) + P(not blue) = 1
1 __ 3 + P(not blue) = 1
P(not blue) = 2 __ 3
The probability of not landing on blue is 2 __ 3
10 P(event) + P(complement) = 1
P(4) + P(not 4) = 1
1 __ 5 + P(not 4) = 1
P(not 4) = 4 __ 5
The probability of not landing on 4 is 4 __ 5
11 P(event) + P(complement) = 1
P(queen) + P(not queen) = 1
4 ___ 52
+ P(not queen) = 1
P(not blue) = 48 ___ 52
= 12 ___ 13
The probability of not picking a queen is 12 ___ 13
12 Sample answer pulling a red marble out of a bag
that contains only blue marbles pulling a white
marble out of a bag that contains only white marbles
Independent Practice
13 There are 52 possible outcomes when picking from
a standard deck of cards There are 8 cards that
have an ace or a king Therefore the probability of
selecting
an ace or a king is 8 ___ 52
or 2 ___ 13
14 P(event) + P(complement) = 1
P(apple or peach) + P(not apple or peach) = 1
9 ___ 12
+ P(not apple or peach) = 1
P(not apple or peach) = 3 ___ 12
or 1 __ 4
Therefore the probability of picking a piece of fruit
that is not an apple or a peach is 3 ___ 12
or 1 __ 4
15 No it is unlikely that she will have oatmeal for
breakfast Since there are 4 choices the probability
that she will choose oatmeal is 1 __ 4 or 25
16 Purple There are a lot more plants with purple
flowers than with white flowers The probability of
selecting a white-flowered plant is 2 __ 9 while the
probability of selecting a purple-flowered plant is 7 __ 9
17 Because she has more colored T-shirts than white
T-shirts it is likely that she will pick a colored T-shirt
She has 14 total T-shirts and 10 of the shirts are
colored Therefore the probability she will choose a
colored T-shirt is 10 ___ 14
or 5 __ 7
18 1 None of the students in the class have red hair so
it is certain that a randomly chosen student will not
have red hair
Copyright copy by Houghton Mifflin Harcourt 80 All rights reserved
19 a There are 14 total coins and 8 blue coins so the
probability that the coin is blue is 8 ___ 14
or 4 __ 7
b Removing 1 of the 8 blue coins leaves 7 blue
coins Adding 3 more to the 6 red coins makes
9 red coins The total of coins in the bag is now
16 Therefore the probability of choosing a red
coin is 9 ___ 16
c Removing 1 of the 6 red coins leaves 5 red coins
Adding 3 to the 8 blue coins makes 11 blue coins
The total of coins in the bag is now 16 Therefore
the probability of choosing a red coin is 5 ___ 16
Focus on Higher Order Thinking
20 Sample answer If some marbles in a jar are heavier
than others then the heavier marbles would sink
and be less likely to be selected
21 Yes Because there are only two colors selecting
not black is equal to selecting red So
P(not black) + P(black) =P(not black) + P(not red) = 1
22 2 is the number of ways the event can happen 7 is
the number of outcomes in the sample space
landing on blue
LESSON 122
Your Turn
7 The total number of spins is 6 + 14 + 10 = 30
Red 10 ___ 30
= 1 __ 3
Yellow 14 ___ 30
= 7 ___ 15
Blue 6 ___ 30
= 1 __ 5
8 Sample answer Let 1 and 2 represent blue 3 and 4
represent white and 5 and 6 represent blue Toss
the cube 50 times to determine the experimental
probability for each color Predict the next ball will be
the color with the greatest experimental probability
Guided Practice
1 The total number of spins is 14 + 7 + 11 + 8 = 40
A 14 ___ 40
= 7 ___ 20
= 035 = 35
B 7 ___ 40
= 0175 = 175
C 11 ___ 40
= 0275 = 275
D 8 ___ 40
= 1 __ 5 = 020 = 20
2 Sample answer Write ldquoyesrdquo on 6 cards and ldquonordquo on
4 cards Draw a card at random 50 times Use the
number of ldquoyesrdquo cards drawn as the prediction
3 Use an experiment to find the number of times the
event occurs for a certain number of trials
Independent Practice
4 6 ___ 10
or 3 __ 5 It is reasonable to assume that Dreersquos
past performance is an indicator of her future
performance There is no way to accurately
represent 3 __ 5 on a number cube with 6 faces
5 Sample answer Compare the number of wins to the
total number of trials
number of wins _________________ total number of trials
= 8 ___ 48
= 1 __ 6
6 There are 20 possible outcomes when picking a
name Ryan is 1 person Therefore the probability
he is chosen is 1 ___ 20
and the probability he is not
chosen is 19 ___ 20
P(Ryan) + P(not Ryan) = 1
1 ___ 20
+ P(not Ryan) = 1
P(not Ryan) = 19 ___ 20
7 Yes because it is based on actual data of weather
patterns
8 Joan Mica hit the ball 8 ___ 48
times or about 17 of her
times at bat Meanwhile Joan hit the ball 12 ___ 40
times
or 30 of her times at bat Therefore Joan has the
greater experimental probability and is more likely to
get a hit next time
9 Gabbyrsquos experimental probability of hitting an ace
is 4 ___ 10
or 2 __ 5 Gabby could serve 16 aces in her next
40 serves because 2 __ 5 of 40 is 16
10 The experimental probability her dog wonrsquot want to
go outside is 5 ___ 12
or about 417
P(outside) + P(not outside) = 1
7 ___ 12
+ P(not outside) = 1
P(not outside) = 5 ___ 12
or 417
Focus on Higher Order Thinking
11 She did not add 40 and 60 to find the total number
of trials P(heads) = 40 ____ 100
12 Sample answer coin toss Heads represents male
and tails represents female Toss the coin 50 times
and use the results to make a prediction
13 Sample answer Make an index card to represent
each coin then pick one card at random No since
the coins are different sizes they do not each have
the same probability of getting pulled out of my
Copyright copy by Houghton Mifflin Harcourt 81 All rights reserved
LESSON 123
Your Turn
1 P(coffee + small) = number of coffee + small
_____________________ total number of orders
= 60 ____ 400
= 3 ___ 20
= 15
3 P(goId + 20 in) = number of gold + 20 in
_________________________ total number of necklaces sold
= 12 ___ 75
or 4 ___ 25
Guided Practice
1 P(female + age 22ndash39)
= number of female + age 22ndash39
__________________________ total number of patients
= 50 ____ 400
or 1 __ 8
2 Sample answer There are six possible outcomes
standard with vacuum standard with no vacuum
deluxe with vacuum deluxe with no vacuum
superior with vacuum and superior with no vacuum
Students could write the outcomes on six index
cards and put them in a box Then they can draw a
card 50 times record the results and find the
experimental probability that a customer chooses a
deluxe wash with no vacuum by dividing the
frequency of this compound event by 50 the total
number of trials
3 Find the number of occurrences of the compound
event and divide it by the total number of trials
Independent Practice
4 Divide the number of 2 piece + salad orders 33 by
the total number of orders 330
P = number of 2 piece + salad
______________________ total number of orders
= 33 ____ 330
= 1 ___ 10
5 P = number of red notebooks + 150 pages
_______________________________ total number of notebooks sold
= 60 ____ 400
= 3 ___ 20
6 P(red notebook) = number of red notebooks _____________________ total number of notebooks
= 55 + 60 + 23
____________ 400
= 138 ____ 400
= 69 ____ 200
7 12 the total is the product of 3 page-count choices
and 4 color choices
8 She left out the 53 students that read 150 pages
P(7th grade + 100 pages) = 85 ____ 250
= 17 ___ 50
9 Sample answer 8th grade the results table
suggests 8th grade students are the least likely to
have read 150 pages compared to students in 6th or
7th grade
Focus on Higher Order Thinking
10 Greater heads occurs on about half the occasions
that you roll a 6 so the compound event is half as
likely
11 Sample answer For 2 outcomes he could use even
and odd numbers For 3 outcomes he could use
1 or 2 3 or 4 and 5 or 6 For 6 outcomes he could
use each number once
12 P(male + open toe) = 11 ____ 300
P(male has open toe) = 11 ____ 150
No the first scenario
includes females and the second does not
13 No because coins are fair and the probabilities do
not appear to be equally likely
14 Sample answer On a coin heads = male and
tails = female On a number cube (1 or 2) = 6th
grade (3 or 4) = 7th grade and (5 or 6) = 8th
grade Toss the coin and roll the number cube 50
times each Record the number of outcomes that are
heads and 3 or 4
LESSON 124
Your Turn
1 024 times 550 =132 customers
2 No About 371 of the emails out of 12372 will come
back undelivered because 003 times 12372 asymp 371 The
editorrsquos prediction is too high
3 024 times 350 = 84 customers Yes because 107
customers buying two or more pairs would be more
than only 84 customers
Guided Practice
1 030 times 50 = 15 times
2 015 times 365 asymp 55 days
3 No about 1009 of the candles out of 16824 will be
returned because 006 times 16824 asymp 1009
A prediction of 812 is too low
4 No about 746 toys out of 24850 will be defective
because 003 times 24850 asymp 746 A prediction of 872 is
too high
5 98 ____ 100
= x ___ 40
= 39 ___ 40
or 39 times
No if she were late 6 out of 40 times the rate of
being on time would be only 85 in which case the
light-railrsquos claim of 98 is too high
6 18 ____ 100
= x _____ 5000
= 900 _____ 5000
or 900 students Yes the
collegersquos claim is close to the number actually
accepted
times04
times04
times50
times50
Copyright copy by Houghton Mifflin Harcourt 82 All rights reserved
7 Solve a proportion using the experimental probability
to find an expected number of events to happen
Make a prediction based on the expected number of
events
Independent Practice
8 4 ____ 100
= x ____ 200
= 8 ____ 200
or 8 students More students
moved than expected because 12 is more than 8
9 Yes 6th grade 2 ____ 100
= x ____ 250
= 5 ____ 250
or 5 students
7th grade 4 ____ 100
= x ____ 200
= 8 ____ 200
or 8 students
8th grade 8 ____ 100
= x ____ 150
= 12 ____ 150
or 12 students
Since 5 + 8 + 12 = 25 the values in the table
support his claim of 30 students
10 6 ____ 100
= x ____ 300
= 18 ____ 300
or 18 seats If an airplane is
overbooked with 310 passengers only 291 are
expected to show up since 310 times 94 asymp 291
11 006 times 600 = 36 clients If 40 clients did not pay it
would be slightly more than average
12 080 times 20 = 16 team members The coachrsquos claim is
not accurate because the average number of
students at practice is 144 ____ 8 = 8
13 He set up the fraction incorrectly it should be
1 ___ 30
= x ____ 180
Focus on Higher Order Thinking
14 1 __ 2 of 12 = 6 normal rejection rate
500 times 6 = 30 transactions rejected by a
normal gas pump
15 098 times 15000 = 14700 on-time flights Sample
answer No one week of data could be misleading
and not representative of the yearly on-time prob-
ability (because it ignores bad weather etc)
16 Sample answer No They could expect to get 96
responses with the old letter since
4 ____ 100
= x _____ 2400
= 96 _____ 2400
or 96 letters Therefore the
new letter received fewer responses
MODULE 12
Ready to Go On
1 H1 H2 T1 T2
2 6 ___ 10
= 3 __ 5
3 13 ___ 20
4 3 of the 7 total trials resulted in a sum more than 5
Therefore the experimental probability is 3 __ 7
5 I would predict he would reach first base 24 times
because 3 ___ 10
= x ___ 80
= 24 ___ 80
or 24 times
6 You can use the experimental probability based on
observation or simulation to set up a proportion and
use the proportion to predict a value
times15
times15
times24
times24
times2
times2
times3
times3
times2
times2
times25
times25
times8
times8
Copyright copy by Houghton Mifflin Harcourt 83 All rights reserved
MODULE 13 Theoretical Probability and
Simulations
Are You Ready
075
1 4 ⟌ _
300
_ -2 80
20
_ -20
0
075 = 75
04
2 5 ⟌ _
20
_ -2 0
0
04 = 40
09
3 10 ⟌ _
90
_ -9 0
0
09 = 90
035
4 20 ⟌ _
700
_ -6 00
1 00
_ -1 00
0
035 = 35
0875
5 8 ⟌ _
7000
_ thinsp-6 400
600
_ -560
40
_ -40
0
0875 = 875
005
6 20 ⟌ _
100
_ -1 00
0
005 = 5
076
7 25 ⟌ _
1900
_ -17 50
1 50
_ -1 50
0
076 = 76
046
8 50 ⟌ _
2300
_ -20 50
3 00
_ -3 00
0
046 = 46
9 1 - 1 __ 5 = 5 __
5 - 1 __
5
= 4 __ 5
10 1 - 2 __ 9 = 9 __
9 - 2 __
9
= 7 __ 9
11 1 - 8 ___ 13
= 13 ___ 13
- 8 ___ 13
= 5 ___ 13
12 1 - 3 ___ 20
= 20 ___ 20
- 3 ___ 20
= 17 ___ 20
13 8 ___ 15
times 5 __ 8 =
18 ___ 315
times 5 1 ___
8 1
= 1 __ 3
14 2 __ 9 times 3 __
4 =
12 __ 39
times 3 1 ___
4 2
= 1 __ 6
15 9 ___ 16
times 12 ___ 13
= 9 ___ 416
times 12 3 _____
13
= 27 ___ 52
16 7 ___ 10
times 5 ___ 28
= 17 ___
210 times 5
1 ____
28 4
= 1 __ 8
LESSON 131
Your Turn
2 The probability of an event is the ratio of the number
of ways the event can occur to the total number of
equally likely outcomes Therefore
P(rolling a 3 or 4) =
number of sides with 3 or 4 ________________________ total number of sides on cube
= 2 __ 6 = 1 __
3
3 The total number of outcomes in the sample space
is the denominator of the formula for theoretical
probability
Copyright copy by Houghton Mifflin Harcourt 84 All rights reserved
Guided Practice
1
Basket A Basket B
Total number of outcomes5 + 3 + 8
= 16
7 + 4 + 9
= 20
Number of red balls 3 4
P(win) =
Number of red balls
_____________________ Total number of outcomes
3 ___
16 4 ___
20 = 1 __
5
2 To compare the two probabilities of 1 __ 5 and 3 ___
16 use
the least common denominator of 80
1 __ 5 = 16 ___
80
3 ___ 16
= 15 ___ 80
Therefore 16 ___ 80
gt 15 ___ 80
so 1 __ 5 gt 3 ___
16
Choosing Basket B gives you a better chance of
winning
3 There are a total of 6 odd sections The total number
of sections (odd and even) is 11
P(odd) = number of odd sections ____________________ total number of sections
= 6 ___ 11
4 There are a total of 5 even sections The total
number of sections (odd and even) is 11
P(even) = number of even sections ____________________ total number of sections
= 5 ___ 11
5 The total number faces on a number cube is 6 and
rolling either a 3 or 4 is equal to 2 possibilities
P(rolling a 3 or 4) = number of sides with 3 or 4 ________________________ total number of sides on cube
= 2 __ 6 = 1 __
3
6 Sample answer No but it might be reasonably
close
7 Divide the number of ways the event can occur
by 20
Independent Practice
8 P(yellow) = number of yellow sections
_____________________ total number of sections
= 2 __ 6
= 1 __ 3 033 or 33
9 P(blue or green) = number of blue or green sections
___________________________ total number of sections
= 8 ___ 12
= 2 __ 3 067 or 67
10 P(cherry) = number of cherry cough drops
_________________________ total number of cough drops
= 4 ___ 14
= 2 __ 7 029 or 29
11 P(black card) = number of black cards __________________ total number of cards
= 26 ___ 52
= 1 __ 2 050 or 50
12 P(lime) = number of limes ________________________ total number of pieces of fruit
= 12 - 5 ______ 12
= 7 ___ 12
058 or 58
13 There are a total of 20 DVDs There are 12 DVDs
that are not comedies (5 science fiction plus
7 adventure)
P(not a comedy)
= number of DVDs which are not comedies _________________________________ total number of DVDs
= 5 + 7 _________
5 + 7 + 8 = 12 ___
20
= 3 __ 5 060 or 60
14 There are a total of 6 faces on a number cube There
are 2 faces (3 and 4) that are greater than 2 and
less than 5 which means 2 possibilities
P(greater than 2 and less than 5)
= number of sides with 3 and 4 ________________________ total number of sides on cube
= 2 __ 6
= 1 __ 3 033 or 33
15 9 represents the ways the event can occur
13 represents the number of equally likely outcomes
16 There are a total 16 coins and there are 6 coins that
are greater than 5 cents Therefore
P(coin worth more than 5 cents)
= number of coins worth more than 5 cents _________________________________ total number of coins
= 6 ___ 16
or 3 __ 8
The event is choosing a dime or a quarter and 6 of
the 16 coins are dimes or quarters
Focus on Higher Order Thinking
17 Sample answer Riley divided the number of petunia
seeds by the number of begonia seeds rather than
the total number of seeds The correct probability is
5 ______ 5 + 15
= 5 ___ 20
= 1 __ 4
times16
times16
times5
times5
Copyright copy by Houghton Mifflin Harcourt 85 All rights reserved
18 a The total number of students in the club is 35
There are 20 seventh graders Therefore
P(seventh grader) =
number of seventh graders
______________________ total number of students
= 20 ___ 35
= 4 __ 7
There are 15 eighth graders in the club Therefore
P(eighth grader) =
number of eighth graders
_____________________ total number of students
= 15 ___ 35
= 3 __ 7
Because 4 __ 7 gt 3 __
7 choosing a seventh grader is
more likely
b No each student has the same probability of
being selected 1 ___ 35
19 Sample answer The number of trials is twice the
number of marbles in the jar If the probabilities for
each color were the same the number of times that
color was drawn would be twice the number of
marbles with that color in the jar
20 Red The theoretical probability of choosing red is
P(red) = number of red marbles ___________________ total number of marbles
= 8 ___ 20
The experimental probability of choosing red is
14 ___ 40
or 7 ___ 20
Therefore the difference in the theoretical probability
and experimental probability of choosing a red
marble is 8 ___ 20
- 7 ___ 20
= 1 ___ 20
For blue the theoretical probability is
P(blue) = number of blue marbles ____________________ total number of marbles
= 10 ___ 20
The experimental probability is 16 ___ 40
= 8 ___ 20
Therefore the difference in the theoretical probability
and experimental probability of choosing a blue
marble is 10 ___ 20
- 8 ___ 20
= 2 ___ 20
= 1 ___ 10
For yellow the theoretical probability is
P(yellow) = number of yellow marbles
_____________________ total number of marbles
= 2 ___ 20
The experimental probability is 10 ___ 40
= 5 ___ 20
Therefore the difference in the theoretical probability
and experimental probability of choosing a yellow
marble is 5 ___ 20
- 2 ___ 20
= 3 ___ 20
Choosing a red marble has the smallest difference
between theoretical and experimental probability
LESSON 132
Your Turn
3 P(ham sandwich) =
number of combinations containing ham
_________________________________ total number of sandwich combinations
= 4 ___ 12
= 1 __ 3
4 P(sandwich containing Swiss cheese) =
number of combinations containing Swiss
__________________________________ total number of sandwich combinations
= 6 ___ 12
= 1 __ 2
5 To find the sample space make lists of possible
codes First make a list of codes that start with 0
and have 0 as the second digit
0 0 0 0
0 0 0 1
0 0 1 0
0 0 1 1
List of codes that start with 0 and have 1 as the
second digit
0 1 0 0
0 1 0 1
0 1 1 0
0 1 1 1
List of codes that start with 1 and have 0 as the
second digit
1 0 0 0
1 0 0 1
1 0 1 0
1 0 1 1
List of codes that start with 1 and have 1 as the
second digit
1 1 0 0
1 1 0 1
1 1 1 0
1 1 1 1
In total the number of possible outcomes is 16
There are six codes with exactly two 0s
0 0 1 1
0 1 0 1
0 1 1 0
1 0 0 1
1 0 1 0
1 1 0 0
This means the number of outcomes for a code with
exactly two 0s is 6 Therefore
P(Code exactly two 0s)
= number of favorable outcomes ____________________________ total number of possible outcomes
= 6 ___ 16
= 3 __ 8
Copyright copy by Houghton Mifflin Harcourt 86 All rights reserved
Guided Practice
1
1 2 3 4 5 6
11 sdot 1
= 1
1 sdot 2
= 2
1 sdot 3
= 3
1 sdot 4
= 4
1 sdot 5
= 5
1 sdot 6
= 6
22 sdot 1
= 2
2 sdot 2
= 4
2 sdot 3
= 6
2 sdot 4
= 8
2 sdot 5
= 10
2 sdot 6
= 12
33 sdot 1
= 3
3 sdot 2
= 6
3 sdot 3
= 9
3 sdot 4
= 12
3 sdot 5
= 15
3 sdot 6
= 18
44 sdot 1
= 4
4 sdot 2
= 8
4 sdot 3
= 12
4 sdot 4
= 16
4 sdot 5
= 20
4 sdot 6
= 24
55 sdot 1
= 5
5 sdot 2
= 10
5 sdot 3
= 15
5 sdot 4
= 20
5 sdot 5
= 25
5 sdot 6
= 30
66 sdot 1
= 6
6 sdot 2
= 12
6 sdot 3
= 18
6 sdot 4
= 24
6 sdot 5
= 30
6 sdot 6
= 36
2 There are 15 entries in the table that are multiples
of 4 The total number of entries in the table is 36
P(multiple of 4) = number of multiples of 4
_________________________ total number of entries in table
= 15 ___ 36
3 There are 23 entries in the table that are less than
13 The total number of entries is 36
P(less than 13) = number of entries less than 13 _________________________ total number of entries in table
= 23 ___ 36
4 H
HHH HHT
H
H
Coin 1
List
Coin 2
Coin 3 T
T
HTH HTT
H T
T
H
H T
THH THT
T
H T
TTH TTT
Coin 1
List
Coin 2
Coin 3
5 Count the total number of outcomes in the list 8
6 The only way to get three tails is TTT
7 P = number of outcomes with 3 tails __________________________ total number of outcomes
= 1 __ 8
8 There are 3 way(s) to obtain exactly two heads
HHT HTH THH
P = number of outcomes with exactly 2 heads
__________________________________ total number of possible outcomes
= 3 __ 8
9 You need to know the number of equally likely
outcomes in the sample space
Independent Practice
10
Checkered
Red
Checkered
Red
Blue
Black
Checkered
Red
Checkered
Red
Blue
Black
Checkered
Red
Checkered
Red
Blue
Black
Shirt Pants Shoes
Yellow
Red
Green
11 There are 6 combinations that include red shoes
The total number of combinations is 12 Therefore
P(red shoes) = number of combinations with red shoes ________________________________ total number of combinations
= 6 ___ 12
= 1 __ 2
12 There are four combinations that do not include red
Shirt Pants Shoes
Green Blue Checkered
Green Black Checkered
Yellow Blue Checkered
Yellow Black Checkered
P(no red) = number of outfits with no red _______________________ total number of outfits
= 4 ___ 12
= 1 __ 3
13 Let the other three band members be A B and C
The list of possible combinations is
Rhee Pamela
Rhee A
Rhee B
Rhee C
Pamela A
Pamela B
Pamela C
A B
A C
B C
There is a total of 10 combinations Of these only 1
has Rhee and Pamela so
P(Rhee and Pamela)
= Rhee and Pamela ________________________ total number of combinations
= 1 ___ 10
Copyright copy by Houghton Mifflin Harcourt 87 All rights reserved
14 The sample space can be found from adding all
possible combinations of the two numbers
1 2 3 4 5 6
11 + 1
= 2
1 + 2
= 3
1 + 3
= 4
1 + 4
= 5
1 + 5
= 6
1 + 6
= 7
22 + 1
= 3
2 + 2
= 4
2 + 3
= 5
2 + 4
= 6
2 + 5
= 7
2 + 6
= 8
33 + 1
= 4
3 + 2
= 5
3 + 3
= 6
3 + 4
= 7
3 + 5
= 8
3 + 6
= 9
44 + 1
= 5
4 + 2
= 6
4 + 3
= 7
4 + 4
= 8
4 + 5
= 9
4 + 6
= 10
55 + 1
= 6
5 + 2
= 7
5 + 3
= 8
5 + 4
= 9
5 + 5
= 10
5 + 6
= 11
66 + 1
= 7
6 + 2
= 8
6 + 3
= 9
6 + 4
= 10
6 + 5
= 11
6 + 6
= 12
There is a total of 36 possible sums Of these there
are 10 less than 6
P(sum is less than 6)
= number of sums less than 6 ____________________________ total number of possible outcomes
= 10 ___ 36
= 5 ___ 18
15 The sample space can be found from a tree
diagram
Khakis
Shorts
Shirt Pants Shoes
Collared Jeans
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Khakis
Shorts
T-shirt Jeans
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Total number of possible outcomes is 18 the
number of combinations which include jeans but
not sneakers is 4 Therefore
P(jeans but not sneakers)
= number of outfits with jeans no sneakers
_________________________________ total number of possible outcomes
= 4 ___ 18
= 2 __ 9
16 For each chair lift there are 6 possible trails So you
can multiply the number of choices of chair lifts (3)
by the number of trails (6)
17 Because there are 3 choices for the first item and
2 for the second there are 3 middot 2 = 6 possible
outcomes
18 There is a total of 30 possible shoe sizes Of these
the number of red shoes size 9 or larger is 7
Therefore
P(red and size 9 or larger) =
number of red shoes size 9 or larger
______________________________ total number of possible outcomes
= 7 ___ 30
Focus on Higher Order Thinking
19 Sondra orders one item from each column There
are 4 main dishes 4 vegetables and two sides so
the sample space is 4 sdot 4 sdot 2 = 32 The possible
outcomes of Sondrarsquos order are shown in the tree
diagram
Carrots
Sweet potato
Pasta
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Carrots
Sweet potato
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Carrots
Sweet potato
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Carrots
Sweet potato
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Salmon
Beef
Pork
Copyright copy by Houghton Mifflin Harcourt 88 All rights reserved
There are 8 total number of outcomes that include
salmon Therefore
Sondra P(salmon) = 8 ___ 32
= 1 __ 4
Gretchen orders a main dish and a vegetable There
are 4 main dishes and 4 vegetables so the sample
space is 4 sdot 4 = 16 The possible outcomes of
Gretchenrsquos order are shown in the tree diagram
Carrots
Sweet potato
PastaPeas
Asparagus
Carrots
Sweet potato
Peas
Asparagus
Carrots
Sweet potato
Peas
Asparagus
Carrots
Sweet potato
Peas
Asparagus
Salmon
Beef
Pork
There are 4 total number of outcomes that include
salmon Therefore
Gretchen (salmon) = 4 ___ 16
= 1 __ 4
Because the probabilities for Sondra and Gretchen
are equal neither has a greater probability of getting
a meal that includes salmon
20 a For possible two-digit codes consider first codes
that begin with 1 12 13 14 15 There are a total
of 4 possible codes This pattern continues for
each of the 5 digits and therefore we have a total
of 4 + 4 + 4 + 4 + 4 = 20 possible two-digit
codes (four codes each that begin with each of
the numbers 1ndash5)
For possible three-digit codes there are 12
possible codes that begin with 1 and so there are
12 possible codes for each of the numbers 1ndash5
making a total of 5 sdot 12 = 60 possible three-digit
codes
We can predict the number of possible five-digit
codes because we know there are 60 possible
three-digit codes and for each of these there are
only two digits that can be added to the end of
each code to make them five-digit codes These
are the digits that were not used in the three-digit
code and they have two possible orders for a
total of 60 sdot 2 = 120 possible five-digit codes
As a concrete example again consider the three-
digit codes that begin with 1 Tacking on the digits
which are not included in these three-digit codes
in both orders we have 12345 12354 12435
12453 12534 12543 13245 13254 13425
13452 13524 13542 14235 14253 14325
14352 14523 14532 15234 15243 15324
15342 15423 15432 If we do the same for the
three-digit codes beginning with 2ndash5 we will find
the 120 possible five-digit codes
b Now that the numbers can repeat for two-digit
codes take the 20 codes from before and add five
more codes (11 22 33 44 55) which makes a
total of 25 two-digit codes
For three-digit codes take the 60 codes from
before and add the 5 codes that have all digits
the same plus codes which have two digits
which are repeats To find these consider first the
codes with the first two digits the same 112 113
114 115 221 223 224 225 331 332 334 335
441 442 443 445 551 552 553 554 There
are 20 possible codes There are also 20 possible
codes with the last two digits the same Finally
consider the codes where the first and last digits
are the same For the repeated digit 1 we have
121 131 141 151 or 4 possible codes For each
of the digits 1ndash5 we have 4 possible codes for a
total of 4 sdot 5 = 20 Therefore the overall total
60 + 5 + 20 + 20 + 2 = 125 three-digit codes
To solve for how many possible 5 digit codes
there are notice a pattern in the codes For
two-digit codes the total possible codes is the
number of possible digits raised to the power
equal to the number of digits in the code or
52 = 25 For three-digit codes the number of
possible digits is the same and the number
of digits in the code is 3 so we have 53 = 125
Following this pattern there are 55 = 3125
possible five-digit codes
c Sample answer The better choice is to have the
digits repeat there are more unique codes with
repeated digits than without so it would be more
difficult for someone to guess a code for a locker
LESSON 133
Your Turn
1 There are 4 numbers less than 5 on a standard
number cube There are 6 possible outcomes so
P(number less than 5) = 4 __ 6 = 2 __
3
The number of events is 250 Therefore
P(number less than 5) times Number of events =
2 __ 3 times 250 = 16666 or about 167 times
Copyright copy by Houghton Mifflin Harcourt 89 All rights reserved
2 Set up a proportion The probability of getting
heads is 1 __ 2
1 __ 2 = x ___
18
1 __ 2 = x ___
18
x = 9
about 9 times
3 There are 17 total marbles and 8 are red Therefore
P(red) = 8 ___ 17
P(not red) = 1 - 8 ___ 17
= 9 ___ 17
It is more likely that he picks a marble that is not red
4 No Sample answer There is a total of 71 bills in the
bag and there are 11 bills worth $6 or more
Therefore
P(bill worth $6 or more) = 11 ___ 71
This is about a 15 probability so it is not likely you
will win enough to pay for your ticket
Guided Practice
1 An equally likely chance means that the probabilities
of being assigned to each crew are the same and
since there are three possibilities each has a
probability of 1 __ 3
Apartment 1 __ 3 Condo 1 __
3 House 1 __
3
The probability of being assigned to house crew is 1 __ 3
Set up and solve a proportion
1 __ 3 = x ___
18
1 __ 3 = x ___
18
x = 6
This means that Bob can expect to be assigned to
the house crew about 6 times out of 18
2 Since half of the ticket holders will receive a prize
this means that 300 divide 2 = 150 people will receive a
prize Because they are equally likely to receive one
of three prizes the probability of winning each of the
prizes is 1 __ 3 so the probability of winning a movie
ticket is 1 __ 3 The number of events is 150 Therefore
P(movie ticket) times Number of events = 1 __ 3 times 150 =
50 or 50 people are predicted to win a movie ticket
3 The total number of students in Mr Jawaranirsquos class
is 28 The probabilities of picking a student at
random with a certain eye color are
P(hazel) = 9 ___ 28
P(brown) = 10 ___ 28
P(blue) = 7 ___ 28
P(green) = 2 ___ 28
The event with the greatest probability is choosing a
person with brown eyes
4 You can find and compare probabilities Or you can
use probability to set up and solve a proportion or
an equation that relates the probability to the
unknown quantity
Independent Practice
5 The total number of marbles in the bag is 9 The
number of white or gray marbles is 3 Therefore
P(white or gray) = 3 __ 9 = 1 __
3
The number of events is 45 The equation to make a
prediction is then
P(white or gray) times Number of events = 1 __ 3 times 45 = 15
You can expect to get 15 white or gray marbles
6 A spinner which has an equal likelihood to land on
green or yellow means that the number of green and
yellow sections must be equal More likely to land on
red means that there must be more red sections
than yellow or green A Sample answer is
Y GRR
R R
RR
7 Because half the deck is red the probability of
drawing a red card is 1 __ 2 Because there are three
face cards for each of four suits there are 3 sdot 4 = 12
face cards and the probability of drawing a face
card is 12 ___ 52
To compare 1 __ 2 and 12 ___
52 use the least
common denominator of 52 so that 1 __ 2 = 26 ___
52 Given
that 12 ___ 52
lt 26 ___ 52
the probability of drawing a red card
is higher than of drawing a face card and it is more
likely that Dawn draws 2 red cards
8 The total number of aces in a deck is 4 Therefore
P(ace) = 4 ___ 52
= 1 ___ 13
The number of events is 39 The equation to make a
prediction is then
P(ace) middot Number of events = 1 ___ 13
times 39 = 3
He is predicted to draw an ace 3 times
9 The total number of red cards is 26 Therefore
P(red card) = 26 ___ 52
= 1 __ 2
The number of events is 1000 The equation to
make a prediction is then
P(red card) sdot Number of events = 1 __ 2 sdot 1000 = 500
The player is predicted to turn over a red card as the
first card 500 times
10 The sample space can be found from adding all
possible combinations of the two numbers
times6
times6
times9
times9
Copyright copy by Houghton Mifflin Harcourt 90 All rights reserved
1 2 3 4 5 6
1 2 3 4 5 6 7
2 3 4 5 6 7 8
3 4 5 6 7 8 9
4 5 6 7 8 9 10
5 6 7 8 9 10 11
6 7 8 9 10 11 12
There is a total of 36 possible sums Of these there
are 5 ways to roll a sum of 8 and 2 ways to roll a
sum of 11 The probabilities are
P(sum of 8) = 5 ___ 36
P(sum of 11) = 2 ___ 36
Because the probability of rolling a sum of 8 is
greater than that of rolling a sum of 11 ( 5 ___ 36
gt 2 ___ 36
) John is more likely to win
11 There are 5 possible numbers greater than 15 so
P(greater than 15) = 5 ___ 20
= 1 __ 4
The number of events is 180 The equation to make
a prediction is then
P(greater than 15) times Number of events =
1 __ 4 times 180 = 45
The chosen number will be greater than 15 for 45
days in the school year
12 The sample space for a standard cube is 36 and
there are 3 combinations that will have a sum of 4
so P(sum of 3) = 3 ___ 36
= 1 ___ 12
The number of events is 36 The equation to make a
prediction is then
P(sum of 3) times Number of events = 1 ___ 12
middot 36 = 3
Eben is predicted to roll a sum of 4 a total of 3 times
13 Sample answer No Every time you flip a coin the
probability of heads is 1 __ 2 but in reality you could flip
a coin many times and have it land heads up every
time
14 Sample answer A bag of marbles contains red and
blue marbles that are different sizes Since it is easy
to feel the difference between the two colors all of
the outcomes are not equally likely You cannot make
a prediction using theoretical probability
Focus on Higher Order Thinking
15 Sample answer What is the theoretical probability
that the coin lands on heads and you pick a marble
that is not green
The probability that the coin lands on heads is 1 __ 2
and the probability that the picked marble is not
green is 3 + 9 _________
3 + 8 + 9 = 12 ___
20 The product of these two
probabilities is 1 __ 2 times 12 ___
20 = 12 ___
40
16 Sample answer It is much more likely that he rolls a
5 or the coin lands on heads
The probability that Horace rolls a 5 and the coin
lands on heads is given by
P(5 and heads) = 1 __ 2 times 1 __
6 = 1 ___
12
In the case where Horace rolls a 5 or the coin lands
on heads the probability is given by
P(5 or heads) = 1 __ 6 + 1 __
2 - 1 __
6 times 1 __
2 = 7 ___
12
17 Yes but only theoretically because in reality nothing
can occur 05 times Sample answer The probability
that a flipped coin lands heads up is 1 __ 2 so in 75 flips
you can expect heads about 75 ___ 2 or 375 times
LESSON 134
Your Turn
1 Sample answer (data and percent will vary)
Trial Numbers generated 3 Males first
1 0 0 1 No
2 0 1 No
3 1 No
4 0 1 No
5 1 No
6 0 0 0 1 Yes
7 0 0 1 No
8 0 1 No
9 1 No
10 0 0 0 0 1 Yes
For these data the experimental probability that the
elephant gives birth to 3 male calves before having a
female calf is 2 ___ 10
or 20
2 Sample Answer (data and percent will vary)
Trial Numbers generated Correct answers
1 1 0 1 1 0 3
2 0 1 0 0 1 2
3 0 0 0 0 1 1
4 0 0 1 1 0 2
5 1 1 1 1 1 5
6 1 0 0 0 0 1
7 1 0 1 1 0 3
8 1 0 1 0 0 2
9 0 1 1 1 1 4
10 0 0 0 0 0 0
The experimental probability that he gets at least 2
questions right is 7 ___ 10
= 70
Copyright copy by Houghton Mifflin Harcourt 91 All rights reserved
Guided Practice
1 Since there is a 30 or 3 ___ 10
chance of drought let
the numbers 1 to 3 represent years with a drought
and the numbers 4 to 10 represent years without
a drought Since we are interested in the next 4
years perform multiple trials generating 4 random
numbers each time
2
Trial Numbers generated Drought years
1 10 3 5 1 2
2 10 4 6 5 0
3 3 2 10 3 3
4 2 10 4 4 1
5 7 3 6 3 2
6 8 4 8 5 0
7 6 2 2 8 2
8 6 5 2 4 1
9 2 2 3 2 4
10 6 3 1 5 2
3 In 8 out of the 10 trials there was a drought in at
least one of the years The experimental probability
of a drought in at least 1 of the next 4 years is
8 ___ 10
= 80
4 Sample answer Generate whole numbers from
1 to 4 Let 1 to 3 represent the event occurring
and 4 represent the event not occurring
Independent Practice
5 There is only 1 trial Trial 6 where it took exactly
4 contestants to get a winner
6 Since 1 out of 10 trials resulted in exactly
4 contestants the probability is 1 ___ 10
= 10
7 The trials for which at least 4 hurricanes struck are
Trials 2 and 7 or 2 out of 10 trials Therefore the
probability is 2 ___ 10
= 20
8 It is fewer than expected based on the simulation
9 It is unlikely but it is not impossible Each of the 3
numbers could be any number from 1 to 10
However there are 10 possible first numbers 10
possible second numbers and 10 possible third
numbers or a total of 1000 possible numbers when
generating three numbers from 1 to 10 The
probability of generating three 10s is 1 _____ 1000
10 Sample answer Use the numbers 1ndash5 where 1 2
and 3 represent packs which contain a player from
Erikarsquos favorite team Generate numbers randomly
and stop when you get a 1 2 or 3
Trial Numbers generated Number of Packs
1 3 1
2 4 2 2
3 2 1
4 1 1
5 2 1
6 4 5 3 2
7 4 2 2
8 4 5 2 1
9 4 4 3 3
10 5 1 2
The average number of packs she needs to buy is
1 + 2 + 1 + 1 + 1 + 2 + 2 + 1 + 3 + 2
_________________________________ 10
= 16 ___ 10
= 1 3 __ 5
packs Since she cannot buy a fraction of a pack
she must buy 2 packs
Focus on Higher Order Thinking
11 Sample answer The probability that she makes a
shot is 375 = 3 __ 8 Use the whole numbers from 1 to
8 with 1ndash3 representing shots she makes and 4ndash8
representing shots she misses For each new trial
generate 10 random numbers Count the number
of times 1 2 or 3 appears in each trial Divide the
number of trials in which she made at least 3 shots
by the total number of trials
12 Sample answer Their simulation was not
appropriate perhaps because they chose an
incorrect model You would expect there to have
been exactly 4 heads on more of the trials and
more variation in the number of heads in general
MODULE 13
Ready to Go On
1 P(red) = number of red marbles ___________________ total number of marbles
= 12 ___________________ 12 + 12 + 15 + 9 + 12
= 12 ___ 60
= 1 __ 5 020 or 20
2 P(diamond or spade)
= number of diamonds and spades
___________________________ total number of cards
= 13 + 13
_______ 52
= 26 ___ 52
= 1 __ 2 050 or 50
3 The most likely color of marble chosen is the most
common color in this case green
Copyright copy by Houghton Mifflin Harcourt 92 All rights reserved
4 In order to find the experimental probability count
the number of trials in which 1 occurs at least once
In this case there are 4 trials that generated a 1
Therefore the experimental probability is 4 ___ 10
or
40
5 Sample answer You can find the theoretical
probability of an event and then use it to make a
prediction by setting up a proportion
Copyright copy by Houghton Mifflin Harcourt 93 All rights reserved
Cover Image Credits Baja copyRadius ImagesCorbis
Copyright copy by Houghton Mifflin Harcourt Publishing Company
All rights reserved No part of this work may be reproduced or transmitted in any form or by any means electronic or mechanical including photocopying or recording or by any information storage and retrieval system without the prior written permission of the copyright owner unless such copying is expressly permitted by federal copyright law Requests for permission to make copies of any part of the work should be addressed to Houghton Mifflin Harcourt Publishing Company Attn Contracts Copyrights and Licensing 9400 Southpark Center Loop Orlando Florida 32819-8647
Printed in the USA
ISBN 978-0-544-20723-3
1 2 3 4 5 6 7 8 9 10 XXXX 22 21 20 19 18 17 16 15 14 13
4500000000 B C D E F G
If you have received these materials as examination copies free of charge Houghton Mifflin Harcourt Publishing Company retains title to the materials and they may not be resold Resale of examination copies is strictly prohibited
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DO NOT EDIT--Changes must be made through File info CorrectionKey=B
7_MCABESK207233_FMCPindd 2 11713 600 PM
Table of Contents
UNIT 1 The Number System
Module 1Lesson 11 1
Lesson 12 2
Lesson 13 3
Lesson 14 4
Module 2Lesson 21 6
Lesson 22 7
Lesson 23 8
Module 3Lesson 31 10
Lesson 32 14
Lesson 33 15
Lesson 34 17
Lesson 35 18
Lesson 36 20
UNIT 2 Ratios and Proportional
Relationships
Module 4Lesson 41 23
Lesson 42 25
Lesson 43 25
Module 5Lesson 51 28
Lesson 52 29
Lesson 53 30
UNIT 3 Expressions Equations
and Inequalities
Module 6Lesson 61 32
Lesson 62 34
Lesson 63 35
Lesson 64 37
Module 7Lesson 71 43
Lesson 72 46
Lesson 73 47
UNIT 4 Geometry
Module 8Lesson 81 53
Lesson 82 54
Lesson 83 54
Lesson 84 55
Module 9Lesson 91 57
Lesson 92 59
Lesson 93 60
Lesson 94 63
Lesson 95 65
UNIT 5 Statistics
Module 10Lesson 101 69
Lesson 102 70
Lesson 103 72
Module 11Lesson 111 74
Lesson 112 75
Lesson 113 76
Copyright copy by Houghton Mifflin Harcourt iiiAll rights reserved
Table of Contents
UNIT 6 Probability
Module 12Lesson 121 79
Lesson 122 81
Lesson 123 82
Lesson 124 82
Module 13Lesson 131 84
Lesson 132 86
Lesson 133 89
Lesson 134 91
Copyright copy by Houghton Mifflin Harcourt ivAll rights reserved
MODULE 1 Adding and Subtracting Integers
Are You Ready
1 an elevator ride down 27 stories -27
2 a $700 profit 700
3 46 degrees below zero -46
4 a gain of 12 yards 12
1 1
5 183
_ + 78
261
261
5 16 17
6 677
_ -288
389
389
1 1
7 1188
_ +902
2090
2090
1 15 14
8 2647
_ -1885
762
762
9
-8-10 -4-6 -2 2 4 6 8 100 10
-8-10 -4-6 -2 2 4 6 8 100 11
-8-10 -4-6 -2 2 4 6 8 100 12
-8-10 -4-6 -2 2 4 6 8 100
LESSON 11
Your Turn
7 -8 + ( -1 ) = -9
8 -3 + ( -7 ) = -10
9 -48 + ( -12 ) = -60
10 -32 + ( -38 ) = -70
11 109 + 191 = 300
12 -40 + ( -105 ) = -145
13 -150 + ( -1500 ) = -1650
14 -200 + ( -800 ) = -1000
Guided Practice
1 a There are 6 counters
b The red counters represent negative numbers
c -5 + ( -1 ) = -6
2 a There are 9 counters
b The red counters represent negative numbers
c -2 + ( -7 ) = -9
3 -5 + ( -2 ) = -7
-8-7-6-5 -2-1 0-4-3 4 -1 + ( -3 ) = -4
-5-4-3-2 1 2 3-1 0 5 -3 + ( -7 ) = -10
-10 -9-8-7 -4-3-2-6-5 6 -4 + ( -1 ) = -5
-5-4-3-2 1 2 3-1 0 7 -2 + ( -2 ) = -4
-5-4-3-2 1 2 3-1 0 8 -6 + ( -8 ) = -14
-16 -12 -4 0-8 9 -5 + ( -4 ) = -9
10 -1 + ( -10 ) = -11
11 -9 + ( -1 ) = -10
12 -90 + ( -20 ) = -110
13 -52 + ( -48 ) = -100
14 5 + ( 198 ) = 203
15 -4 + ( -5 ) + ( -6 ) = -15
16 -50 + ( -175 ) + ( -345 ) = -570
17 Add their absolute values Use the sign of the
integers as the sign of the sum
Solutions KeyThe Number System
UNIT
1
Copyright copy by Houghton Mifflin Harcourt 1 All rights reserved
Independent Practice
18 a
-4
-6
-8
-2
0
2
-5 + (-3)-3 + (-5)
b No -5 + ( -3 ) is -8 and -3 + ( -5 ) is also -8
19 -3 + ( -1 ) + ( -5 ) + ( -2 ) = -11 the golferrsquos total
score is -11
20 -3 + ( -6 ) = -9 the team lost a total of 9 yards
21 -14 + ( -5 ) + ( -12 ) + ( -23 ) = -54 The total
sack yardage was -54
22 a -10 + ( -8 ) = -18
b -6 + ( -2 ) = -8
c -18 lt -8 Jonestown
23 -100 + ( -75 ) + ( -85 ) = -260
Focus on Higher Order Thinking
24 a -25 + ( -45 ) + ( -75 ) = -145 Jan withdrew
$145
b -35 + ( -55 ) + ( -65 ) = -155 Julie withdrew
$155
c Sample answer $45 $55 and $65
25 It is easier to add -80 + ( -20 ) fi rst to get -100
and then add -173 to get -273
26 Disagree there are three pairs of positive integers
1 and 7 2 and 6 and 3 and 5 and three pairs of
negative integers -1 and -7 -2 and -6 -3 and
-5 The absolute value of the sum of any of these
six pairs is 8
LESSON 12
Your Turn
7 -51 + 23
ǀ -51 ǀ - ǀ 23 ǀ = 28
-51 + 23 = -28
8 10 + ( -18 )
ǀ -18 ǀ - ǀ 10 ǀ = 8
10 + ( -18 ) = -8
9 13 + ( -13 )
ǀ 13 ǀ - ǀ -13 ǀ = 0
10 25 + ( -26 )
ǀ -26 ǀ - ǀ 25 ǀ = 1
25 + ( -26 ) = -1
Guided Practice
1 9 + ( -3 ) = 6
2 3 4 5 8 9 106 7 2 -2 + 7 = 5
-3-2-1 0 3 4 51 2 3 -15 + 4 = -11
-18 -16 -12 -10-14 4 1 + ( -4 ) = -3
-5-4-3-2 1 2 3-1 0 5 -4 + 5 = 1
6 -6 + 6 = 0
7 2 + ( -5 ) = -3
8 -3 + 7 = 4
9 -8 + 14 = 6
10 7 + ( -5 ) = 2
11 5 + ( -21 ) = -16
12 14 + ( -14 ) = 0
13 0 + ( -5 ) = -5
14 32 + ( -8 ) = 24
15 To fi nd -4 + 2 start at -4 and move 2 units to the
right to -2 To fi nd the sum -4 + ( -2 ) start at -4
and move 2 units to the left to -6
Independent Practice
16 -15 + 71 = 56
17 -53 + 45 = -8
18 -79 + 79 = 0
19 -25 + 50 = 25
20 18 + ( -32 ) = -14
21 5 + ( -100 ) = -95
22 -12 + 8 + 7 = 3
23 -8 + ( -2 ) + 3 = -7
Copyright copy by Houghton Mifflin Harcourt 2 All rights reserved
24 15 + ( -15 ) + 200 = 200
25 -500 + ( -600 ) + 1200 = 100
26 9 + ( -22 ) = -13 the team lost 13 yards
27 -55 + 275 = 220 the teamrsquos profi t was $220
28 -47 + 47 = 0 Alexrsquos new balance is $0
29 Sample answer 10 and -2 and 12 and -4
30 Bart won Bartrsquos score = 123 + ( -180 ) = -57
points Samrsquos score = 185 + ( -255 ) = -70 points
-57 gt -70 so Bart has the greater score
Focus on Higher Order Thinking
31 Start at -4 and move 3 to the right to reach -1
Start at 3 and move 4 to the left to reach -1
The sums are equivalent by the Commutative
Property of Addition
32 The weight is dropped from 4 feet above the surface
Add -12 to represent the distance the weight falls
before it hits the bottom 4 + ( -12 ) = -8 The water
is 8 feet deep
33 Sample answer A model with more positive
counters than negative counters represents a sum of
two integers whose sum is positive
34 The sign of the other integer is positive and its value
is 6 or greater Sample explanation If you start at
-5 on a number line you have to move to the right 6
or more units to get a sum that is positive
LESSON 13
Your Turn
4 -7 - 2 = -7 + ( -2 )
-7 + ( -2 ) = -9
5 -1 - ( -3 ) = -1 + 3
-1 + 3 = 2
6 3 - 5 = 3 + ( -5 )
3 + ( -5 ) = -2
7 -8 - ( -4 ) = -8 + 4
-8 + 4 = -4
Guided Practice
1 5 - 8 = -3 Start with 5 positive counters
Add 3 zero pairs and remove 8 positive counters
3 negative counters are left so the difference is -3
2 -5 - ( -3 ) = -2 Start with 5 negative counters
and remove 3 negative counters 2 negative
counters are left so the difference is -2
3 -4 - 5 = -4 + ( -5 ) = -9
0-1-2-3-4-5-6-7-8-9 4 1 - 4 = 1 + -4 = -3
0 1 2 3 4-1-2-3-4 5 8 - 11 = 8 + ( -11 ) = -3
6 -3 - ( -5 ) = -3 + 5 = 2
7 15 - 21 = 15 + ( -21 ) = -6
8 -17 - 1 = -17 + ( -1 ) = -18
9 0 - ( -5 ) = 0 + 5 = 5
10 1 - ( -18 ) = 1 + 18 = 19
11 15 - 1 = 14
12 -3 - ( -45 ) = -3 + 45 = 42
13 19 - ( -19 ) = 19 + 19 = 38
14 -87 - ( -87 ) = -87 + 87 = 0
15 To subtract an integer add its opposite Sample
example 6 - 8 = 6 + ( -8 ) = -2
Independent Practice
16 To fi nd the change to Theorsquos account subtract the
initial balance -$4 from the fi nal balance $25
25 - ( -4 ) = 25 + 4 = 29
The overall change is $29
17 To fi nd the change in elevation subtract the
beginning elevation of -225 feet from the fi nal
elevation of -127 feet
-127 - ( -225 ) = -127 + 225 = 98
The change in elevation was 98 feet
18 Subtract the low temperature -2degF from the high
temperature 90degF
90 - ( -2 ) = 92
The difference between the high and low
temperatures is 92degF
19 Subtract Cheyennersquos score at the end of her turn
from her score at the start of her turn to fi nd the
change in Cheyennersquos score during her turn
-425 - ( -275 ) = -425 + 275 = -150
The change in Cheyennersquos score is -150 points
20 a Final temperature - initial temperature = change
in temperature
Gas A -8 - ( -21 ) = -8 + 21 = 13
13degC increase
Gas B 12 - ( -12 ) = 12 + 12 = 24
24degC increase
Gas C -15 - ( -19 ) = -15 + 19 = 4
4degC increase
b Negative the fi nal temperatures will be less than
the initial temperature because the gas is cooler
So the difference in temperatures will be negative
21 Diet Chow the catrsquos weight changed by
-8 + ( -18 ) = -26 ounces with Diet Chow and
3 + ( -19 ) = -16 ounces with Kitty Diet
Focus on Higher Order Thinking
22 Sample answer Susanne owed her sister $4 Then
she borrowed $10 more How much does Susanne
owe her sister in all
23 Tom found -11 - 4 instead of -11 - ( -4 ) To
subtract -4 he should add the opposite of -4
-11 + 4 = -7
Copyright copy by Houghton Mifflin Harcourt 3 All rights reserved
24 YouranswerwillbegreaterthantheintegeryoustartedwithbecausewhenyousubtractanegativeintegeryouadditsoppositeapositiveintegerForexample-5-( -3)=-5+3=-2-2gt-5
25 -16-21-26subtract5togetthenextterm
LESSON 14
Your Turn
1 Starts-Descends+Ascends-40-13+18=-53+18 =-3535feetbelowthecaveentrance
3 Usenegativeintegersforcheckamountsanduseapositiveintegerforamountdeposited-35+( -45)+180=-80+180 =100$100increase
4 JimJim-10-18+5-12=-10-18-12+5 =-( 10+18+12)+5 =-40+5 =-35Jimrestedat-35feet(35feetbelowthesurface)Carla0-20+5-18=0+5-20-18 =0+5-( 20+18) =5-38 =-33Carlarestedat-33feet(33feetbelowthesurface)
Guided Practice
1 -15+ 9- 12= -6- 12 =-1818feetbelowsealevel
2 -23+5-7=-18-7 =-25-25degF
3 50-40+87-30=10+87-30 =97-30 =6767points
4 -6+15+15=-6+30 =24
5 9- 4- 17= 9- 21 =-12
6 50-42+10=8+10 =18
7 6+13+7-5=19+2 =21
8 65+43-11=108-11 =97
9 -35-14+45+31=-49+76 =27
10 -12+6-4=-6-4 =-10-34-3+39=-37+39 = 2 -10lt2( -12+6-4)lt( -34-3+39)
11 21-3+8=18+8 =26-14+ 31- 6= 17- 6 =11 26gt11( 21-3+8)gt( -14+31-6)
12 SampleanswerAddandsubtractfromlefttoright-5+12+10-7=7+10-7=17-7=10
Independent Practice
13 a 5-1+6-1=9
b 9isapositivescoresoitisoverpar
c 9overparislessthan15overparYesCameronbeathisbestgolfscore
14 -6+14-11=-33feetunderground
15 TheCommutativePropertydoesnotapplytosubtraction3-6+5=2and3-5+6=4
16 a -350+275+70-50=-55Leersquosfinalscoreis-55points
b 45gt-55Barry
17 a 300to400
b 75+30-12+14-8+18-30=75+18+6-12=8787customersmustleavebetween400and500
18 100-18+22-53=51$51
19 45-17-22+18=24$24
20 Carlarsquosaccountdecreased$49-18+22-53=-49andLetarsquosaccountonlydecreased$21-17-22+18=-21Carlarsquosaccounthadthegreatestdecreaseinvalue
Focus on Higher Order Thinking
21 SampleanswerTimoweshisbrother1dollarHeborrows6moredollarsfromhisbrotherHepayshisbrotherback3dollarsHowmuchdoesTimstillowehisbrother-1-6+3=-4$4
22 Nothetotalamountshecouldpayherparentsis10+12+25=47and50-47=3Soshestillneeds$3
23 SampleanswerInthecaseinwhichthefirstnumberispositivethenthesumoftheabsolutevaluesoftheothertwonumbersmustbegreaterthanthevalueofthefirstnumberSampleexample13-5-10=-2ǀ 5ǀ+ǀ 10ǀ=15whichisgreaterthan13
MODULE 1
Ready to Go On
1 -8+( -6)=-14
2 -4+( -7)=-11
3 -9+( -12)=-21
CopyrightcopybyHoughtonMifflinHarcourt 4 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U1M01indd 4 103113 206 AM
4 5 + ( -2 )
ǀ 5 ǀ - ǀ -2 ǀ = 3
5 + ( -2 ) = 3
5 -8 + 4
ǀ -8 ǀ - ǀ 4 ǀ = 4
-8 + 4 = -4
6 15 + ( -8 )
ǀ 15 ǀ - ǀ -8 ǀ = 7
15 + ( -8 ) = 7
7 2 - 9 = 2 + ( -9 )
2 + ( -9 ) = -7
8 -3 - ( -4 ) = -3 + 4-3 + 4 = 1
9 11 - ( -12 ) = 11 + 12
11 + 12 = 23
10 -15 + 9 - 4 = -6 - 4
= -10
There are 10 fewer people on the bus
11 24 + 8 - 12 - 9 = 24 + 8 - ( 12 + 9 ) = 32 - 21
= 11
There are 11 cards left in the stack
12 Sample answer Tonya owes her sister $10 and
her friend $5 By how much will her savings change
after she pays them
-10 + ( -5 ) = -15 $15 decrease
Copyright copy by Houghton Mifflin Harcourt 5 All rights reserved
MODULE 2 Multiplying and Dividing Integers
Are You Ready
1 9 times 3 = 27
2 7 times 10 = 70
3 9 times 8 = 72
4 15 times 10 = 150
5 6 times 9 = 54
6 10 times 23 = 230
7 9 times 9 = 81
8 10 times 20 = 200
9 54 divide 9 = 6
10 42 divide 6 = 7
11 24 divide 3 = 8
12 64 divide 8 = 8
13 90 divide 10 = 9
14 56 divide 7 = 8
15 81 divide 9 = 9
16 110 divide 11 = 10
17 12 + 8 divide 212 + 4
16
18 15 - ( 4 + 3 ) times 2
15 - 7 times 2
15 - 14
1
19 18 - ( 8 - 5 ) 2
18 - ( 3 ) 2
18 - 9
9
20 6 + 7 times 3 - 5
6 + 21 - 5
27 - 5
22
21 9 + ( 2 2 + 3 ) 2 times 2
9 + ( 4 + 3 ) 2 times 2
9 + ( 7 ) 2 times 2
9 + 49 times 2
9 + 98
107
22 6 + 5 - 4 times 3 divide 2
6 + 5 - 12 divide 2
6 + 5 - 6
11 - 6
5
LESSON 21
Your Turn
4 Since the numbers have opposite signs the product
will be negative
ǀ -3 ǀ times ǀ 5 ǀ = 3 times 5 = 15
-3 ( 5 ) = -15
5 Since the numbers have the same sign the product
will be positive
ǀ -10 ǀ times ǀ -2 ǀ = 10 times 2 = 20
( -10 ) ( -2 ) = 20
6 One of the factors is 0 so the product is 0
0 ( -22 ) = 0
7 Since the numbers have the same sign the product
will be positive
8 ( 4 ) = 32
Guided Practice
1 -1 ( 9 ) = -9
2 14 ( -2 ) = -28
3 ( -9 ) ( -6 ) = 54
4 ( -2 ) ( 50 ) = -100
5 ( -4 ) ( 15 ) = -60
6 -18 ( 0 ) = 0
7 ( -7 ) ( -7 ) = 49
8 -15 ( 9 ) = -135
9 ( 8 ) ( -12 ) = -96
10 -3 ( -100 ) = 300
11 0 ( -153 ) = 0
12 -6 ( 32 ) = -192
13 7 ( -75 ) = -525 -$525
14 Start at zero and move 5 units to the left 3 times
3 ( -5 ) = -15 the team lost 15 yards
15 6 ( -2 ) = -12 -12degF
16 Multiply the absolute values of the integers If both
integers have the same sign the product is positive
If they have different signs the product is negative
Independent Practice
17 No her number line shows the correct result -6
but she modeled 2 ( -3 ) instead of -2 ( 3 )
18 2 ( -3 ) = -6 he went down 6 floors
19 5 ( -4 ) = -20 $20 decrease
20 Adam descended 5 feet a total of 5 times
5 ( -5 ) = -25 Adam is 25 feet below sea level
21 7 ( -6 ) = -42 the cost of the jeans decreased by
$42 over the 7 weeks
22 9 ( -6 ) = -54 -54 ( 2 ) = -108 Casey has $108
less in his savings
23 7 ( -8 ) = -56 7 ( -5 ) = -35
-56 + ( -35 ) = -91 The savings decreased by $91
24 Sample answer Dave plays a video game in which
he loses 20 points every time he misses a goal
He misses 8 goals 8 ( -20 ) = -160 he loses
160 points
Copyright copy by Houghton Mifflin Harcourt 6 All rights reserved
25 a 3 ( 3 ) ( -3 ) = 9 ( -3 ) = -27
b 3 ( -3 ) ( -3 ) = -9 ( -3 ) = 27
c -3 ( -3 ) ( -3 ) = 9 ( -3 ) = -27
d 3 ( 3 ) ( 3 ) ( -3 ) = 9 ( 3 ) ( -3 ) = 27 ( -3 ) = -81
e 3 ( 3 ) ( -3 ) ( -3 ) = 9 ( -3 ) ( -3 ) = -27 ( -3 ) = 81
f 3 ( -3 ) ( -3 ) ( -3 ) = -9 ( -3 ) ( -3 ) = 27 ( -3 ) = -81
g When a product of integers has an odd number of
negative factors like -3 ( -3 ) ( -3 ) = -27 and
3 ( 3 ) ( 3 ) ( -3 ) = -81 the sign of the product is
negative
When a product of integers has an even number
of negative factors like ( 3 ) ( -3 ) ( -3 ) = 27 and
3 ( 3 ) ( -3 ) ( -3 ) = 9 ( -3 ) ( -3 ) = 81 the sign of the
product is positive
Focus on Higher Order Thinking
26 -1 ( 3 ) ( 1 ) 1 ( -3 ) ( 1 ) -1 ( -3 ) ( -1 )
27 Unless one of the factors is 0 whenever the factors
have opposite signs the product will be less than or
equal to both of the two factors
28 The sign of the product is equal to the sign of the
integers The sign of the product of the first two
integers will always be positive Multiplying this
product by the remaining factor will make a positive
product if the factor is positive negative if it is
negative
LESSON 22
Your Turn
2 Since only the dividend is zero the quotient is 0
0 divide ( -6 ) = 0
3 Since the numbers have opposite signs the quotient
will be negative
38 divide ( -19 ) = -2
4 Since the numbers have the same sign the quotient
will be positive
-13 divide ( -1 ) = 13
5 Yolanda received the same number of penalties in
each game -25 divide ( -5 ) = 5 and -35 divide ( -7 ) = 5
Guided Practice
1 -14 ____ 2 = -7
2 21 divide ( -3 ) = -7
3 26 ____ -13
= -2
4 0 divide ( -4 ) = 0
5 -45 ____ -5 = 9
6 -30 divide ( 10 ) = -3
7 -11 ____ -1
= 11
8 -31 divide ( -31 ) = 1
9 0 ___ -7 = 0
10 -121 _____ -11
= 11
11 84 divide ( -7 ) = -12
12 500 ____ -25
= -20
13 -6 divide ( 0 ) = undefined any number divided by 0 is
undefined
14 -63 ____ -21
= 3
15 -40 divide ( 4 ) = -10 $10
16 -22 divide ( 11 ) = -2 2 points
17 -75 divide ( -15 ) = 5 5 targets
18 -99 divide ( -9 ) = 11 11 times
19 In both cases if the signs of the initial numbers are
the same the answer will be positive If the signs are
different the answer will be negative
Independent Practice
20 -24 divide ( 12 ) = -2 $2
21 Elisa made a greater number of withdrawals She
made -140 divide ( -20 ) = 7 withdrawals Francis made
-270 divide ( -45 ) = 6 withdrawals and 7 gt 6
22 a -2 - 10 = -12 the temperature decreased 12degF
b -12 divide ( 12 ) = -1 decreased by 1degF each hour
23 The first part the rate of change for the first part
is -200 ft _______ 10 min
= -20 ftmin and the rate of change for
the second part is -300 ft _______ 20 min
= -15 ftmin
20 ftmin gt 15 ftmin
24 Sample answer A football team lost 50 yards due to
5 penalties If the team lost the same number of
yards for each penalty what was the change in field
position for each penalty
25 Sample answer a = - 20 and b = 5 less than
-20 divide 5 = -4 and -20 times 5 = -100
-100 lt -4
26 True if the integers have the same sign the product
and quotient are positive if they have different signs
negative
27 False division by 0 is undefined for any dividend
Focus on Higher Order Thinking
28 a 100 divide 25 = 4 4 points
b -16 divide ( -4 ) = 4 Fred answered 4 questions
incorrectly
29 a divide ( -3 ) = 8
a = -24
8 divide b = -4
a divide b = -24 divide ( -2 ) = 12
Copyright copy by Houghton Mifflin Harcourt 7 All rights reserved
30 Dividing integers with the same sign results in a
positive number Since the original two integers are
negative the quotient is greater than both of these
integers
LESSON 23
Your Turn
1 Reggie earned 110 points
3 ( -30 ) + 200 = -90 + 200
= 110
2 -6 ( 13 ) - 21 = -78 - 21
= -99
4 ( -12 ) divide 6 + 2 = -2 + 2
= 0
5 -87 divide ( -3 ) -9 = 29 - 9
= 20
6 40 divide ( -5 ) + 30 = -8 + 30
= 22
7 -39 divide 3 -15 = -13 - 15
= -28
8 Amber moved 3 ( -3 ) + 5 = -4 or 4 places back
Will moved 2 ( -4 ) + 3 = -5 or 5 places back Will
moved further back
9 ( -10 ) divide 2 - 2 = -5 - 2 = -7
( -28 ) divide 4 + 1 = -7 + 1 = -6
10 42 divide ( -3 ) + 9 = -14 + 9 = -5
( -36 ) divide 9 - 2 = -4 - 2 = -6
Guided Practice
1 -6 ( -5 ) + 12 = 30 + 12
= 42
2 3 ( -6 ) - 3 = -18 - 3
= -21
3 -2 ( 8 ) + 7 = -16 + 7
= -9
4 4 ( -13 ) + 20 = -52 + 20
= -32
5 -4 ( 0 ) - 4 = 0 - 4
= -4
6 -3 ( -5 ) - 16 = 15 - 16
= -1
7 7 ( -5 ) + 20 = -35 + 20
= -15
15 dollars less
8 7 ( -10 ) + ( -100 ) = -70 + ( -100 )
= -170
170 fewer points
9 6 ( -4 ) + 10 = -24 + 10
= -14
Ned lost 14 points
10 4 ( -12 ) + 10 = -48 + 10
= -38
$38 less
11 -3 ( -2 ) + 3 = 6 + 3
= 9
3 ( -4 ) + 9 = -12 + 9
= -3
9 gt -3
-3 ( -2 ) + 3 gt 3 ( -4 ) + 9
12 -8 ( -2 ) -20 = 16 -20
= -4
3 ( -2 ) + 2 = - 6 + 2
= -4
-4 = -4
-8 ( -2 ) -20 = 3 ( -2 ) + 2
13 -7 ( 5 ) - 9 = -35 - 9
= -44
-3 ( 20 ) + 10 = -60 + 10
= -50
-44 gt -50
-7 ( 5 ) -9 gt -3 ( 20 ) + 10
14 -16 ( 0 ) -3 = 0 -3
= -3
-8 ( -2 ) -3 = 16 -3
= 13
-3 lt 13
-16 ( 0 ) -3 lt -8 ( -2 ) -3
15 A negative number usually represents a debt
payment or loss or a change that is a decrease
such as to a savings account
Independent Practice
16 -12 ( -3 ) + 7 = 36 + 7
= 43
17 -42 divide ( -6 ) + 5 -8 = 7 + 5 -8
= 12 -8
= 4
18 10 ( -60 ) -18 = -600 -18
= -618
19 ( -11 ) ( -7 ) + 5 - 82 = 77 + 5 - 82
= 82 - 82
= 0
20 35 divide ( -7 ) + 6 = -5 + 6
= 1
21 -13 ( -2 ) - 16 - 8 = 26 - 16 - 8
= 10 - 8
= 2
22 a 5 ( 2 ) -12 + 3 = 10 -12 + 3
= -2 + 3
= 1
b -3 ( 2 ) -1 + 6 + 7 = -6 -1 + 6 + 7
= -7 + 6 + 7
= -1 + 7
= 6
c Rose has more points than Lily so Rose won
the game
23 5 ( -4 ) -8 = -20 - 8 = -28
24 -36 divide ( -4 ) + 9 = 9 + 9 = 18
Copyright copy by Houghton Mifflin Harcourt 8 All rights reserved
25 a 4 ( -35 ) -9 = -140 -9
= -149
$149 less
b Yes $200 - $149 = $51 $51 gt $50 so Arleen
has enough money
26 a 2 ( -10 ) + 3 = -20 + 3= -17
b 7 + 2 + ( -7 ) = 2
c Warren since 2 is greater than -17
d Sample answer 2 of clubs 2 of spades
3 of spades king of diamonds 10 of clubs
7 of clubs
Focus on Higher Order Thinking
27 Sample answer Ann bought three shirts for $7 each
and a pair of pants for $10 Her mother gave her
$25 By how much did the amount of money Ann
had change
28 Disagree the quotient of two integers is positive if
the integers have the same sign So the first two
integers could have been negative integers
29 5 feet equals 60 inches so Lisa is holding the rock
60 inches above the waterrsquos surface The rock will
travel 4 times -5 = -20 inches or 20 inches below the
surface in 4 seconds 60 + 20 = 80 inches
MODULE 2
Ready to Go On
1 Since the numbers have opposite signs the product
will be negative
( -2 ) ( 3 ) = -6
2 Since the numbers have the same sign the product
will be positive
( -5 ) ( -7 ) = 35
3 Since the numbers have the opposite signs the
product will be negative
( 8 ) ( -11 ) = -88
4 ( -3 ) ( 2 ) ( -2 ) = ( -6 ) ( -2 ) = 12
5 5 ( -3 ) = -15 -15degC
6 -63 ____ 7 = -9
7 -15 ____ -3
= 5
8 0 ____ -15
= 0
9 96 ____ -12
= -8
10 -24 divide 6 = -4 -4 Ib
11 ( -4 ) ( 5 ) + 8 = -20 + 8
= -12
12 ( -3 ) ( -6 ) -7 = 18 -7
= 11
13 -27 ____ 9 - 11 = -3 - 11
= -14
14 -24 ____ -3
- ( -2 ) = 8 + 2
= 10
15 Sample answer Maurice lost 3 nickels in the laundry
and found 1 dime in the couch By how much did the
amount of money he had change
( -3 ) ( 5 ) + 10 = -15 + 10 = -5 He had $05 less
than before
Copyright copy by Houghton Mifflin Harcourt 9 All rights reserved
MODULE 3 Rational Numbers
Are You Ready
1 9 ___ 14
times 7 __ 6 =
3
2
9 ___ 14
times 7 __ 6 1
2
= 3 __ 4
2 3 __ 5 times 4 __
7 = 12 ___
35
3 11 ___ 8
times 10 ___ 33
= 1
4
11 ___ 8 times 10 ___
33 5
3
= 5 ___ 12
4 4 __ 9 times 3 =
3
4 __ 9 times 3 __
1 1
= 4 __ 3 or 1 1 __
3
5 1 __ 2 divide 1 __
4 = 1 __
2 times 4 __
1
=
1 1 __ 2 times 4 __
1 2
= 2 __ 1 = 2
6 3 __ 8 divide 13 ___
16 = 3 __
8 times 16 ___
13
= 1 3 __ 8 times 16 ___
13 2
= 6 ___ 13
7 2 __ 5 divide 14 ___
15 = 2 __
5 times 15 ___
14
= 1
1 2 __ 5 times 15 ___
14 3
7
= 3 __ 7
8 4 __ 9 divide 16 ___
27 = 4 __
9 times 27 ___
16
= 1
1 4 __ 9 times 27 ___
16 3
4
= 3 __ 4
9 3 __ 5 divide 5 __
6 = 3 __
5 times 6 __
5
= 18 ___ 25
10 1 __ 4 divide 23 ___
24 = 1 __
4 times 24 ___
23
= 1 1 __ 4 times 24 ___
23 6
= 6 ___ 23
11 6 divide 3 __ 5 = 6 __
1 times 5 __
3
= 2
6 __ 1 times 5 __
3 1
= 10 ___ 1 = 10
12 4 __ 5 divide 10 = 4 __
5 times 1 ___
10
= 2
4 __ 5 times 1 ___
10 5
= 2 ___ 25
13 21 - 6 divide 3
21 - 2
19
14 18 + ( 7 - 4 ) times 3
18 + 3 times 3
18 + 9
27
15 5 + ( 8 - 3 ) 2
5 + ( 5 ) 2
5 + 25
30
16 9 + 18 divide 3 + 10
9 + 6 + 10
15 + 10
25
17 60 - ( 3 - 1 ) 4 times 3
60 - ( 2 ) 4 times 3
60 - 16 times 3
60 - 48
12
18 10 - 16 divide 4 times 2 + 6
10 - 4 times 2 + 6
10 - 8 + 6
2 + 6
8
LESSON 31
Your Turn
0 _
571428
4 7 ⟌ _
40000000 Dividing into 40
_ -35
50
_ -49
10
_ -7
30
_ -28
20
_ -14
60
_ -56
40 Second appearance of 40
Because the number 40 repeats during the division
process the answer is a repeating decimal
-0 _
571428 or -0571428571428hellip
Copyright copy by Houghton Mifflin Harcourt 10 All rights reserved
0 _ 3
5 3 ⟌ _
100 Dividing into 10
_ -3
10 Second appearance of 10
Because the number 10 repeats during the division
process the answer is a repeating decimal 0 _ 3 or
0333hellip
045
6 20 ⟌ _
900
_ -8 0
1 00
_ -1 00
0
-045
7 -2 3 __ 4 = -thinsp 4 times 2 + 3
_________ 4 = -11 ____
4
275
4 ⟌ _
1100
_ -8
30
_ -28
20
_ -20
0
-275 terminating
8 7 1 __ 3 =
3 times 7 + 1 _________
3 = 22 ___
3
7 _ 3
3 ⟌ _
2200 Dividing into 10
_ -21
1 0 Second appearance of 10
Because the number 10 repeats during the division
process the answer is a repeating decimal 7 _ 3 or
7333hellip repeating
Guided Practice
06
1 5 ⟌ _
30
_ -3 0
0
06 terminating
089
2 100 ⟌ _
8900
_ -80 0
9 00
_ -9 00
0
-089 terminating
3 Simplify the fraction
4 ___ 12
= 4 times 1 _____ 4 times 3
= 1 __ 3
0 _ 3
3 ⟌ _
100 Dividing into 10
_ -3
10 Second appearance of 10
Because the number 10 repeats during the division
process the answer is a repeating decimal 0 _ 3 or
0333hellip repeating
0 _
25
4 99 ⟌ _
25000 Dividing into 25
_ -19 8
520
_ -495
25 Second appearance of 25
Because the number 25 repeats during the division
process the answer is a repeating decimal 0 _
25 or
02525hellip repeating
0 _ 7
5 9 ⟌ _
700 Dividing into 70
_ -63
70 Second appearance of 70
Because the number 70 repeats during the division
process the answer is a repeating decimal 0 _ 7 or
-0777hellip repeating
036
6 25 ⟌ _
900
_ -7 5
1 50
_ -1 50
0
-036 terminating
004
7 25 ⟌ _
100
_ -1 00
0
004 terminating
01420 _
45
8 176 ⟌ _
250000000
_ -17 6
7 40
_ -7 04
360
_ -352
80
_ -0
800 First appearance of 800
_ -704
960
_ -880
800 Second appearance of 800
Because the number 800 repeats during the
division process the answer is a repeating decimal
-01420 _
45 or -014204545hellip repeating
0012
9 1000 ⟌ _
12000
_ -10 00
2 000
_ -2 000
0
0012 terminating
Copyright copy by Houghton Mifflin Harcourt 11 All rights reserved
10 -11 1 __ 6 = -thinsp 6 times 11 + 1
_________ 6 = -67 ____
6
111 _ 6
6 ⟌ _
67000
_ -6
07
_ -6
1 0
_ -6
40 First appearance of 40
_ -36
40 Second appearance of 40
Because the number 40 repeats during the division
process the answer is a repeating decimal
- 67 ___ 6
-111 _ 6 or -111666hellip
11 2 9 ___ 10
= 10 times 2 + 9
__________ 10
= 29 ___ 10
29
10 ⟌ _
290
_ -20
9 0
_ -9 0
0
29 ___ 10
29
12 -8 23 ____ 100
= - 100 times 8 + 23
____________ 100
= -823 _____ 100
823
100 ⟌ _
82300
_ -800
23 0
_ -20 0
3 00
_ -3 00
0
-823 _____ 100
-823
13 7 3 ___ 15
= 15 times 7 + 3
__________ 15
= 108 ____ 15
72
15 ⟌ _
1080
_ -105
3 0
_ -3 0
0
108 ____ 15
72
14 54 3 ___ 11
= 11 times 54 + 3
__________ 11
= 597 ____ 11
54 _
27
11 ⟌ _
597000
_ -55
47
_ -44
30 First appearance of 30
_ -22
80
_ -77
30 Second appearance of 30
Because the number 30 repeats during the division
process the answer is a repeating decimal
597 ____ 11
54 _
27 or 542727hellip
15 -3 1 ___ 18
= -thinsp 18 times 3 + 1 __________
18 = -55 ____
18
30 _ 5
18 ⟌ _
55000
_ -54
1 0
_ -0
1 00 First appearance of 100
_ -90
100 Second appearance of 100
Because the number 100 repeats during the division
process the answer is a repeating decimal
-55 ____ 18
-30 _ 5 or -30555hellip
16 3 2 __ 3 =
3 times 3 + 2 _________
3 = 11 ___
3
3 _ 6
3 ⟌ _
1100
_ -9
2 0 First appearance of 20
_ -1 8
20 Second appearance of 20
Because the number 20 repeats during the division
process the answer is a repeating decimal
3 _ 6 or 3666hellip lbs of apples
17 -2 7 __ 8 = -
8 times 2 + 7 _________
8 = -23 ____
8
2875
8 ⟌ _
23000
_ -16
7 0
_ -6 4
60
_ -56
40
_ -40
0
-2875 lb
18 Disagree the definition of a rational number is a
number that can be written as the ratio of two
integers with a denominator not equal to zero and
3 ___ 47
is a well-defined ratio of two integers Tom did
not divide long enough to correctly determine that
the quotient is a repeating decimal
Copyright copy by Houghton Mifflin Harcourt 12 All rights reserved
Independent Practice
19 basketball players
_______________ football players
= 5 ___ 11
0 _
45
11 ⟌ _
5000 Dividing into 50
_ -4 4
60
_ -55
50 Second appearance of 50
Because the number 50 repeats during the division
process the answer is a repeating decimal
5 ___ 11
0 _
45 or 04545hellip repeating
20 hockey players
______________ lacrosse players
= 6 ___ 10
06
10 ⟌ _
60
_ -6 0
0
6 ___ 10
06 terminating
21 polo players
_____________ football players
= 4 ___ 11
036
11 ⟌ _
4000 Dividing into 40
_ -3 3
70
_ -66
40 Second appearance of 40
Because the number 40 repeats during the division
process the answer is a repeating decimal
4 ___ 11
0 _
36 or 03636hellip repeating
22 lacrosse players
______________ rugby players
= 10 ___ 15
= 5 times 2 _____ 5 times 3
= 2 __ 3
0 _ 6
3 ⟌ _
200 Dividing into 20
_ -1 8
20 Second appearances of 20
Because the number 20 repeats during the division
process the answer is a repeating decimal
10 ___ 15
0 _ 6 or 0666hellip repeating
23 football players
_____________ soccer players
= 11 ___ 11
= 1
11 ___ 11
1 terminating
24 Agree Sample answer There are 10 players on the
lacrosse team and dividing the number of any other
team by 10 will simply move the decimal point one
digit to the left Therefore the ratio of any team over
the lacrosse team will be a decimal that terminates
one place to the right of the decimal point
25 a -4 7 __ 8 = -thinsp 8 times 4 + 7
_________ 8 = - 39 ___
8
b 4875
8 ⟌ _
39000
_ -32
7 0
_ -6 4
60
_ -56
40
_ -40
0
-4875
c Sample answer 4 7 __ 8 is very close to 5 Therefore
You could estimate that the water level changes
by 5 inches per month The total change in the
water level at the end of the 3-month period
would be approximately -15 inches
26 integer terminating
27 Ben is taller because Benrsquos height of 5 5 ___ 16
is equal
to 85 ___ 16
or 53125 ft while Marcusrsquo height of 5 7 ___ 24
is
equal to 127 ____ 24
or 52916hellip ft
28 The first store has the better deal because they
offer 3 __ 4 or 075 of a bushel for $9 while the second
store offers only 2 __ 3 or 0666hellip of a bushel for $9
Focus on Higher Order Thinking
29 When the number 1 is the denominator in a fraction
its decimal form is simply the numerator In all other
cases concerning numbers 1 to 10 the division
process stops when either the remainder is 0 or
when the digits begin to repeat When the numbers
2 4 5 or 8 are in the denominator the decimal form
of a fraction will terminate When the numbers
3 6 7 or 9 are in the denominator the decimal form
of a fraction will be a repeating decimal
30 Julie made a higher score on her math test since
her math test score of 21 ___ 23
is equal to a repeating
decimal of approximately 0913 while her science
test score of 29 ___ 32
is equal to a terminating decimal of
090625
Sample answer The difference in scores cannot be
determined by simply comparing the numerators of
the two fractions because the denominators are not
the same For Julie to compare her scores she
needs to divide the denominators into their respec-
tive numerators until one of the quotients is found to
be greater than the other
31 No although the digits in the decimal appear to
follow a pattern a repeating decimal must have the
same combination of digits that repeat such as
0121212hellip
Copyright copy by Houghton Mifflin Harcourt 13 All rights reserved
LESSON 32
Your Turn
2
50 1 2 3 4
3 + 1 1 __ 2 = 4 1 __
2
3
0-7 -6 -5 -4 -3 -2 -1
-25 + ( -45 ) = -7
6
0 1 2-5-6-7-8 -4 -3-2-1
-8 + 5 = -3
7
10-1
1 __ 2 + ( - 3 __
4 ) = - 1 __
4
8
3 4 5 6 7 80 1 2-3-2-1
-1 + 7 = 6
9
3 4 50 1 2-5-4 -3-2-1
2 1 __ 2 + ( -2 1 __
2 ) = 0
10
3 4 50 1 2-5-4 -3-2-1
-45 + 45 = 0
11
1-1 0
3 __ 4 + ( - 3 __
4 ) = 0
The overall change is 0 cups
12 -15 + 35 + 2
-15 + 55
55 - 15
4
13 3 1 __ 4 + ( -2 ) + ( -2 1 __
4 )
3 1 __ 4 + ( -4 1 __
4 )
3 1 __ 4 - 4 1 __
4
-1
14 -275 + ( 325 ) + 5
-6 + 5
-1
15 15 + 8 + ( -3 )
23 + 3
20
Guided Practice
1
3 4 50 1 2-5-4 -3-2-1
-3 + ( -15 ) = -45
2
0 54321-5-4-3-2-1
15 + 35 = 5
3
0 105-1 -05
1 __ 4 + 1 __
2 = 3 __
4
4
0 54321-5-4-3-2-1
-1 1 __ 2 + ( -1 1 __
2 ) = -3
5
0 54321-5-4-3-2-1
3 + ( -5 ) = -2
6
0 54321-5-4-3-2-1
-15 + 4 = 25
7 -2150 + 2150 = 0 $0
8 -874 + 874 = 0 $0
9 275 + ( -2 ) + ( -525 )
275 + ( -725 )
- ( 725 - 275 )
-45
10 -3 + 1 1 __ 2 + 2 1 __
2 = -3 + 4 = 1
11 124 + 92 + 1
-124 + 102
- ( 124 - 102 )
-22
12 -12 + 8 +13
-12 + 21
21 - 12
9
13 45 + ( -12 ) + ( -45 )
45 + ( -45 ) + ( -12 )
0 + ( -12 )
-12
14 1 __ 4 + ( - 3 __
4 ) = - ( 3 __
4 - 1 __
4 ) = - 2 __
4 = - 1 __
2
Copyright copy by Houghton Mifflin Harcourt 14 All rights reserved
15 -4 1 __ 2 + 2 = - ( 4 1 __
2 - 2 ) = -2 1 __
2
16 -8 + ( -1 1 __ 8 ) = -9 1 __
8
17 Start at -4 and move 6 units to the right
The sum is 2
Independent Practice
18 The opposite of +19 is -19
19 -$225 + $1500 = $1500 - $225 = $1275
20 -3525 m + ( -85 ) = -4375 m
21 4 3 __ 4 mi + ( -3 1 __
4 mi ) = 1 2 __
4 mi = 1 1 __
2 mi
22 1635 m + ( -05 m ) = 163 m above sea level
23 30 + 15 - 25 = 45 - 25 = 20 pts
24 January
Income - Expenses
$1205 - $129060
- ( $129060 - $1205 ) -$8560
February
Income - Expenses
$1183 - $134544
-($134544 - $1183)
-$16244
Kameh lost $8560 in January and $16244 in
February
25 June
Income - Expenses
$2413 - $210623
$30677
July
Income - Expenses
$2260 - $195850
$30150
August
Income - Expenses
$2183 - $184512
$33788
Kameh gained $30677 in June $30150 in July and
$33788 in August
26 First sum all the values in the Income column Then
sum all the values in the Expenses column Subtract
the total expenses from the total income Finally add
the $250 profit from December (not shown in the
table) to find the total profit or loss of the bakery by
the end of August
Income = $1205 + $1183 + $1664 + $2413
$2260 + $2183 = $10908
Expenses = $129060 + $134544 + $1664 +$210623 + $195850 + $184512
= $1020989
Profit = $10908 - $1020989 + $250
= $94811
27 -2 is the opposite or additive inverse of 2
28 a 7 ( 10 ) + 3 ( -15 ) = 70 - 45 = 25 pts
b 2 ( 10 ) + 8 ( -15 ) = 20 - 120 = -100 pts
c 10 + 10 + 10 + 10 + 10 + ( ndash15 ) + ( ndash15 ) + ( ndash15 ) +
( ndash15 ) + ( ndash15 ) or 5 ( 10 ) + 5 ( ndash15 )
Focus on Higher Order Thinking
29 The sum of two negative rational numbers is always
negative The sum of a negative rational number and
a positive rational number is negative if the absolute
value of the negative number is greater than that of
the positive number
30 Sample answer The student might have subtracted
the absolute values of the numbers
31 Yes 55 and -55 are opposites and -23 and 23
are opposites so the expression [ 55 + ( -23 ) ] +
( -55 + 23 ) can be viewed as the sum of two
opposites which is always 0
LESSON 33
Your Turn
1
-9 -8 -7 -6 -5 -4
-65 - 2 = -85
2
42 30-1 1
1 1 __ 2 - 2 = - 1 __
2
3
-10-9 -8 -7 -6 -5 -4 -3 -2 -1 0
-225 - 55 = -775
6
1 2-1 0
025 - ( -150 ) = 175
7
1-1 0
- 1 __ 2 - ( - 3 __
4 ) = 1 __
4
Guided Practice
1
1312111098765 14 15
5 - ( -8 ) = 13
2
-9 -8 -7 -6 -5 -4 -3
3 1 __ 2 - 4 1 __
2 = -8
Copyright copy by Houghton Mifflin Harcourt 15 All rights reserved
3
-15 -13 -11 -9 -5-7
-7 - 4 = -11
4
-6 -5 -4 -3 -2 -1 0 1
-05 - 35 = -4
5 -14 - 22 = -36
6 -125 - ( -48 )
-125 + 48
- ( 125 - 48 )
-77
7 1 __ 3 - ( - 2 __
3 ) = 1 __
3 + 2 __
3 = 1
8 65 - ( -14 ) = 65 + 14 = 79
9 - 2 __ 9
- ( -3 )
- 2 __ 9
+ 3
3 - 2 __ 9
2 9 __ 9 - 2 __
9
2 7 __ 9
10 24 3 __ 8
- ( -54 1 __ 8 )
24 3 __ 8
+ 54 1 __ 8
78 4 __ 8
78 1 __ 2
11 -1 m + ( 105 m ) = -15 m
15 m below sea level
12 -12 1 __ 2 + ( -5 ) = -17 1 __
2
17 1 __ 2
or 175 yards
13 Change in height = Starting height - ending height
533 ft - ( -10 ft ) = 533 ft + 10 ft = 543 ft
14 -4500 + (-3015) = -7515 $7515
15 Explain that she is supposed to start at positive 4 on
the number line then move 12 places to the left
because she is subtracting a positive number She
will end on the number -8 which is the answer
Independent Practice
16 -126degC - 75degC = -201degC
17 -2565 ft - 165 ft + 1245 ft = -297 ft
The diver is 297 ft below the surface
18 -9500 ft - ( -26000 ft ) = 16500 ft
19 29035 ft - ( -36198 ft ) = 65233 ft
70000 ft - ( -26000 ft ) = 96000 ft
Mars has the greater difference by
96000 ft - ( 65233 ft ) = 30767 ft
20 a -5degF + 78degF - 32degF
b 78degF - 32degF
c -5degF + 78degF - 32degF 78degF - 5degF - 32degF 78degF - 37degF = 41degF 78degF - 32degF = 46degF
21 a -$1258 + ( -$3072 ) = -$4330
b -$4330 + ( -$25 ) = -$6830
c $6830 since -$6830 + $6830 = 0
22 a No 4 times 52 in = 208 in
b 208 in - 20 in = 08 in more needed
23 a 5 ft - 72 ft + 22 ft
b 5 ft - 72 ft + 22 ft
5 ft + 22 ft - 72 ft
72 ft - 72 ft
= 0 ft because he moved the same distance
backward and forward
24 a Yes
$425 + $089 + $1099
= $1613 lt $20
b $20 - $1613 = $387 left over
Focus on Higher Order Thinking
25 The Commutative Property of Addition (CPA) could
be used to simplify the two terms that already have
a common denominator first
- 7 ___ 16
- 1 __ 4 - 5 ___
16 = ( - 7 ___
16 ) + ( - 1 __
4 ) + ( - 5 ___
16 )
( - 7 ___ 16
) + ( - 5 ___ 16
) + ( - 1 __ 4 ) by CPA
( -7 + ( -5 ) __________
16 ) + ( - 1 __
4 )
( -12 ____ 16
) + ( - 1 __ 4 )
( - 4 times 3 _____ 4 times 4
) + ( - 1 __ 4 )
( - 3 __ 4 ) + ( - 1 __
4 )
( -3 + ( -1 ) __________
4 )
( -4 ___ 4 ) = -1
26 Lowest -225degF + ( -12degF ) = -345degFHighest -195degF + ( -12degF ) = -315degF
27 Sample answer Yes because both numbers are
rational numbers each can be written as the ratio of
two integers for example a __ b
and c __ d
Both fractions
could be given a common denominator and then
one could then be subtracted from the other The
result would be a fraction which is a rational number
28 No Sample answer It is possible for the
difference of two negative numbers to be negative
[ -4 - ( -1 ) = -3 ] but it is also possible for the
difference to be positive [ -5 - ( -8 ) = 3 ]
Copyright copy by Houghton Mifflin Harcourt 16 All rights reserved
LESSON 34
Your Turn
1
-8 -7 -6 -5 -2 -1 0-4 -3
2 ( -35 ) = -7
2
-2 -1 0 1 2 3 4-4 -3
-3 ( -125 ) = 375
4 ( - 3 __ 4 ) ( - 4 __
7 ) ( - 2 __
3 ) = -
13 times 41 times 2 __________ 14 times 7 times 31
= - 1 times 1 times 2 _________ 1 times 7 times 1
= - 2 __ 7
5 ( - 2 __ 3 ) ( - 3 __
4 ) ( 4 __
5 ) = 2 times 31 times 41
__________ 13 times 41 times 5
= 2 times 1 times 1 _________ 1 times 1 times 5
= 2 __ 5
6 ( 2 __ 3 ) ( - 9 ___
10 ) ( 5 __
6 ) = -
12 times 93 times 51
____________ 13 times 210 times 63
= - 1 times 31 times 1 __________ 1 times 2 times 31
= - 1 __ 2
Guided Practice
1
-5 -2 -1 0-4 -3
5 ( - 2 __ 3 ) = 5 __
1 times ( - 2 __
3 )
= - 5 times 2 _____ 1 times 3
= - 10 ___ 3
= -3 1 __ 3
2
-1 -05 0-2 -15
3 ( - 1 __ 4 ) = 3 __
1 times - 1 __
4
= - 3 times 1 _____ 1 times 4
= - 3 __ 4
3
0 1 2-2 -1
-3 ( - 4 __ 7 ) = 3 __
1 times 4 __
7
= 3 times 4 _____ 1 times 7
= 12 ___ 7
= 1 5 __ 7
4
-2 -1 0 1 2 3 4-4 -3
- 3 __ 4 ( -4 ) = 3 __
4 times 4 __
1
= 3 times 41
______ 14 times 1
= 3 times 1 _____ 1 times 1
= 3 __ 1
= 3
5 4 ( -3 ) = -12
6 -18 ( 5 ) = -9
7 -2 ( -34 ) = 68
8 054 ( 8 ) = 432
9 -5 ( -12 ) = 6
10 -24 ( 3 ) = -72
11 1 __ 2 times 2 __
3 times 3 __
4 = ( 1 times 21
______ 12 times 3
) ( 3 __ 4 )
= ( 1 __ 3 ) ( 3 __
4 )
= 1
1 __ 3 times 3 __
4 1
= 1 __ 4
12 - 4 __ 7 ( -thinsp 3 __
5 ) ( - 7 __
3 ) = ( - 4 times 3 _____
7 times 5 ) ( - 7 __
3 )
= 12 ___ 35
( - 7 __ 3 )
= - 4
5 12 times 7 ______ 35 times 3
1
1
= - 4 times 1 _____ 5 times 1
= - 4 __ 5
13 ( - 1 __ 8 ) times 5 times 2 __
3 = ( - 1 __
8 ) times 5 __
1 times 2 __
3
= - 1 times 5 times 21
__________ 48 times 1 times 3
= - 1 times 5 times 1 _________ 4 times 1 times 3
= - 5 ___ 12
Copyright copy by Houghton Mifflin Harcourt 17 All rights reserved
14 ( - 2 __ 3
) ( 1 __ 2 ) ( - 6 __
7 ) = 2 times 1 times 62
__________ 13 times 21 times 7
= 1 times 1 times 2 _________ 1 times 1 times 7
= 2 __ 7
15 4 ( -350 ) = -14 or a $14 change in price
16 18 ( -100 ) = -1800 or a $1800 change
17 Sample answer Count the number of times there is
a negative sign If there are an even number of
negative signs then the final product will be positive
If there is an odd number of negative signs then the
final product will be negative
Independent Practice
18 a 6 ( -1998 ) Note that the change in her bank
account balance does not depend on the initial
amount
b 200 + 6 ( -1998 )
= 200 - 11988
= 8012 $8012
19 Sample answer Start at 0 then move 15 units to
the left (because 15 is negative in this case) 4 times
You are now on -6 Then because 4 is negative in
this case we want to move to the opposite of -6
which is 6
20 8 ( -3 1 __ 4 ) = -8 ( 13 ___
4 )
= - 1
8 __ 1 times 13 ___
4 1
= - 2 times 13 ______ 1 times 1
= - 26 ___ 1
-26 min At the same rate the watch will be
26 minutes behind after 8 weeks
21 3 ( -325 ) = -975 ft The change in depth is -975 ft
Therefore the submarine will be 975 below sea level
(below the surface)
22 5 + ( -3 ) ( 15 )
= 5 + ( -45 )
= 05 cups left
23 Matthew is incorrect Sample answer Matthew
should have said that multiplying by two negatives
is like multiplying the opposite of a positive twice
The opposite of a positive twice brings you back to
a positive
24 5 ( -15 ) = -75 min Therefore she will be late by
75 minutes or 1 hour and 15 minutes
25 Total score is
2 times ( 6 ) + 16 times ( 05 )
+ 7 times ( -05 ) + 2 times ( -15 )
= 12 + 8 - 35 - 3
= 20 - 65
= 135 pts
Focus on Higher Order Thinking
26 Temperature at 5 kilometers
= Temp at ground level + change in temp
= 12 + 5 ( -68 )
= 12 + ( -34 )
= -22degC
27 a b c d
+ + + +
+ + - +
+ - + +
- + + +
- - - +
- - + -
- + - -
+ - - -
28 If the product of two numbers is positive then the two
numbers must have the same sign either they are
both positive or both negative If the sum is negative
then at least one of the numbers must be negative
Therefore the two integers that add to -7 and multiply
to 12 must both be negative The negative paired
factors of 12 are -1 and -12 -2 and -6 and -3
and -4 Of those choices only -3 and -4 add to -7
LESSON 35
Your Turn
3 28 ___ -4
= - 28 ___ 4 = -07
4 -664 ______ -04
= 664 ____ 04
= 166
5 - 55 ___ 05
= - 55 ___ 5 = -11
6 -4256 _______ 112
= -38
The divers change in elevation was -38 feet
per minute
7 - 5 __
8 ___
- 6 __ 7 = - 5 __
8 divide - 6 __
7
= - 5 __ 8 times - 7 __
6
= 35 ___ 48
8 - 5 ___
12 ____
2 __ 3 = - 5 ___
12 divide 2 __
3
= - 5 ___ 12
times 3 __ 2
= - 15 ___ 24
= - 5 __ 8
Copyright copy by Houghton Mifflin Harcourt 18 All rights reserved
9 -4__5
___1__2 =-4__5divide1__
2
=-4__5times2__1
=-8__5
=-13__5
Guided Practice
1 072_____-09=-72___
9 =-08
2 -1__5
___7__5 =-1__
15times5
1__
7=-1times1_____
1times7=-1__7
3 56___-7=-56___7=-8
4 251____4 divide(-3__
8)=251____
4 times-8__
3
=-251times82________
14times3
=-251times2_______1times3
=-502____3
5 75____-1__5
=-75___1times5__
1=-75times5______
1times1=-375
6 -91____-13=91___
13=7
7 -3__7
___9__4 =-
13__7times4__93
=-1times4_____7times3
=-4___21
8 - 12____003
=-1200_____
3 =-400
9 =changeinwaterlevel_________________
changeindays
=-35L______4day
=-0875 L____day
or-0875Lperday
10 =totalchangeinprice_________________
changeindays
=-$4575________5day
=-$915perdayonaverage
11 totalchangeinaltitude___________________
numberofminutes
=-044mi________08min
=-44mi______8min
=-055mileperminute
12 FirstfindthesignofthenumeratorwhichisnegativeNextfindthesignofthedenominatorwhichisnegativeThereforethequotientwillbepositivebecausethenumeratoranddenominatorbothhavethesamesign
Independent Practice
13 5___-2__
8=-5__
1times8__
24
1=-5times4_____
1times1=-20
14 51__3divide(-11__
2)
=-3times5+1_________3 divide2times1+1_________
2
=-16___3divide3__
2
=-16___3times2__
3
=-16times2______3times3
=-32___9
15 -120_____-6 =120____
6 =20
16 -4__5
___-2__
3=
24__5times3__
21=2times3_____
5times1=6__
5
17 103divide(-103)=-103____1 times 1____
103
=-103times1________1times103
=-103____103
=-103____103
=-01
18 -04_____80
=-04___80
=-0005
19 1divide9__5=1__
1times5__
9=5__
9
20 -1___4 ___
23___24
=-1__
14times246
___23
=-1times6______1times23
=-6___23
21 -1035_______-23 =1035_____
23 =45
22 totalhours_____________numberofdays
= 21h______7days
=3 h____day
totaltimelost3 h____day
times3days=9hours
Alexusuallyruns21hoursperweeksodivideby7tofindthatheruns3hoursperdaySinceheisunabletorunfor3dayshistimeisdecreasedby9hoursor-9
23 totalchangeinyards
_________________numberofruns
=-4times15+3___________4 times1__
9
yd___run
=-763___4 times1__
91yd
___run
=-153__
4yd______
9runs
=-153__4times1__
9
yd___run
=-7__4or-13__
4yardsperrun
CopyrightcopybyHoughtonMifflinHarcourt 19 Allrightsreserved
DO NOT EDIT--Changes must be made through File info CorrectionKey=B
7_MCABESK207233_U1M03indd 19 103113 759 PM
24 -121degC + ( -78degC ) + ( -143degC ) + ( -72degC )
_____________________________________ 4
= 414degC ______ 4
= -1035degC per day
25 a total profit
_____________ number of days
= $1750
______ 7 days
= $250 per day
b $150
_____ day
times 7 days = $1050
c total change
_____________ number of days
= - $490
______ 7 days
= -$70 per day
26 total meters descended ___________________ number of seconds
= 996 m ______ 12 s
= 83 ms
27 When converting the division equation into a
multiplication problem he forgot to multiply by the
reciprocal and instead multiplied by the fraction in
the denominator The correct answer is given by
- 3 __
4 ___
4 __ 3
= - 3 __
4 times 3 __
4 = - 9 ___
16
28 -37 m _______ year times ( 2012 ndash 1995 ) years
= -37 m _______ year times 17 years
= -629 m
Focus on Higher Order Thinking
29 Sample answer The average change in temperature
per day would be given by -85 divide 15 if the
temperature were to drop of 85degF over 15 days
-85degF divide 15 d
= - 1785 ____ 315
degF __ d
= - 17 ___ 3 degF __
d or -5 2 __
3 degF __
d asymp -567 degF __
d
On average the temperature changed by -567degF
every day
30 Yes By definition the result of dividing an integer by
a non-zero integer is a rational number
31 Yes The result of dividing an integer by a non-zero
integer always results in a rational number by
definition
LESSON 36
Your Turn
1 Find the total commercial time
3 times 2 1 __ 2 = 7 1 __
2
Find the total entertainment time
30 - 7 1 __ 2 = 22 1 __
2
Find the length of each entertainment segment
22 1 __ 2 divide 4 = 5 5 __
8
Each entertainment segment is 5 5 __ 8 minutes long
2 Find the number of cups of sugar in the bag
454 divide 48 asymp 95
Find the number of 3 __ 4 -cup portions in the bag
95 divide 075 asymp 127
12 batches can be made from the bag of sugar
Find the cost of 1 batch
349 divide 12 asymp 029
The cost of the sugar is $029 per batch
3 Convert the percent to a decimal
12 3 __ 5 = 126
= 0126
Find the worth after 1 year
750 times 0126 = 945
750 + 945 = 8445
Find the worth after 2 years
8445 times 0126 asymp 10641
8445 + 10641 = 95091
Find the worth after 3 years
95091 times 0126 asymp 11981
95091 + 11981 = 107072
The stock is worth $107072
Guided Practice
1 45h times 3 1 __ 5 or 32 miles per hour = 144 miles
144 miles divide 3 3 __ 5 or 36 miles per hour = 4 hours
2 2568 inches times -002375 asymp -061 inches
2568 inches - 061 asymp 2507 inches
3 Sample answer Using a calculator to solve a
problem that involves complicated arithmetic can
help you avoid errors It can also help you to check
solutions to any problems you solved by hand
Independent Practice
4 Find the total weight
78 times 3 = 234
Find the weight each climber carries
234 divide 4 = 585
Each climber carries 585 kg
Copyright copy by Houghton Mifflin Harcourt 20 All rights reserved
5 Find the available width on the page
12 - 3 1 __ 2 = 8 1 __
2
Find half the width
8 1 __ 2 divide 2 = 4 1 __
4
He should put the picture 4 1 __ 4 inches from each side
of the page
6 Find the amount of cereal needed for all the children
11 times 1 __ 3 = 3 2 __
3
10 times 3 __ 4 = 7 1 __
2
3 2 __ 3 + 7 1 __
2 = 11 1 __
6
Compare the total needed with the amount in the
box
11 1 __ 6 lt 12
Yes there is enough Oaties for all the children The
amount needed is 11 1 __ 6 cups and that is less than the
amount in the box 12 cups
7 Find half of the distance that the referee walked
41 3 __ 4 divide 2 = 20 7 __
8
Find how far that distance is from the goal line
50 - 20 7 __ 8 = 29 1 __
8
The referee is 29 1 __ 8 feet from the nearest goal line
8 Donovanrsquos score was 39 ___ 50
= 78 Marcirsquos score was
( 78 + 10 ) = 88
9 Find the number Marci answered correctly
88 = 88 ____ 100
= 44 ___ 50
Find how many more that Marci answered than
Donovan
44 - 39 = 5
Marcie answered 5 more questions correctly than
Donovan
10 Sample answer Donovan got about 40 out of 50
questions right or about 80 Since Marci scored
10 more that is about 90 90 times 50 is 45 So
Marci answered about 45 - 40 or 5 more questions
correctly than Donovan
11 Yes -075 is a reasonable estimate
19 ___ 37
is about 1 __ 2 and 143 is about 15 and
15 times ( - 1 __ 2 ) = -075
12 Sample answer approximately -07343 Use a
calculator Divide -19 by 37 multiply the quotient by
143 then round the product
13 Sample answer Yes -07343 asymp - 075
Focus on Higher Order Thinking
14 Find the time of the descent
-79 9 ___ 10
divide ( -188 ) = 425
Find the time for the ascent
19 1 __ 8 - 1275 - 425 = 2 1 __
8
Find the distance of the ascent
-28 9 ___ 10
- ( -79 9 ___ 10
) = 51
Find the rate of the ascent
51 divide 2 1 __ 8 = 24
The diverrsquos rate of change in elevation during the
ascent was 24 ftmin
15 Sample answer
(1) Convert the mixed number 27 3 __ 5 to the decimal
276 find the sum of 276 and 159 then multiply
the result by 037
(2) Convert the mixed number 27 3 __ 5 to the decimal
276 Then use the Distributive Property so that
(276 + 159)037 = (276)(037) + (159)(037)
Multiply both 276 and 159 by 037 and add the
products I would use the first method because
there are fewer steps and so fewer chances to
make errors
16 Sample answer You need to know how many
gallons of paint you need to paint a wall Measure
the length and width of the wall with a yardstick
then find the area Use the calculator to divide the
area by the number of square feet a gallon of the
paint covers Round up rather than down to the
nearest gallon so you have enough paint
MODULE 3
Ready to Go On
1 4 1 __ 5 =
5 times 4 + 1 _________
5 = 21 ___
5
42
5 ⟌ _
210
_ -20
1 0
_ -1 0
0
42
Copyright copy by Houghton Mifflin Harcourt 21 All rights reserved
2 12 14 ___ 15
= 15 times 12 + 14
___________ 15
= 194 ____ 15
129 _ 3
15 ⟌ _
194000
_ -15
44
_ -30
14 0
_ -13 5
50 first 50
_ -45
50 second 50
Because the number 50 repeats during the division
process the answer is a repeating decimal
129 _ 3 or 12933
3 5 5 ___ 32
= 32 times 5 + 5
__________ 32
= 165 ____ 32
515625
32 ⟌ _
16500000
_ -160
5 0
_ -3 2
1 80
_ -1 60
200
_ -192
80
_ -64
160
_ -160
0
515625
4 45 + 71 = 116
5 5 1 __ 6 + ( -3 5 __
6 ) = 4
6+1 ____
6 -3 5 __
6
= 1 2 __ 6
= 1 1 __ 3
6 - 1 __ 8 -6 7 __
8 = - 1 __
8 + ( -6 7 __
8 )
= -6 8 __ 8
= -7
7 142 - ( -49 ) = 142 + 49
= 191
8 -4 ( 7 ___ 10
) = - 4 __ 1 times 7 ___
10
= - 24 times 7 _______ 1 times 105
= - 2 times 7 _____ 1 times 5
= - 14 ___ 5 or -2 4 __
5
9 -32 ( -56 ) ( 4 ) = 32 times 56 times 4
= 7168
10 - 19 ___ 2 divide 38 ___
7 = -
119 times 7 _______ 2 times 382
= - 1 times 7 _____ 2 times 2
= - 7 __ 4
11 -3201 _______ -33
= 3201 _____ 33
97
33 ⟌ _
3201
_ -297
23 1
_ -23 1
0
97
12 Add the initial stock price with the increase from the
second day
$8360 + $1535 = $9895
Convert the percent decrease to a decimal
-4 3 __ 4 = -475 or -00475
Multiply the price on the second day times the
percent decrease and then subtract the result from
the price on the second day to find the final stock
price
$9895 times -00475 asymp -$47
$9895 - $47 = $9425
The final stock price is $9425 Yes this is
reasonable price on day 1 asymp $85 price on day
2 asymp $100 So the price on day 3 asymp $95
13 Sample answer You can use negative numbers to
represent temperatures below zero or decreases in
prices
Copyright copy by Houghton Mifflin Harcourt 22 All rights reserved
MODULE 4 Ratios and Proportionality
Are You Ready
1 3 __ 4 divide 4 __
5 = 3 __
4 times 5 __
4
= 15 ___ 16
2 5 __ 9 divide 10 ___
11 = 5 __
9 times 11 ___
10
= 1
5 __ 9 times 11 ___
10 2
= 11 ___ 18
3 3 __ 8 divide 1 __
2 = 3 __
8 times 2 __
1
= 4
3 __ 8 times 2 __
1 1
= 3 __ 4
4 16 ___ 21
divide 8 __ 9 = 16 ___
21 times 9 __
8
=thinsp 2
7 16 ___ 21
times 9 __ 8 3
1
= 6 __ 7
5 B ( -4 1 )
6 C ( 3 0 )
7 D ( 5 4 )
8 E ( -2 -2 )
9 F ( 0 0 )
10 G ( 0 -4 )
LESSON 41
Your Turn
3 1 __ 6 acre divide ( 1 __
4 hour ) = 1 __
6 times 4 __
1
= 3
1 times 4 _____ 6 times 1
2
= 1 times 2 _____ 3 times 1
= 2 __ 3 acre per hour
4 3 cups divide ( 3 __ 4 cups ) = 3 __
1 divide 3 __
4
= 3 __ 1 times 4 __
3
= 1
3 times 4 _____ 1 times 3
1
= 1 times 4 _____ 1 times 1
= 4 cups
5 Jaylan 3 __ 4 divide 1 __
5 = 3 __
4 times 5 __
1 = 15 ___
4 = 3 3 __
4
Wanchen 2 __ 3 divide 1 __
6 = 2 ___
1 3 times 6
2 __
1 = 4 __
1 = 4
Jaylanrsquos unit rate is 3 3 __ 4 cups of water per cup of lime
juice Wanchenrsquos unit rate is 4 cups of water per cup
of lime juice Wanchenrsquos limeade has a weaker lime
flavor because 4 gt 3 3 __ 4 and the limeade with a
greater ratio of water to lime juice will have a weaker
flavor
Guided Practice
1
Distance (mi) 8 1 __ 2 17 25 1 __
2 34 42 1 __
2
Time (h) 1 __ 2 1 1 1 __
2 2 2 1 __
2
2 3 1 __ 2 miles divide ( 1 1 __
4 hours ) = 7 __
2 divide 5 __
4 mi ___ h
= 7 times 4 _____ 2 times 5
= 1 7 times 4 _____ 2 times 5
2
= 7 times 2 _____ 1 times 5
= 14 ___ 5 mi ___
h
= 2 4 __ 5 miles per hour
3 5 __ 8 page divide ( 2 __
3 minute ) = 5 __
8 times 3 __
2
= 15 ___ 16
page per minute
4 1 __ 6 foot divide ( 1 __
3 hour ) = 1 __
6 times 3 __
1
= 2 1 times 3 _____ 6 times 1
1
= 1 times 1 _____ 2 times 1
= 1 __ 2 foot per hour
5 5 __ 8 sq ft divide ( 1 __
4 hour ) = 5 __
8 times 4 __
1
= 2 5 times 4 _____ 8 times 1
1
= 5 times 1 _____ 2 times 1
= 5 __ 2 or 2 1 __
2 square feet per hour
Solutions KeyRatios and Proportional Relationships
UNIT
2
Copyright copy by Houghton Mifflin Harcourt 23 All rights reserved
6 240 milligrams divide ( 1 __ 3 pickle ) = 240 ____
1 divide 1 __
3
= 240 ____ 1 times 3 __
1
= 720 ____ 1
Brand Arsquos rate is 720 mg per pickle
325 milligrams divide ( 1 __ 2 pickle ) = 325 ____
1 divide 1 __
2
= 325 ____ 1 times 2 __
1
= 650 ____ 1
Brand Brsquos rate is 650 milligrams per pickle and is
therefore lower than Brand A
7 The unit rate for Ingredient C is
1 __ 4 cup divide ( 2 __
3 serving ) = 1 __
4 times 3 __
2
= 3 __ 8
cup _______
serving
The unit rate for Ingredient D is
1 __ 3 cup divide ( 3 __
4 serving ) = 1 __
3 times 4 __
3
= 4 __ 9
cup _______
serving
To compare 3 __ 8 to 4 __
9 find the least common
denominator of 8 and 9 so that 3 __ 8 = 27 ___
72 and 4 __
9 = 32 ___
72
Therefore ingredient Crsquos unit rate is lower
8 Divide the number in the numerator by the number
in the denominator Write the result with the units of
the rate
For example 1 mile ______
1 __ 2 hour
= 1 __
1 __ 2 = 2 miles per hour
Independent Practice
9 a The unit rate in dollars per hour for On Call is
$10 divide ( 35 hours ) = 10 ___ 35
$ __
h asymp $286 per hour
The unit rate in dollars per hour for Talk Time is
$125 divide ( 1 __ 2 hours ) = 125 ____
05 $ __
h asymp $250 per hour
b Talk Time offers the better deal because its rate in
dollars per hour is lower
c To convert dollars per minute to dollars per hour
multiply by 60
$005 divide ( 1 minute )
= 005 ____ 1
$ ____
min times 60 min ______
1 h
= $3 per hour
d $3 per hour is more expensive than either On Call
or Talk Time so it is not a better deal than either
one
10 a Sample answer 1 __ 2 cup dried fruit to 1 __
8 cup
sunflower seeds in a granola recipe
b The ratio would not change if the recipe were
tripled because both numbers in the ratio would
be multiplied by the same number and therefore
the ratio would still be equivalent to what it was
originally
c 1 __ 2 divide 1 __
8 = 1 ___
1 2 times 8
4 __
1 = 4 __
1 = 4
Sample answer 4 cups dried fruit per 1 cup
sunflower seeds
11 10 songs
____________ 2 commercials
= 5 songs ____________
1 commercials
12 a Terrancersquos rate
6 mi divide ( 1 __ 2 h ) = 6 __
1 times 2 __
1
= 12 miles per hour
Jessersquos rate
2 mi divide ( 15 min ) = 2 __ 1 divide 1 __
4
= 2 __ 1 times 4 __
1 mi ___ h
= 8 miles per hour
b Terrance
50 mi divide ( 12 mi ___ h ) = 50 ___
1 times 1 ___
12
= 50 ___ 12
h
= 4 1 __ 6 h
= 4 10 ___ 60
h
= 4 hours and 10 minutes
Jesse
50 mi divide ( 8 mi ___ h ) = 50 ___
1 times 1 __
8
= 50 ___ 8 h
= 6 1 __ 4 h
= 6 15 ___ 60
h
= 6 hours and 15 minutes
c 8 mi divide ( 45 min ) = 8 __ 1 divide 3 __
4
= 8 __ 1 times 4 __
3
= 32 ___ 3
= 10 2 __ 3 miles per hour
Sandrarsquos unit rate is greater than Jessersquos but
lower than Terrancersquos so she runs slower than
Terrance but faster than Jesse
13 1 ___ 10
h = 6 ___ 60
h = 6 min
300 words _________ 6 min
= 50 words per min
1 ___ 12
h = 5 ___ 60
h = 5 min
300 words _________ 5 min
= 60 words per min
Faster Eli typed 50 words per minute in his first test
and 60 words per minute in his second test
Copyright copy by Houghton Mifflin Harcourt 24 All rights reserved
Focus on Higher Order Thinking
14 a For the 10-pack of 21 ounce bars
$1537 divide 10 bars asymp $154 per bar
For the 12-pack of 14 ounce bars
$1535 divide 12 bars asymp $128 per bar
The 12-pack has the better price per bar
b For the 10-pack
$1537 divide ( 10 times 21 oz ) = 1537 divide 21
asymp $073 per ounce
For the 12-pack
$1535 divide ( 12 times 14 oz ) = 1535 divide 168
asymp $091 per ounce
The 10-pack has a better price per ounce
c Sample answer Since I always eat them one bar
at a time the 12-pack is the better choice
15 Yes Half a room in half a day corresponds to a unit
rate of 1 __ 2 room divide ( 1 __
2 day ) = 1 room _____
day so at the same
rate the painter could paint 7 rooms in 7 days
16 Sample answer Take the reciprocal of the rate For
example a rate of 7 gallons per hour is equal to
1 hour per 7 gallons
LESSON 42
Your Turn
3 No the rates are not equal and therefore her speed
was not constant
4 Since the ratio of students to adults is constant the
relationship between them is proportional
students ________ adults
= 12 ___ 1 = 36 ___
3 = 60 ___
5 = 12 students per adult
If s = the number of students and a = the number
of adults then a = 1 ___ 12
s or s = 12a
Guided Practice
1 45 ___ 1 = 45 90 ___
2 = 45 135 ____
3 = 45 180 ____
4 = 45
The relationship is proportional
2 k = y __ x = 10 ___
2 = 5 y = 5x
3 k = y __ x = 2 __
8 = 1 __
4 y = 1 __
4 x
4 With the equation y = kx where k is the constant
of proportionality
Independent Practice
5 k = y __ x = 74 ___
4 = 1850 y = 1850x
6 $1099
_______ 05 days
= $2198 per day
7 Rent-All because it has the lowest price per day
($1850)
8 100 ft _____ 08 s
= 1000 _____ 8 ft __ s = 125 ft __ s
500 ft _____ 31 s
= 5000 _____ 31
ft __ s asymp 1613 ft __ s
1875 ft ______ 15 s
= 1875 ______ 15
ft __ s asymp 125 ft __ s
No Emtiaz assumed the relationship is proportional
but it is not The rate of change is not constant and
so his answer is not reasonable
9 $3125
______ 5 h
= $625 per hour and $5000
______ 8 h
= $625 per
hour Because the two unit rates are the same the
relationship between charge and time is proportional
10 The constant rate of change in this context means
that Steven charges $625 per hour
11 y = $625x where x is the number of hours Steven
babysits and y is the amount Steven charges
12 y = $625 ( 3 ) = $1875
13 300 ft _____ 2 min
= 6750
_____ 45
= 150 feet per minute
150 ft _____ min
times 60 min ______ 1 h
= 9000 feet per hour
14 y = 150x
15 Sample answer Feet per minute A submarine may
stay submerged for hours but it would not dive for
hours
Focus on Higher Order Thinking
16 Yes because there is a proportional relationship
so the distance and the time would increase by the
same factor
17 Sample answer Yes Even though the rates in the
table are not constant per ear of corn due to
rounding there is a constant rate for every 3 ears
of corn
LESSON 43
Your Turn
1 No because 11 ___ 1 ne 16 ___
2 Also the line drawn through
the points does not go through the origin
5 a The point ( 4 60 ) represents that the bicyclist can
ride a distance 60 miles in 4 hours
b k = 60 mi _____ 4 h
= 15 mi ___ h
c y = 15x where x is time in hours and y is
distance in miles
Guided Practice
1
Time (h) 3 5 9 10
Pages 195 325 585 650
Proportional the rate is a constant 65 pages
per hour
2
Time (h) 2 3 5 8
Earnings 15 2250 3750 60
Proportional the rate of is a constant $750 per hour
Copyright copy by Houghton Mifflin Harcourt 25 All rights reserved
3 Not proportional the relationship is linear but a line
drawn connecting the points will not pass through
the origin of ( 0 0 )
4 Proportional a line can be drawn that passes
through the points and also the origin of ( 0 0 )
5 k = 28 ft ____ 8 s
= 7 __ 2 ft __ s = 35 ft __ s y = 7 __
2 x or y = 35x where
x = time in seconds and y = height in feet
6 k = $2 ______
8 items = 1 __
4
$ _____
items = 025
$ _____
items so y = 1 __
4 x or
y = 025x where x = number of items and
y = cost in dollars
7 The graph is a straight line passing through the
origin
Independent Practice
8 It is the distance ( 0 miles ) that each horse runs in
0 minutes
9 Horse A runs 1 mile in 4 minutes
Horse B runs 1 mile in 25 minutes
10 For Horse A y = 1 __ 4 x
For Horse B y = 1 ___ 25
x or 2 __ 5 x
11 If x is time in minutes and y is distance in miles in
12 minutes Horse A will run 3 miles or 1 __ 4 ( 12 ) = 3
and Horse B will run 48 miles or 2 __ 5 ( 12 ) = 24 ___
5 = 48
12 Students may draw any straight line with a slope
steeper than 2 __ 5 that starts at the origin of ( 0 0 ) An
example is given below
2
2
4
6
8
10
4 6 8 10Time (min)
Dis
tanc
e (m
i)
A
B
O
13 Yes if the train is traveling at a constant speed the
ratio of miles traveled to time in hours will be
constant and therefore a graph comparing miles to
hours will form a straight line that passes through
the origin of ( 0 0 )
14 Sample answer When comparing relationships that
may be easier to observe on a graph than in an
equation
15 a
2
8
16
24
32
40
4 6 8 10DVDs
Cost
($)
O
b Sample answer The graph will pass through the
point ( 4 20 ) This point shows that four DVDs will
cost $20
16 The graph passes through the point ( 4 8 ) so
Glenda swam 8 feet in 4 seconds
17 Yes The graph is linear and passes through the
origin and therefore the rate of distance to time is
proportional at each point on the line
18 k = 8 ft ___ 4 s
= 2 ft __ s so y = 2x where x is time in
seconds and y is distance swam in feet It would
take 22 minutes to swim 1 __ 2 mile at this rate
Focus on Higher Order Thinking
19 Divide the second coordinate by the first to find the
constant of proportionality k Substitute the value of
k into the equation y = kx Then choose a value for x
and solve for y to find the ordered pair
20 Car 3 is not traveling at a constant speed
because 65 ___ 1 ne 85 ___
2
21 Since Car 4 is traveling at twice the speed it will
travel twice the distance as Car 2 in the same
amount of time Therefore the values in Car 4rsquos
distance column will be twice that shown in Car 2rsquos
distance column
MODULE 4
Ready to Go On
1 $140
_____ 18 ft 2
= $778 per square foot
2 $299
_____ 14 lb
asymp $021 per pound
3 $56 ______
25 gal = $224 per gallon
$3205
______ 15 gal
asymp $214 per gallon this is the better deal
4 $160
_____ 5 g
= $3200 per gram this is the better deal
$315
_____ 9 g
asymp $3500 per gram
5 No The ratio of dollars earned to lawns mowed is
not constant 15 ___ 1 ne 48 ___
3
Copyright copy by Houghton Mifflin Harcourt 26 All rights reserved
6 k = $9
___ 8euro
= $27 ____
24euro = 9 __
8 $ __
euro or 1125
$ __
euro So y = 9 __
8 x or
y = 1125x where x equals the number of euros
and y equals their value in dollars
7 The graph passes through the point ( 2 5 )
so k = 5 __ 2 servings
_______ pt
or k = 25 servings
_______ pt
Therefore
y = 5 __ 2
x or y = 25x where x equals the number
of pints and y equals the number of servings
8 The new graph will pass through the points ( 0 0 ) and ( 3 2 )
2
2
4
6
8
10
4 6 8 10Pints
Serv
ings
Frozen Yogurt
O
Therefore y = 2 __ 3 x where x equals the number of
pints and y equals the number of servings
9 Sample answer Compare corresponding values of
the variables to determine whether there is a
constant rate
Copyright copy by Houghton Mifflin Harcourt 27 All rights reserved
MODULE 5 Proportions and Percent
Are You Ready
1 22 = 22 ____ 100
= 022
2 75 = 75 ____ 100
= 075
3 6 = 6 ____ 100
= 006
4 189 = 100 + 89
= 100 ____ 100
+ 89 ____ 100
= 1 + 089
= 189
5 059 = 59
6 098 = 98
7 002 = 2
8 133 = 133
9 64
_ timesthinsp05
320
32
10 30
_ timesthinsp007
210
21
11 160
_ timesthinsp015
800
_ +1600
2400
24
12 62
_ timesthinsp032
124
_ +thinsp1860
1984
1984
13 4
_ timesthinsp12
8
_ +thinsp40
48
48
14 1000
_ timesthinsp006
6000
60
LESSON 51
Your Turn
2 x = ( $64 - 52 )
__________ $52
x = $12
____ $52
asymp 23
4 x = ( 18 - 12 )
________ 18
x = 6 ___ 18
asymp 33
5 x = ( 16 - 10 )
________ 16
x = 6 ___ 16
= 375
8 010 times $499 = $4990
$499 + $4990 = $54890
9 030 times $499 = $14970
$499 - $14970 = $34930
Guided Practice
1 x = ( $8 - $5 )
_________ $5
x = $3
___ $5
= 60
2 x = ( 30 - 20 )
_________ 20
x = 10 ___ 20
= 50
3 x = ( 150 - 86 )
__________ 86
x = 64 ___ 86
asymp 74
4 x = ( $389 - $349 )
______________ $349
x = $040
_____ $349
asymp 11
5 x = ( 14 - 13 )
________ 13
x = 1 ___ 13
asymp 8
6 x = ( 16 - 5 )
________ 5
x = 11 ___ 5 = 220
7 x = ( 64 - 36 )
_________ 36
x = 28 ___ 36
asymp 78
8 x = ( 80 - 64 )
_________ 80
x = 16 ___ 80
= 20
9 x = ( 95 - 68 )
_________ 95
x = 27 ___ 95
asymp 28
Copyright copy by Houghton Mifflin Harcourt 28 All rights reserved
10 x=( 90-45)_________
90
x=45___90
=50
11 x=( 145-132)__________
145
x=13____145
asymp9
12 x=( 64-21)_________
64
x=43___64
asymp67
13 x=( 16-0)________
16
x=16___16
=100
14 x=( 3-1__
2)_______
3
x=21__
2___
3 asymp83
15 010times$900=$090 $900+$090=$990
16 025times48=12 48-12=36cookies
17 020times340=68 $340-68=272pages
18 050times28=14 28+14=42members
19 004times$29000=$1160 $29000-$1160=$27840
20 130times810=1053 810+1053=1863songs
21 030times20=6 20+6=26miles
22 Dividetheamountofchangeinthequantitybytheoriginalamountthenexpresstheanswerasapercent
Independent Practice23
ItemOriginal
PriceNew Price
Percent Change
Increase or
DecreaseBike $110 $96 asympthinsp13 Decrease
Scooter $45 $56 asympthinsp24 Increase
TennisRacket $79 $8295 5 Increase
Skis $580 $435 25 Decrease
24 a 55
x=( 8-3)_______
8 =5__
8=625
x=( 12-7)________
12 =5___
12asymp417
Theamountofchangeisthesamebutthepercentofchangeislessfrom2010to2011
b Changewasgreatestbetween2009and2010
x=( 12-3)________
3
x=9__3=300increase
25 a Amountofchange=( 5-4)=1
Percentdecrease=1__5=20
b $100_____5 =$020each$100_____
4 =$025each
Amountofchange=$025-$020=$005
Percentincrease=$005_____$020
=25
26 Percenterror=( 136-133)___________
136 times100
=03____136
times100asymp2
Focus on Higher Order Thinking
27 a Theyhavethesame$100+$10=$110and$100+10( $100)=$110
b SylviahasmoreLeroihas$110+$10=$120andSylviahas$110+10( $110)=$121
c BecauseSylviawillhavemoreafterthesecondadditionaldepositandshewillbedepositingincreasingamountsshewillalwayshavemoreinheraccount
28 Thefinalamountisalways0becausea100decreaseofanyamountwouldbe0
29 NoOnlythefirstwithdrawalis$10Eachwithdrawalafterthatislessthan$10becauseitis10oftheremainingbalanceTherewillbemoneyleftafter10withdrawals
LESSON 52
Your Turn
2 a 1c+01c11c
b s=11times$28=$3080
3 a 200
b 1c+2c3c
5 a
1b - 024b
1b024b
b 1b-024b=076b
6 a 1p-005p095p
b 095p=$1425
CopyrightcopybyHoughtonMifflinHarcourt 29 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U2M05indd 29 103113 214 AM
Guided Practice
1 a 035s
b 1s + 035s 135s
c 135 times $3200 = $4320
d 035 times $3200 = $1120
Item Price Markup MarkupRetail
Price
2 Hat $18 15 $270 $2070
3 Book $2250 42 $945 $3195
4 Shirt $3375 75 $2531 $5906
5 Shoes $7499 33 $2475 $9974
6 Clock $4860 100 $4860 $9720
7 Painting $18500 125 $23125 $41625
8 $4500 - 022 ( $4500 ) = $3510
9 $8900 - 033 ( $8900 ) = $5963
10 $2399 - 044 ( $2399 ) = $1343
11 $27999 - 075 ( $27999 ) = $7000
12 Write the percent of markdown as a decimal
subtract the product of this decimal and the regular
price from the regular price
Independent Practice
13 a 046b
b 1b - 046b 054b
c 054 times $2900 = $1566
d 046 times $2900 = $1334
14 Regular Price $329
Sale Price $201
Regular Price $419
Sale Price $245
Regular Price $279
Sale Price $115
Regular Price $309
Sale Price $272
Regular Price $377
Sale Price $224
15 a Sample answer original price $100 final price
$050
b Sample answer original price $100 final price
$9950
c Sample answer original price $100 final price
$350
16 p = 127 ( $7400 ) = $9398
s = 127 ( $4800 ) = $6096
j = 127 ( $32500 ) = $41275
2 ( 9398 ) + 3 ( $6096 ) + $41275 = $78359
17 Either buy 3 get one free or 1 __ 4 off Either case would
result in a discount of 25 which is better than 20
Focus on Higher Order Thinking
18 No she is taking a loss Her cost for the tea is t so
the retail price is 12t The discounted price is
08 ( 12t ) or 096t which is less than t
19 No first change 201 decrease second change
251 increase The second percent change is
greater
20 Rafael can purchase the coat after 11 or 12 weeks
after 11 weeks the price is $10932 after 12 weeks
the price is $10385 and after that Danielle donates
the coat
LESSON 53
Your Turn
1 005 times $2000 = $100 $100 + $2000 = $2100
3 005 times $40000 = $2000
$2000 times 4 years = $8000
$40000 + $8000 = $48000
4 Commission $4500 times 00375 = $16875
Total $2200 + $16875 = $236875
Guided Practice
1 005 times $3000 = $150
2 015 times $7000 = $1050
3 0004 times $10000 = $040
4 15 times $2200 = $3300
5 001 times $8000 = $080
6 20 times $500 = $1000
7 a 007 times $4399 = $308
b $4399 + $308 = $4707
8 115 times $7550 = $8683
9 007 times $2000 = $140
$140 times 5 years = $700
10 003 times $550 = $1650
$1650 times 10 years = $165
$550 + $165 = $715
11 a 090 times $20 = $18
b 1085 times $18 = $1953
12 020 times $2999 = $600 tip
00625 times $2999 = $187 tax
$2999 + $600 + $187 = $3786 total
13 Write the tax rate as a decimal Then multiply the
decimal by the price of the item and add the result
to the price
Independent Practice
14 $3275 + $3988 = $7263 total meal cost
014 times $7263 = $1017 tip
$7263 + $1017 = $8280 total with tip
15 $7865 times 015 = $1180 meal discount
$7865 times 020 = $1573 tip
$7865 + $1573 - $1180 = $8258 total
16 $125 times 235 = $29375 retail ring cost
0075 times $29375 = $2203 tax
$29375 + $2203 = $31578 total with tax
Copyright copy by Houghton Mifflin Harcourt 30 All rights reserved
17 $7999 times 012 = $960 discount
$7999 - $960 = $7039 price before tax
$7039 times 10675 = $7514 total with tax
18 4 times $999 times 020 = $799 discount
4 times $999 - $799 = $3197 price before tax
$3197 times 10675 = $3413 total with tax
19 $4500 + 00725 = $32625 commission
$750 + $32625 = $107625 total income
20 $700 times 0055 = $3850 commission
$475 + $3850 = $51350 total income
21 a Multiply Sandrarsquos height by 010 and add the
product to 4 to get Pablorsquos height Then multiply
Pablorsquos height by 008 and add the product to
Pablorsquos height to get Michaelarsquos height
b Using 48 inches for 4 feet
48 inches times 01 = 48 inches so Pablorsquos height is
53 inches or 4 feet 5 inches to the nearest inch
53 inches times 008 = 42 inches so Michaelarsquos
height is 57 inches or 4 feet 9 inches to the
nearest inch
22 a $4998 times 05 = $2499 50 discount
$2499 - $1000 = $1499 $10 discount
b $4998 - $1000 = $3998 $10 discount
$3998 times 05 = $1999 50 discount
23 a $95 times 09 = $8550 discounted camera
$8550 + $1599 = $10149 total
b $1599 times 09 = $1439 discounted battery
$95 + $1439 = $10939 total
c Eric should apply the discount to the digital
camera he can save $8
d $10149 times 008 = $812 tax
$10149 + $812 = $10961 total
24 a Store 1 $22 divide 2 = $11
Store 2 $1299 times 09 = $1169
Store 1 charges $11 per shirt and Store 2
charges $1169 Therefore I would save
$069 per shirt at Store 1
b Store 3 $2098 times 045 = $944
Yes It is selling shirts at $944
Focus on Higher Order Thinking
25 Marcus should choose the option that pays $2400
plus 3 of sales He would make $2550 to $2700
per month The other option would pay only $1775
to $2050 per month
26 Percent error = ǀ 132 - 137 ǀ
____________ 137
times 100 = 05 ____ 137
asymp 36
MODULE 5
Ready to Go On
1 x = ( 63 - 36 )
_________ 36
x = 27 ___ 36
= 75 increase
2 x = ( 50 - 35 )
_________ 50
x = 15 ___ 50
= 30 decrease
3 x = ( 72 - 40 )
_________ 40
x = 32 ___ 40
= 80 increase
4 x = ( 92 - 69 )
_________ 92
x = 23 ___ 92
= 25 decrease
5 $60 times 015 = $9
$60 + $9 = $69
6 $32 times 0125 = $4
$32 + $4 = $36
7 $50 times 022 = $11
$50 - $11 = $39
8 $125 times 030 = $3750
$12500 - $3750 = $8750
9 $4800 times 0065 = $312 commission
$325 + $312 = $637 total income
10 $5310
______ $1735
asymp 31
11 Find the amount per hour that Priya makes if she
makes 20 more than James
$700 times 020 = $140
$700 + $140 = $840
Next find the amount Slobhan makes if he makes
5 less than Priya
$840 times 005 = $042
$840 - $042 = $798
Slobhan makes $798 per hour
12 Both the 6 tax and the 20 tip are applied to the
initial cost of the meal so the two percents can be
added together and multiplied by the cost
$45 times 026 = $1170
$45 + $1170 = $5670
The total cost of the meal is $5670
13 Sample answer sales tax increase discount
decrease tip increase
Copyright copy by Houghton Mifflin Harcourt 31 All rights reserved
MODULE 6 Expressions and Equations
Are You Ready
1 5 + x
2 11 - n
3 -9 ___ y
4 2x - 13
5 2x + 3
= 2 ( 3 ) + 3
= 6 + 3
= 9
6 -4x + 7
= -4 ( 1 ) + 7
= -4 + 7
= 11
7 15x - 25
= 15 ( 3 ) - 25
= 45 - 25
= 2
8 04x + 61
= 04 ( -5 ) + 61
= -20 + 61
= 41
9 2 __ 3 x - 12
= 2 __ 3
( 18 ) - 12
= 2 __ 3
times ( 18 ___ 1 ) - 12
= 36 ___ 3 - 12
= 0
10 - 5 __ 8
x + 10
= - 5 __ 8 ( -8 ) + 10
= - 5 __ 8 times- 8 __
1 + 10
= - 5 ___ 1 8
times- 8 1 __
1 + 10
= - 5 __ 1 times- 1 __
1 + 10
= 5 + 10
= 15
11 1 __ 2 divide 1 __
4
= 1 times 4 _____ 2 times 1
= 1 times 4 2 ______
1 2 times 1
= 1 times 2 _____ 1 times 1
= 2
12 3 __ 8 divide 13 ___
16
= 3 __ 8 times 16 ___
13
= 3 times 16 2 _______
1 8 times 13
= 3 times 2 ______ 1 times 13
= 6 ___ 13
13 2 __ 5 divide 14 ___
15
= 2 __ 5 times 15 ___
14
= 1 2 times 15
3 ________
1 5 times 14 7
= 1 times 3 _____ 1 times 7
= 3 __ 7
14 4 __ 9 divide 16 ___
27
= 4 __ 9 times 27 ___
16
= 1 4 times 27
3 ________
1 9 times 16 4
= 1 times 3 _____ 1 times 4
= 3 __ 4
LESSON 61
Your Turn
2 ( 3x + 1 __ 2 ) + ( 7x - 4 1 __
2 )
= 3x + 7x + 1 __ 2 - 4 1 __
2
= 10x - 4
3 ( -025x - 3 ) - ( 15x + 14 ) = -025x - 3 - 15x - 14
= -175x - 44
4 02(3b - 15c) + 6c
= 06b - 3c + 6c
= 06b + 3c
5 2 __ 3 (6e + 9f - 21g) - 7f
= 4e + 6f - 14g - 7f
= 4e - f - 14g
6 5x - 3(x - 2) - x
= 5x - 3x + 6 - x
= x + 6
7 83 + 34y - 05(12y - 7)
= 83 + 34y - 6y + 35
= 118 - 26y
Solutions KeyExpressions Equations and Inequalities
UNIT
3
Copyright copy by Houghton Mifflin Harcourt 32 All rights reserved
Guided Practice
1 baseballs 14 + (12)n tennis balls 23 + (16)n
14 + 12n + 23 + 16n
14 + 23 + 12n + 16n
37 + 28n
So the total number of baseballs and tennis balls is
37 + 28n
2 37 + 28n
37 + 28 ( 9 )
= 37 + 252
= 289
3 14 + 5(x + 3) - 7x = 14 + 5x + 15 - 7x
= 29 - 2x
4 3 ( t - 4 ) - 8 ( 2 - 3t ) = 3t - 12 - 16 + 24t
= 27t - 28
5 63c - 2 ( 15c + 41 ) = 63c - 3c - 82
= 33c - 82
6 9 + 1 __ 2 ( 7n - 26 ) - 8n = 9 + 35n - 13 - 8n
= -4 - 4 1 __ 2 n
7 2x + 12
2 ( x + 6 )
8 12x + 24
12 ( x + 2 )
9 7x + 35
7 ( x + 5 )
10 You multiply numbers or expressions to produce a
product You factor a product into the numbers or
expressions that were multiplied to produce it
Independent Practice
11 Let d = number of days
Fee for 15 food booths 15 ( 100 + 5d ) Fee for 20 game booths fee 20 ( 50 + 7d ) Amount the company is paid for the booths
15 ( 100 + 5d ) + 20 ( 50 + 7d ) = 15 ( 100 ) + 15 ( 5d ) + 20 ( 50 ) + 20 ( 7d )
= 1500 + 75d + 1000 + 140d
= 1500 + 1000 + 75d + 140d
= 2500 + 215d
12 New length 96 + l
New width 60 + w
Perimeter of new pattern
2(96 + l) + 2(60 + w)
=2(96) + 2l + 2(60) + 2w
192 + 2l + 120 + 2w
192 + 120 + 2l + 2w
312 + 2l + 2w
13 Width 3
Length 1 x-tile and 2 +1-tiles
Factors 3 and x + 2
Product 3 ( x + 2 ) = 3x + 6
14 Width 4
Length 2 x-tiles and 1 -1-tile
Factors 4 and 2x - 1
Product 4 ( 2x - 1 ) = 8x - 4
15 The area is the product of the length and width
( 6 times 9 ) It is also the sum of the areas of the
rectangles separated by the dashed line ( 6 times 5
and 6 times 4 ) So 6 ( 9 ) = 6 ( 5 ) + 6 ( 4 )
16 Perimeter of triangle ( x + 3 ) + ( 2x + 4 ) +
6x = ( x + 3 ) + ( 2x + 4 ) +
6x = 3x + 7 +
-3x = _ -3x
3x = 7 +
_ -7 = _ -7
3x - 7 =
The length of the side is 3x - 7
17 Perimeter of rectangle 2 ( 3x - 3 ) + 2 ( )
10x + 6 = 2 ( 3x - 3 ) + 2 ( )
10x + 6 = 6x - 6 + 2
_ -6x = _ -6x
4x + 6 = - 6 + 2
_ + 6 = _ + 6
4x + 12 = 2
( 4x + 12 ) divide 2 = ( 2 ) divide 2
2x + 6 =
The length of the side is 2x + 6
18 a P = 2l + 2w
Perimeter of tennis court T
2(2x + 6) + 2(x)
= 4x + 12 + 2x
= 6x + 12
Perimeter of basketball court B
2(3x - 14) + 2( 1 __ 2 x + 32)
= 6x - 28 + x + 64
= 7x + 36
b (7x + 36) - (6x + 12)
= 7x + 36 - 6x - 12
= x + 24
c Find the length of tennis court
Let x = 36
2x + 6 = 2 ( 36 ) + 6
= 72 + 6
= 78
Find the width of the basketball court
Let x = 36
1 __ 2 x + 32 = 1 __
2 ( 36 ) + 32
= 18 + 32
= 50
Find the length of the basketball court
Let x = 36
3x - 14 = 3 ( 36 ) - 14
= 108 - 14
= 94
The tennis court is 36 ft by 78 ft The basketball
court is 50 ft by 94 ft
Focus on Higher Order Thinking
19 Find the area of each small square and rectangle
( x ) ( x ) = x 2
( x ) 1 = x
( 1 ) 1 = 1
Copyright copy by Houghton Mifflin Harcourt 33 All rights reserved
x
x
1
11
1 1
x2 x x x
x 1 1 1x 1 1 1
Area =
x 2 + x + x + x + x + x + 1 + 1 + 1 + 1 + 1 + 1
= x 2 + 5x + 6
( x + 3 ) ( x + 2 ) = x 2 + 5x + 6
20 Agree To find 58 times 23 let 23 = 3 + 20 Then find
the product 58 ( 3 + 20 ) First step 58 ( 3 ) = 174
Second step 58 ( 20 ) = 1160 Third step 174 +
1160 = 1334 So 58 ( 23 ) = 58 ( 3 ) + 58 ( 20 )
21 ( 1 ) Think of 997 as 1000 - 3 So 8 times 997 = 8 ( 1000 - 3 ) By the Distributive Property
8 ( 1000 - 3 ) = 8000 - 24 = 7976
( 2 ) Think of 997 as 900 + 90 + 7 By the Distributive
Property 8 ( 900 + 90 + 7 ) = 7200 + 720 + 56 =
7976
LESSON 62
Your Turn
1 49 + z = -9
_ -49 _ -49
z = -139
2 r - 171 = -48
_ +171 _ +171
r = 123
3 -3c = 36
-3c ____ -3
= 36 ___ -3
c = -12
5 x - 15 = 525
_ +15 _ +15
x = 675
The initial elevation of the plane is 675 miles
6 x ___ 35
= -12
x ___ 35
( 35 ) = -12 ( 35 )
x = -42
The decrease in the value of the stock was $420
7 25x = 75
25x ____ 25
= 75 ___ 25
x = 3
The power was restored in 3 hours
Guided Practice
1 Let x represent the number of degrees warmer the
average temperature is in Nov than in Jan
x + ( -134 ) = -17 or x - 134 = -17
x - 134 = -17
_ +134 _ +134
x = 117
The average temperature in November is 117degF
warmer
2 Let x represent the number of days it takes the
average temperature to decrease by 9degF
-1 1 __ 2 x = -9
( - 2 __ 3 ) ( - 3 __
2 x ) = ( - 2 __
3 ) ( -9 )
x = 18 ___ 3
x = 6
It took 6 days for the temperature to decrease by 9degF
3 -2x = 34
-2x ____ -2
= 34 ___ -2
x = -17
4 y - 35 = -21
_ + 35 _ + 35
y = 14
y = 14
5 2 __ 3 z = -6
( 3 __ 2 ) 2z ___
3 = ( 3 __
2 ) ( -6 )
z = -9
6 Sample answer It helps me describe the problem
precisely and solve it using inverse operations
Independent Practice
7 Let x equal the elevation of Mt Everest
x - 870737 = 203215
_ +870737 _ +870 737
x = 2902887
The elevation of Mt Everest is 2902887 ft
8 Let x equal the number of feet Liam descended
2825131 - x = 2320106
_ -2825131 _ -2825131
-x = - 505025
x = 505025
Liam descended 505025 ft
His change in elevation was -505025 ft
9 Let x equal the elevation of Mt Kenya
2825131 - x = 1119421
_ -2825131 _ -2825131
-x = -1705710
x = 1705710
The elevation of Mt Kenya is 170571 ft
10 Find the change in elevation
1250 - 935 = 315
Use an equation
Let x = the number of minutes the balloon
descends
( -22 1 __ 2 ) x = -315
( - 45 ___ 2 ) x = -315
( - 2 ___ 45
) ( - 45 ___ 2 ) x = -315 ( - 2 ___
45 )
x = 14
It will take the balloon 14 minutes to descend
11 Find the change in elevation
4106 - 3205 = 901
Use an equation to find the rate of descent
Copyright copy by Houghton Mifflin Harcourt 34 All rights reserved
Let x = rate of descent
34x = 901
34x ____ 34
= 901 ____ 34
x = 265 = 26 1 __ 2
The rate of descent was 26 1 __ 2 feet per minute
12 Let x = the number of degrees warmer Montanarsquos
average temperature is than Minnesotarsquos
- 25 + x = -07
_ + 25 _ + 25
x = 18
Montanarsquos average 3-month temperature is 18degC
warmer than Minnesotarsquos
13 Let x = the number of degrees warmer Floridarsquos
average temperature is than Montanarsquos
181 - x = -07
_ - 181 _ -181
-x = -188
x = 188
Floridarsquos average 3-month temperature is 188degC
warmer than Montanarsquos
14 Let x = the number of degrees the average
temperature in Texas would have to change
125 + x = 181
_ -125 _ -125
x = 56
It would have to increase by 56degC
15 Let x = the number of yards the team must get on
their next play
-26 1 __ 3
+ x = 10
+26 1 __ 3
______
+26 1 __ 3
______
x = 36 1 __ 3
The team needs to get 36 1 __ 3 yards on their next play
16 Let x = the number of seconds
( -2 1 __ 2 ) x = -156
( -25 ) x = -156
( -25 _____ -25
) x = -156 ______ -25
x = 624
It takes the diver 624 seconds to reach -156 feet
17 Sample answer The elevation is the product of the
rate and the time
18 Let x = the total amount withdrawn
x __ 5 = 455
( 5 ) x __ 5 = 455 ( 5 )
x = 2275
The total amount she withdrew was $22750
Sample answer
$4550 asymp $50 and $50 times 5 = $250 which is close
to $22750
Focus on Higher Order Thinking
19 ( 1 ) The elevations of the diver and the reef both are
below sea level
( 2 ) The change in the planersquos elevation the plane
descends the plane is moving from a higher to a
lower elevation
20 -4x = -48
( -4x ____ -4
) = -48 _____ -4
x = 12
- 1 __ 4 x = -48
( -4 ) ( - 1 __ 4 ) x = -48 ( -4 )
x = 192
192 ____ 12
= 16
In the first case -4x = -48 you divide both sides
by -4 In the second - 1 __ 4 x = -48 you multiply
both sides by -4 The second solution (192) is
16 times the first (12)
21 Add the deposits and the withdrawals Let x repre-
sent the amount of the initial deposit Write and
solve the equation x + deposits - withdrawals =
$21085
LESSON 63
Your Turn
4 Let x represent the number of video games Billy
purchased
Original balance on gift card $150
Cost for x video games $35 middot x
Final balance on gift card $45
Original balance minus $35 times number of games equals $45
darr darr darr darr darr darr darr $150 - $35 middot x = $45
Equation 150 - 35x = 45
5 Sample answer You order x pounds of coffee from
Guatemala at $10 per pound and it costs $40 to
ship the order How many pounds can you order so
that the total cost is $100
Guided Practice
1
+ + ++ ++
+++ + +
+++
2
----
+ ++ ++
- - -
Copyright copy by Houghton Mifflin Harcourt 35 All rights reserved
3 Let a represent the number of adults that attend
Ticket cost for 1 child = $6
Ticket cost for a adults = $9 middot a
Total cost for movie = $78
cost for child plus $9 times number of adults equals $78
darr darr darr darr darr darr darr $6 + $9 middot a = $78
Equation 6 + 9a = 78
4 x is the solution of the problem
2x is the quantity you are looking for multiplied by 2
+ 10 means 10 is added to 2x
= 16 means the result is 16
5 Sample answer A department store is having a sale
on recliners buy two and get a discount of $125
Sanjay purchases two recliners and the total cost
(before taxes) is $400 What is the price of a single
recliner not including any discounts
6 Choose a variable to represent what you want to
find Decide how the items of information in the
problem relate to the variable and to each other
Then write an equation tying this all together
Independent Practice
7 On one side of a line place three negative variable
tiles and seven +1-tiles and then on the other side
place 28 +1-tiles
8 Let d represent the number of days Val rented the
bicycle
Flat rental fee $5500
Cost for d days of rental $850 middot dTotal cost $123
$850 times number of days plus flat fee equals total cost
darr darr darr darr darr darr darr $850 bull d + $55 = $123
Equation 85d + 55 = 123
9 Let r represent the number of refills
Refill mug cost $675
Cost for r refills $125 middot r Total cost $3175
$125 times number of refills plus refill mug cost equals total cost
darr darr darr darr darr darr darr $125 bull r + $675 = $3175
Equation 125r + 675 = 3175
10 Let n represent the number of weekday classes
The Saturday class lasts 60 minutes
The length of time for the weekday classes is 45 middot n
The total number of minutes for all classes in a week
is 28545 minutes times number of plus minutes for equals total minutes
weekday classes Saturday class
darr darr darr darr darr darr darr45 bull n + 60 = 285
Equation 45n + 60 = 285
11 Let n represent the number of African animals
Half the number of African animals is 1 __ 2 n
45 more than the number of African animals
means + 45
The total number of animals is 172
half times number of and 45 more than number equals total number
African animals of African animals of animals
darr darr darr darr darr darr
1 _ 2
bull n + 45 = 172
Equation 1 __ 2 n + 45 = 172
12 Let u represent the number of uniforms
Cost for basketball equipment $548
Cost for u uniforms $2950 middot uTotal cost $2023
$2950 times number of plus cost for basketball equals total cost
uniforms equipment
darr darr darr darr darr darr darr $2950 bull u + $548 = $2023
Equation 295u + 548 = 2023
13 Let x represent the number of weeks
Initial amount in account $500
$20 per week 20 middot xFinal amount in account $220
initial amount minus 20 times number of equals final amount
weeks
darr darr darr darr darr darr darr 500 - 20 bull x = 220
Equation 500 - 20x = 220
14 a The equation adds 25 but Deenarsquos scenario
involves subtracting 25
b Let x represent the number of shirts
Cost of shirts before discount 9 middot xDiscount means subtract
Amount of discount $25
Total bill $88
9 times number of minus discount equals total
shirts bill
darr darr darr darr darr darr darr 9 bull x - 25 = 88
Equation 9x - 25 = 88
c Sample answer I bought some shirts at the store
for $9 each and a pair of jeans for $25 making
my bill a total of $88 How many shirts did I buy
15 a Let c represent the number of children
Flat fee for Sandy $10
Cost per child for Sandy $5 middot cTotal charge for Sandy $10 + $5c
Total charge for Kimmi $25
To compare the two costs set these values equal
Equation 10 + 5c = 25
b Solve the equation to find c the number of
children a family must have for Sandy and Kimmi
to charge the same amount
10 + 5c = 25
10 - 10 + 5c = 25 - 10
5c = 15
5c ___ 5 = 15 ___
5
c = 3
3 children
c They should choose Kimmi because she charges
only $25 If they chose Sandy they would pay
10 + 5 ( 5 ) = $35
Copyright copy by Houghton Mifflin Harcourt 36 All rights reserved
Focus on Higher Order Thinking
16 To get Andresrsquo equation you can multiply every
number in Peterrsquos equation by 4 To get Peterrsquos
equation you can divide every number in Andrewrsquos
equation by 4 or multiply by 1 __ 4
17 Part of the equation is written in cents and part in
dollars All of the numbers in the equation should be
written either in cents or dollars
18 Sample answer Cici has a gift card with a balance
of 60 She buys several T-shirts for $8 each Her new
balance is $28 after the purchases Write an
equation to help find out how many T-shirts Cici
bought
LESSON 64
Your Turn
1 Model the equation
+ ++ +
+ ++ ++ +
+ ++ ++ +
++
Remove 5 +1-tiles from each side of the mat
+ ++ +
+ ++ ++ +
+ ++ ++ +
++
Divide each side into two equal groups
++
+ ++ +
++
The solution is x = 3
++ ++
2 Model the equation
+ + ++ + ++ +
+++
+++
__
Add 1 +1-tile to each side of the mat Note that
a negative-positive tile pair results in zero
+ + ++ + ++
++ +
+++
+++
__
Divide each side into two equal groups
+ + ++++ + +++
The solution is n = 3
+ + +++
3 Model the equation
++++
______
______
____
Add 3 +1-tiles to each side of the mat Note that
a negative-positive tile pair results in zero
++++
+
++
+
++
______
______
____
Divide each side into two equal groups
++++
____
The solution is a = -1
++ __
Copyright copy by Houghton Mifflin Harcourt 37 All rights reserved
4 Model the equation
____
________
++
Add 2 -1-tiles to each side of the mat Note that
a negative-positive tile pair results in zero
________
________
++
____
Divide each side into two equal groups
________
________
We get -y = -1
____
In order to change -y to y add a positive y-variable
tile to each side
++
__ ++ __
Add 1 +1-tile to each side of the mat
++++
__
The solution is y = 1
+++
6 3n + 10 = 37
Solve the equation for n
3n + 10 = 37
-10 ____
-10 ____
3n = 27
3n ___ 3 = 27 ___
3
n = 9
The triplets are 9 years old
7 n __ 4 - 5 = 15
Solve the equation for n
n __ 4 - 5 = 15
+5 ___
+5 ___
n __ 4 = 20
n __ 4 ( 4 ) = 20 ( 4 )
n = 80
The number is 80
8 -20 = 5 __ 9 ( x - 32 )
Solve the equation for x
-20 = 5 __ 9 ( x - 32 )
-20 = 5 __ 9 x - 160 ____
9
+ 160 ____ 9
______
+ 160 ____ 9
______
- 20 ___ 9 = 5 __
9 x
- 20 ___ 9 divide ( 5 __
9 ) = 5 __
9 x divide ( 5 __
9 )
4 20 times 9
1 _______
9 1 times 5
1 = x
- 4 __ 1 = x
-4 = x
The temperature in the freezer is -4degF
9 120 - 4x = 92
Solve the equation for x
120 - 4x = 92
-120 _____
-120 _____
- 4x = -28
-4x ____ -4
= -28 ____ -4
x = 7
She had 7 incorrect answers
Copyright copy by Houghton Mifflin Harcourt 38 All rights reserved
Guided Practice
1 To solve the equation with algebra tiles first remove
one +1-tile from both sides Then divide each side
into two equal groups
2 Remove 1 +1-tile from each side
++++
+ +++++++++
Divide each side into two equal groups
++++
++++++++
The solution is x = 4
++ + + + +
3 Let w = the width of the frame
2 times height plus 2 times width equals perimeter
darr darr darr darr darr darr darr darr darr2 bull 18 + 2 bull w = 58
Solve the equation
2 ( 18 ) + 2w = 58
36 + 2w = 58
36 - 36 + 2w = 58 - 36
2w = 22
2w ___ 2 = 22 ___
2
w = 11
The width is 11 inches
4 1200 minus 25x = 500
Solve the equation for x
1200 - 25x = 500
_ -1200 _ -1200
-25x = -700
-25x _____ -25
= -700 _____ -25
x = 28
The manager will reorder in 28 days
5 Use the inverse operations of the operations
indicated in the problem If the equation does
not involve parentheses use addition or subtraction
before multiplication or division to solve the
equation
Independent Practice
6 9s + 3 = 57
9s + 3 - 3 = 57 - 3
9s = 54
9s ___ 9 = 54 ___
9
s = 6
7 4d + 6 = 42
4d + 6 - 6 = 42 - 6
4d = 36
4d ___ 4 = 36 ___
4
d = 9
8 115 - 3y = -485
115 - 115 - 3y = -485 - 115
thinsp-3y = -60
-3y
____ -3
= -60 ____ -3
y = 20
9 k __ 2 + 9 = 30
k __ 2 + 9 - 9 = 30 - 9
k __ 2 = 21
2 sdot k __ 2 = 2 sdot 21
k = 42
10 g
__ 3 - 7 = 15
g
__ 3 - 7 + 7 = 15 + 7
g
__ 3 = 22
3 sdot g
__ 3 = 3 sdot 22
g = 66
11 z __ 5 + 3 = -35
z __ 5 + 3 - 3 = -35 - 3
z __ 5 = -38
5 sdot z __ 5 = 5 ( -38 )
z = -190
12 -9h - 15 = 93
-9h - 15 + 15 = 93 + 15
-9h = 108
-9h ____ -9 = 108 ____
-9
h = -12
13 - 1 __ 3 (n + 15) = -2
- 1 __ 3 n - 5 = -2
- 1 __ 3 n - 5 + 5 = -2 + 5
- 1 __ 3 n = 3
-3 sdot - 1 __ 3 n = -3 sdot 3
n = -9
14 -17 + b __ 8 = 13
-17 + 17 + b __ 8 = 13 + 17
b __ 8 = 30
8 sdot b __ 8 = 8 sdot 30
b = 240
Copyright copy by Houghton Mifflin Harcourt 39 All rights reserved
15 7 ( c - 12 ) = -21
7c - 84 = -21
_ +84 _ +84
7c = 63
7c ___ 7 = 63 ___
7
c = 9
16 -35 + p
__ 7 = -52
-35 + 35 + p
__ 7 = -52 + 35
p
__ 7 = -17
7 sdot p
__ 7 = -17 sdot 7
p = -119
17 46 = -6t - 8
46 + 8 = -6t - 8 + 8
54 = -6t
54 ___ -6
= -6t ____ -6
t = -9
18 Let a = the original amount in the account
Double the (original plus 26) equals new
sum of amount amount
darr darr darr darr darr darr
2 (a + $26) = $264
Solve the equation
2 ( a + 26 ) = 264
2 ( a + 26 )
_________ 2 = 264 ____
2
a + 26 = 132
a + 26 - 26 = 132 - 26
a = 106
Puja originally had $106 in the account
19 Let t = the temperature 6 hours ago
Twice temperature less 6 degrees equals current
6 hours ago temperature
darr darr darr darr darr darr 2middot t - 6 = 20
Solve the equation
2t - 6 = 20
2t - 6 + 6 = 20 + 6
2t = 26
2t __ 2 = 26 ___
2
t = 13
Six hours ago it was 13 degF in Smalltown
20 -35 = 5 __ 9 ( x - 32 )
-35 = 5 __ 9 x - 160 ____
9
+ 160 ____ 9
______
+ 160 ____ 9
- 155 ____ 9 = 5 __
9 x
thinsp- 155 ____ 9 divide ( 5 __
9 ) = 5 __
9 x divide ( 5 __
9 )
-thinsp 31
155 times 9
1
= x
9 1
times 5
1
- 31 ___ 1 = x
-31 = x
The temperature is -31degF
21 Let a = Artaudrsquos ageopposite of Artaudrsquos age add 40 equals 28
darr darr darr darr darr darr(-) a + 40 = 28
Solve the equation
-a + 40 = 28
-a + 40 - 40 = 28 - 40
-a = -12
-a ___ -1
= -12 ____ -1
a = 12
Artaud is 12 years old
22 Let c = number of customers when Sven startedtwice number of
customers when Sven started
plus 11 more equals present number of customers
darr darr darr darr darr2 middot c +11 = 73
Solve the equation
2c + 11 = 73
2c + 11 - 11 = 73 - 11
2c = 62
2c ___ 2 = 62 ___
2
c = 31
Sven had 31 customers when he started
23 Let p = original price of the jacket
half original less $6 equals amount
price paid
darr darr darr darr darr
1 __ 2
middot p -6 = 88
Solve the equation
1 __ 2 p - 6 = 88
1 __ 2 p - 6 + 6 = 88 + 6
1 __ 2 p = 94
2 sdot 1 __ 2 p = 2 sdot 94
p = 188
The original price was $188
Copyright copy by Houghton Mifflin Harcourt 40 All rights reserved
24 115 minus 8n = 19
Solve the equation for n
115 - 8n = 19
_ -115 _ -115
-8n = -96
-8n _____ -8
= -96 _____ -8
n = 12
They had 19 apples left after 12 days
25 -55x + 056 = -164
-55x + 056 - 056 = -164 - 056
-55x = -22
-55x ______ -22
= -22 _____ -22
x = 04
26 -42x + 315 = -651
-42x + 315 - 315 = -651 - 315
-42x = -966
-42x ______ -42
= -966 ______ -42
x = 23
27 k ___ 52
+ 819 = 472
k ___ 52
+ 819 - 819 = 472 - 819
k ___ 52
= -347
52 sdot k ___ 52
= 52 ( -347 )
k = -18044
28 Sample answer -3x - 5 = -26
29 Sample answer x __ 5 + 10 = 5
30 When dividing both sides by 3 the student forgot to
divide 2 by 3
3x + 2 = 15
3x ___ 3 + 2 __
3 = 15 ___
3
x + 2 __ 3 = 5
- 2 __ 3
___
- 2 __ 3
___
x = 5 - 2 __ 3
x = 5 times3
___ 1
times3 - 2 __
3
x = 15 ___ 3 - 2 __
3
x = 13 ___ 3 or 4 1 __
3
The solution should be x = 4 1 __ 3
31 a 2(x + 40) = 234
Solve the equation for x
2x + 80 = 234
2x + 80 - 80 = 234 - 80
2x = 154
2x ___ 2 = 154 ____
2
x = 77
Trey saved $77
b Sample answer In both solutions you would
divide $234 by 2 then subtract 40 234 divide 2 ndash 40
= 77 These are the same operations applied in
the same order as when solving the equation
Focus on Higher Order Thinking
32 F = 18c + 32
F - 32 = 18c + 32 - 32
F - 32 = 18c
F - 32 ______ 18
= 18c ____ 18
F - 32 ______ 18
= c
33 P = 2 ( ℓ + w ) P = 2ℓ + 2w
P - 2ℓ = 2ℓ - 2ℓ + 2w
P - 2ℓ = 2w
P - 2ℓ ______ 2 = 2w ___
2
P - 2ℓ ______ 2 = w
34 ax + b = c
ax + b - b = c - b
ax = c - b
ax ___ a = c - b ______ a
x = c - b ______ a
MODULE 6
Ready to Go On
1 Add the amounts for the cost of first day of the field
trip with the second day of the field trip where n is
the number of members in the club
15n + 60 + 12n + 95
Therefore the total cost of the two-day field trip can
be written as the expression 27n + 155
2 h + 97 = -97
_ -97 _ -97
h = -194
3 - 3 __ 4 + p = 1 __
2
+ 3 __ 4 + 3 __
4
p = 1 __ 2 + 3 __
4
p = 1 times2
___ 2
times2 + 3 __
4
p = 2 __ 4 + 3 __
4
p = 5 __ 4
4 -15 = -02k
-15 _____ -02
= -02k ______ -02
75 = k
Copyright copy by Houghton Mifflin Harcourt 41 All rights reserved
5 y ___
-3 = 1 __
6
y ___
-3 ( -3 ) = 1 __
6 ( -3 )
y = 1 __ 6 times -3 ___
1
y = -3 ___ 6
y = -1 ___ 2
6 - 2 __ 3
m = -12
- 2 __
3 m _____
- 2 __ 3 = -12 ____
- 2 __ 3
m = -12 divide - 2 __ 3
m = -12 ____ 1 divide - 2 __
3
m = -12 ____ 1 times - 3 __
2
m = -36 ____ -2
m = 18
7 24 = - t ___ 45
24 ( 45 ) = - t ___ 45
( 45 )
108 = -t
-108 = t
8 Let d represent the number of the day after the first
day for example d = 1 means the first day after the
day he started number of number number
2 times day after plus of sit-ups equals of sit-ups
first day first day today
darr darr darr darr darr darr darr
2 middot d + 15 = 33
Equation 2d + 15 = 33
9 5n + 8 = 43
5n + 8 - 8 = 43 - 8
5n = 35
5n ___ 5 = 35 ___
5
n = 7
10 y __
6 - 7 = 4
y __
6 - 7 + 7 = 4 + 7
y __
6 = 11
6 sdot y __
6 = 6 sdot 11
y = 66
11 8w - 15 = 57
8w - 15 + 15 = 57 + 15
8w = 72
8w ___ 8 = 72 ___
8
w = 9
12 g
__ 3 + 11 = 25
g
__ 3 + 11 - 11 = 25 - 11
g
__ 3 = 14
3 sdot g
__ 3 = 3 sdot 14
g = 42
13 f __ 5 - 22 = -25
f __ 5 - 22 + 22 = -25 + 22
f __ 5 = -03
5 sdot f __ 5 = 5 ( -03 )
f = -15
14 - 1 __ 4 (p + 16) = 2
- 1 __ 4 p - 4 = 2
- 1 __ 4 p - 4 + 4 = 2 + 4
- 1 __ 4 p = 6
-4 sdot - 1 __ 4 p = 6 sdot -4
p = -24
15 Sample answer Analyze the situation to determine
how to model it using a two-step equation Solve
the equation Interpret the solution in the given
situation
Copyright copy by Houghton Mifflin Harcourt 42 All rights reserved
MODULE 7 Inequalities
Are You Ready
1 9w = -54
9w ___ 9 = -54 ____
9
w = -6
2 b - 12 = 3
thinsp _ + 12 = _ + 12
b = 15
3 n __ 4
= -11
4 times n __ 4
= 4 ( -11 )
n = -44
4-7
ndash5ndash10 0 5 10
75 4 6
8 3 - (-5)
3 + 5
8
9 -4 - 5
-9
10 6 - 10
-4
11 -5 - (-3)
-5 + 3
-2
12 8 - (-8)
8 + 8
16
13 9 - 5
4
14 -3 - 9
-12
15 0 - (-6)
0 + 6
6
LESSON 71
Your Turn
4 y minus 5 ge minus7
_ +5 _ +5
y ge minus2
-4-5 -3 -2-1 0 1 2 3 4 5
Check Substitute 0 for y
minus1 ge -8
minus1(minus2) le -8(minus2)
2 le 16
5 21 gt 12 + x
_ -12 _ minus12
9 gt x
x lt 9
10 2 3 4 5 6 7 8 9 10
Check Substitute 8 for x
21 gt 12 + 8
21 gt 12 + 8
21 gt 20
6 -10y lt 60
-10y
_____ -10
lt 60 ____ -10
y gt -6
-10-9 -8 -7 -6 -5 -4 -3 -2-1 0 1
Check Substitute -5 for y
-10y lt 60
-10(-5) lt 60
50 lt 60
7 7 ge - t __ 6
7(-6) le - t __ 6 (-6)
-42 le t
t ge -42
-46 -45 -44 -43 -42 -41 -40-47
Check Substitute -36 for t
7 ge - t __ 6
7 ge - ( -36 ____
6 )
7 ge 6
8 Write and solve an inequality
Let m = the number of months
35m le 315
35m ____ 35
le 315 ____ 35
m le 9
Tony can pay for no more than 9 months of his gym
membership using this account
Guided Practice
1 -5 le -2
_ +7 _ +7
2 le 5
2 -6 lt -3
-6 ___ -3
gt -3 ___ -3
2 gt 1
3 7 gt -4
_ -7 _ -7
0 gtthinsp -11
Copyright copy by Houghton Mifflin Harcourt 43 All rights reserved
4 -1 ge -8
-1 ( -2 ) le -8 ( -2 )
2 le 16
5 n - 5 ge -2
_ +5 _ +5
n ge 3
-5 -4 -3 -2-1 0 3 4 51 2
Check Substitute 4 for n
n - 5 ge -2
4 - 5 ge -2
-1 ge -2
6 3 + x lt 7
_ -3 _ -3
x lt 4
-2-1 0 3 4 5 6 7 81 2
Check Substitute 3 for x
3 + x lt 7
3 + 3 lt 7
6 lt 7
7 -7y le 14
-7y
____ -7 ge 14 ___ -7
y ge -2
-5-6-7 -4 -3 -2-1 0 1 2 3
Check Substitute -1 for y
-7y le 14
-7 ( -1 ) le 14
7 le 14
8 b __ 5 gt -1
b __ 5 ( 5 ) gt -1 ( 5 )
b gt -5
-5-6-7-8 -4 -3 -2-1 0 1 2
Check Substitute 0 for b
b __ 5 gt -1
0 __ 5 gt
-1
0 gt -1
9 a -4t ge -80
b -4t ge -80
-4t ____ -4
le -80 ____ -4
t le 20
It will take the physicist 20 or fewer hours to change
the temperature of the metal
c The physicist would have to cool the metal for
more than 20 hours for the temperature of the
metal get cooler than -80deg C
10 You reverse the inequality symbol when you divide
or multiply both sides of an inequality by a negative
number
Independent Practice
11 x - 35 gt 15
_ + 35 _ +35
x gt 50
100 20 30 40 50 60 70 80 90100
Check Substitute 51 for x
x - 35 gt 15
51 minus 35 gt 15
16 gt 15
12 193 + y ge 201
_ -193 _ minus193
y ge 8
10 2 3 4 5 6 7 8 9 10
Check Substitute 9 for y
193 + y ge 201
193 + 9 ge 201
202 ge 201
13 - q
__ 7 ge -1
- q
__ 7 ( -7 ) le -1 ( -7 )
q le 7
8 9 105 6 70 1 2 3 4
Check Substitute ndash14 for q
- q
__ 7 ge -1
- -14 ____ 7 ge
-1
2 ge -1
14 -12x lt 60
-12x _____ -12
gt 60 ____ -12
x gt -5
0-10-9 -8 -7 -6 -5 -4 -3 -2-1
Check Substitute -4 for x
-12x lt 60
-12 ( -4 ) lt 60
48 lt 60
15 5 gt z -3
_ +3 _ +3
8 gt z
z lt 8
10 2 3 4 5 6 7 8 9 10
Check Substitute 7 for z
5 gt z - 3
5 gt 7 - 3
5 gt 4
Copyright copy by Houghton Mifflin Harcourt 44 All rights reserved
16 05 le y __
8
05 ( 8 ) le y __
8 ( 8 )
4 le y
y ge 4
8 9 105 6 70 1 2 3 4
Check Substitute 8 for y
05 le y __
8
05 le 8 __
8
05 le 1
17 Write and solve an inequality
Let x = the number of inches
12 + x le 28
_ -12 _ -12
x le 16
The puppy will grow at most 16 inches more
18 Write and solve an inequality
Let w = the total weight of the kittens
w __ 7 lt 35
w __ 7 ( 7 ) lt 35 ( 7 )
w lt 245
The possible combined weights of the kittens is any
weight less than 245 ounces but greater than 0
19 Write and solve an inequality
Let s = the number of sides
6s le 42
6s ___ 6 le 42 ___
6
s le 7
The length of a side is at most 7 inches
20 Write and solve an inequality
Let x = the amount Tom needs to spend
3025 + x ge 50
_ -3025 _ -3025
x ge 1975
Tom needs to spend at least $1975
21 Write and solve an inequality
Let w = the width of the region
155w ge 1705
155w ______ 155
ge 1705 _____ 155
w ge 11
The possible width of the region is at least 11 feet
22 Write and solve an inequality
Let t = the number of seconds
thinsp-12t lt -120
-12t _____ -12
gt -120 _____ -12
t gt 10
No let t be the number of seconds the descent
takes the inequality is ndash12t lt -120 so t gt 10 so
the submarinersquos descent takes 10 seconds or more
23 Write and solve an inequality
Let s = the amount of spinach
3s le 10
3s ___ 3 le 10 ___
3
s le 3 1 __ 3
The greatest amount of spinach she can buy is 3 1 __ 3
pounds
24 Write and solve an inequality
Let m = the amount of money Gary has
m ___ 05
le 55
m ___ 05
( 05 ) le 55 ( 05 )
m le 275
Gary has at most $275
25 Write and solve an inequality
Let x = the number of pounds of onions
125x le 3
125x _____ 125
le 3 ____ 125
x le 24
No 125x le 3 x le 24 so 24 pounds of onions is
the most Florence can buy 24 lt 25 so she cannot
buy 25 pounds
Focus on Higher Order Thinking
26 If you divide both sides of -7z ge 0 by -7 and do
not reverse the inequality symbol you get z ge 0
This is incorrect because if you choose a value from
the possible solutions such as z = 1 and substitute
it into the original equation you get -7 ge 0 which is
not true
27 x gt 9 for each inequality in each case the number
added to x is 9 less than the number on the right
side of each inequality so x gt 9 is the solution
28 Find the formula for the volume of a rectangular
prism
V = lwh
Write and solve an inequality
Let h = the height in inches
( 13 ) ( 1 __ 2 ) h lt 65
65h lt 65
65h ____ 65
lt 65 ___ 65
h lt 10
All heights greater than 0 in and less than 10 in
( 13 ) ( 1 __ 2 ) h lt 65 65h lt 65 h lt 10 A height cannot
be 0 or less than 0 so h gt 0 and h lt 10
Copyright copy by Houghton Mifflin Harcourt 45 All rights reserved
LESSON 72Your Turn
3 Let a represent the amount each member must
raise
Number of members 45
Starting amount $1240
Target amount $6000
starting number amount each is greater target
amount plus of members times member than or amount
must raise equal to
darr darr darr darr darr darr darr $1240 + 45 middot a ge $6000
Equation 1240 + 45a ge 6000
4 Let n represent the greatest number of rides Ella
can go on
Starting amount $40
Admission price $6
Cost for each ride $3
admission cost for number is less starting
price plus each ride times of rides than or amount
equal to
darr darr darr darr darr darr darr $6 + $3 middot n le $40
Equation 6 + 3n le 40
5 x is the solution of the problem the quantity you
are looking for
3x means that for a reason given in the problem
the quantity you are looking for is multiplied by 3
+ 10 means that for a reason given in the problem
10 is added to 3x
gt 30 means that after multiplying the solution x by
3 and adding 10 to it the result must be greater
than 30
Sample answer An exam consists of one essay
question worth 10 points and several multiple choice
questions worth 3 points each If Petra earns full
points on the essay question how many multiple
choice questions must she get right in order to get
a score greater than 30 points
6 x is the solution of the problem the quantity you are
looking for
5x means that for a reason given in the problem
the quantity you are looking for is multiplied by 5
-50 means that for a reason given in the problem
50 is subtracted from 5x
le 100 means that after multiplying the solution x by
5 and subtracting 50 from it the result must be less
than or equal to 100
Sample answer Miho has $100 to spend on her
garden She spends $50 on gardening supplies
Vegetable plants cost $5 each What is the greatest
number of plants she can buy
Guided Practice
1
- -- -
-
lt
++++++
+ + ++ + +
+
2
---
gt
+ + ++ + +
+ + ++ + +
+ + +
3 Let a represent the amount each member must
raise
Amount to be raised $7000
Amount already raised $1250
Number of members 92 amount number of amount each is greater target
already plus members times member than or amount
raised raises equal to
darr darr darr darr darr darr darr 1250 + 92 times a ge 7000
The inequality that represents this situation is
1250 + 92a ge 7000
4 x is the solution of the problem 7x is the solution
multiplied by 7 -18 means that 18 is subtracted
from 7x le 32 means that the result can be no
greater than 32
5 Sample answer Alexa has $32 to spend on T-shirts
for her friends She has a gift card worth $18 T-shirts
cost $7 each How many T-shirts can Alexa buy
6 Sample answer Choose a variable to represent
what you want to find Decide how the information in
the problem is related to the variable Then write an
inequality
Independent Practice
7 number possible amount is
of times amount each minus for more $200
friends friend earns supplies than
darr darr darr darr darr darr darr 3 middot a - $28 gt $200
3a + 28 gt 200
Let a = possible amount each friend earned
8 cost of number cost of less than amount
bagel times of bagels plus cream or equal Nick
cheese to has
darr darr darr darr darr darr darr $075 middot n + $129 le $700
075n + 129 le 700
Let n = the number of bagels Nick can buy
9 number max amount amount less than total amount
of shirts times each shirt minus of gift or equal Chet can
can cost certificate to spend
darr darr darr darr darr darr darr 4 sdot a - 25 le 75
4a - 25 le 75Let a = the maximum amount each shirt can cost
Copyright copy by Houghton Mifflin Harcourt 46 All rights reserved
10 number of number number of is less total
seats in plus of rows on times seats in than equal number
balcony ground floor one row equal to of people
darr darr darr darr darr darr darr 120 + 32 middot n le 720
120 + 32n le 720
Let n = the number of people in each row
11 amount commission amount greater than earning
earned per plus rate times of sales or equal to for this
month month
darr darr darr darr darr darr darr 2100 + 005 middot s ge 2400
2100 + 005s ge 2400
Let s = the amount of her sales
12 number number average greater
of cans plus of days times number of than goal
collected cans per day
darr darr darr darr darr darr darr 668 + 7 n gt 2000
668 + 7n gt 2000
Let n = the average number of cans collected each
day
13 cost per cost per number of less than total amount
month plus CD times CDs she or equal spent in
buys to a month
darr darr darr darr darr darr darr
$7 + $10 middot c le $100
7 + 10c le 100
Let c = the number of CDs Joanna buys
14 cost of cost for number of less than total amount
belt plus each times shirts he or equal of money
shirt can buy to Lionel has
darr darr darr darr darr darr darr
$22 + $17 middot n le $80
22 + 17n le 80
Let n = the number of shirts he can buy
15 Sample answer Mr Craig is buying pizzas for the
7th grade field day He can spend up to $130 and
needs 15 pizzas He has a $20 coupon How much
can he spend per pizza $10 or less per pizza
16 ldquoat leastrdquo in this case means m ge 25
17 ldquono greater thanrdquo in this case means k le 9
18 ldquoless thanrdquo in this case means p lt 48
19 ldquono more thanrdquo in this case means b le -5
20 ldquoat mostrdquo in this case means h le 56
21 ldquono less thanrdquo in this case means w ge 0
22 The average score of the three tests Marie has
already taken and the three she will still take
is given by
95 + 86 + 89 + 3s
________________ 6
where s is the average score on the three remaining
tests
This value needs to be greater than or equal to 90
so the inequality can be written as
95 + 86 + 89 + 3s
________________ 6 ge 90 or
95 + 86 + 89 + 3s ge 540 or
270 + 3s ge 540
Focus on Higher Order Thinking
23 5 + 10 lt 20 Sample answer If the combined length
of two sides of a triangle is less than the length of
the third side the two shorter sides will not be long
enough to form a triangle with the third side Here
the combined length of 5 ft and 10 ft is 15 ft not
enough to make a triangle
24 -m gt 0 Sample answer Since m is less than 0 it
must be a negative number -m represents the
opposite of m which must be a positive number
since the opposite of a negative number is positive
So -m gt 0
25 n gt 1 __ n if n gt 1
n lt 1 __ n if n lt 1
n = 1 __ n if n = 1
LESSON 73
Your Turn
1 Model the inequality
++
++++
+++
++++
++++
+++
gt
Add seven -1-tiles to both sides of the mat
++
++++
+++
++++
++++
+++
gt
- -- -- --
- -- -- --
Remove zero pairs from both sides of the mat
++
++++
gt
Divide each side into equal groups
++
++++
gt
Copyright copy by Houghton Mifflin Harcourt 47 All rights reserved
The solution is x gt 2
+ + +gt
2 Model the inequality
+++++
----
+++++
+ +++++
ge
Add four +1-tiles to both sides of the mat
+++++
----
+++++
+ ++
++++
+++
++++
ge
Remove zero pairs from the left side of the mat
+++++
+++++
+ +++++
++++
ge
Divide each side into equal groups
+++++
+++++
+ +++++
++++
ge
The solution is h ge 3
+ + + +ge
3 Use inverse operations to solve the inequality
5 - p
__ 6 le 4
5 - 5 - p
__ 6 le 4 - 5
thinsp- p
__ 6 le -1
thinsp-6 ( - p
__ 6 ) ge -6 ( -1 )
p ge 6
Graph the inequality and interpret the circle and
arrow
0 1 4 5 72 3 6 8 9 10
Joshua has to run at a steady pace of at least 6 mih
4 Substitute each value for v in the inequality
3v - 8 gt 22
v = 9 v = 10 v = 11
3 ( 9 ) - 8 gt 22 3 ( 10 ) - 8 gt 22 3 ( 11 ) - 8 gt 22
Evaluate each expression to see if a true inequality
results
3 ( 9 ) - 8 gt 22 3 ( 10 ) - 8 gt
22 3 ( 11 ) - 8 gt
22
27 - 8 gt 22 30 - 8 gt
22 33 - 8 gt
22
19 gt 22 22 gt
22 25 gt
22
not true not true true
v = 11
5 Substitute each value for h in the inequality
5h + 12 le -3
h = -3 h = -4 h = -5
5 ( -3 ) + 12 le -3 5 ( -4 ) + 12 le -3 5 ( -5 ) + 12 le -3
Evaluate each expression to see if a true inequality
results
5 ( -3 ) + 12 le -3 5 ( -4 ) + 12 le
-3 5 ( -5 ) + 12 le
-3
-15 + 12 le -3 -20 + 12 le
-3 -25 + 12 le
-3
-3 le -3 -8 le
-3 -13 le
-3
true true true
h = -3 h = -4 h = -5
Copyright copy by Houghton Mifflin Harcourt 48 All rights reserved
Guided Practice
1 Remove 4 +1-tiles from both sides then divide each
side into 3 equal groups the result is x lt 3
2 Use inverse operations to solve the inequality
5d - 13 lt 32
5d - 13 + 13 lt 32 + 13
5d lt 45
5d ___ 5 lt 45 ___
5
d lt 9
Graph the inequality
20 6 84 10 12 14 16 18 20
3 Use inverse operations to solve the inequality
-4b + 9 le -7
-4b + 9 - 9 le -7 - 9
-4b le -16
-4b ____ -4
ge -16 ____ -4
b ge 4
Graph the inequality
20 6 84 10 12 14 16 18 20
4 Substitute each value for m in the inequality
2m + 18 gt - 4
m = -12 m = -11 m = -10
2 ( -12 ) + 18 gt -4 2 ( -11 ) + 18 gt -4 2 ( -10 ) + 18 gt -4
Evaluate each expression to see if a true inequality
results
2 ( -12 ) + 18 gt -4 2 ( -11 ) + 18 gt
- 4 2 ( -10 ) + 18 gt
- 4
- 24 + 18 gt -4 - 22 + 18 gt
- 4 - 20 + 18 gt
- 4
- 6 gt - 4 - 4 gt
- 4 - 2 gt
- 4
not true not true true
m = -10
5 Substitute each value for y in the inequality
- 6y + 3 ge 0
y = 1 y = 1 __ 2 y = 0
-6 ( 1 ) + 3 ge 0 -6 ( 1 __ 2 ) + 3 ge 0 -6 ( 0 ) + 3 ge 0
Evaluate each expression to see if a true inequality
results
-6 ( 1 ) + 3 ge 0 - 6 ( 1 __
2 ) + 3 ge
0 - 6 ( 0 ) + 3 ge
0
-6 + 3 ge 0 -3 + 3 ge
0 0 + 3 ge
0
-3 ge 0 0 ge
0 3 ge
0
not true true true
y = 1 __ 2
y = 0
6 Solve the inequality
65 - 4t ge 15
65 - 65 - 4t ge 15 - 65
-4t ge -5
-4t ____ -4
le -5 ___ -4
t le 125
Graph the inequality
0 05 1 15 2 25
Lizzy can spend from 0 to 125 h with each student
No 15 h per student will exceed Lizzyrsquos available
time
7 Sample answer Apply inverse operations until you
have isolated the variable If you multiply or divide
both sides of the inequality by a negative number
reverse the direction of the inequality symbol
Independent Practice
8 2s + 5 ge 49
2s + 5 - 5 ge 49 - 5
2s ge 44
2s ___ 2 ge 44 ___
2
s ge 22
10 14 1612 18 20 22 24 26 28 30
9 -3t + 9 ge -21
-3t + 9 - 9 ge -21 -9
-3t ge -30
-3t ____ -3
le -30 ____ -3
t le 10
ndash2ndash4ndash6ndash8ndash10 0 2 4 6 8 10
10 55 gt -7v + 6
55 - 6 gt -7v + 6 - 6
49 gt - 7v
49 ___ -7 lt -7v ____ -7
v gt -7
-10-9 -8 -7 -6 -5 -4 -3 -2 -1 0
11 21 1 __ 3 gt 3m - 2 2 __
3
21 1 __ 3 + 2 2 __
3 gt 3m - 2 2 __
3 + 2 2 __
3
24 gt 3m
24 ___ 3 gt 3m ___
3
8 gt m or m lt 8
0 1 4 5 72 3 6 8 9 10
12 a ___ -8
+ 15 gt 23
a ___ -8
+ 15 - 15 gt 23 - 15
a ___ -8
gt 8
-8 ( a ___ -8
) lt -8 ( 8 )
a lt -64
-70 -68 -66 -64 -62 -60
Copyright copy by Houghton Mifflin Harcourt 49 All rights reserved
13 f __ 2 - 22 lt 48
f __ 2 - 22 + 22 lt 48 + 22
f __ 2 lt 70
2 ( f __ 2 ) lt 2 ( 70 )
f lt 140
100 110 120 130 140 150
14 -25 + t __ 2 ge 50
-25 + 25 + t __ 2 ge 50 + 25
t __ 2 ge 75
2 ( t __ 2 ) ge 2 ( 75 )
t ge 150
130 140 150 160 170 180
15 10 + g ___
-9 gt 12
10 - 10 + g ___
-9 gt 12 - 10
g ___
-9 gt 2
-9 ( g ___
-9 ) lt -9 ( 2 )
g lt -18
-20 -18 -14 -12 -10-16
16 252 le -15y + 12
252 - 12 le -15y + 12 - 12
24 le - 15y
24 ____ -15
ge -15y
_____ -15
y le -16
-20 -18 -14 -12 -10-16
17 -36 ge -03a + 12
-36 - 12 ge -03a + 12 - 12
-48 ge -03a
-48 _____ -03
le -03a ______ -03
a ge 16
10 11 12 13 14 16 17 18 19 2015
18 80 - 2w ge 50
80 - 80 - 2w ge 50 - 80
- 2w ge -30
-2w ____ -2
le -30 ____ -2
w le 15
The width is a positive number no greater than
15 inches the possible widths in inches will be 10
11 12 13 14 and 15
19 Inequality 7n - 25 ge 65
7n - 25 ge 65
7n - 25 + 25 ge 65 + 25
7n ge 90
7n ___ 7 ge 90 ___
7
n ge 12 6 __ 7
Grace must wash at least 13 cars because n must
be a whole number
Focus on Higher Order Thinking
20 No Sample answer If x lt x - 1 then subtracting
x from both sides of the inequality 0 lt -1 That is
untrue so no value of x can be less than x - 1
21 a
10 3 42 5 6 7 8 9 10
b
10 3 42 5 6 7 8 9 10
c A number cannot simultaneously be less than 2
and greater than 7 Therefore there is no number
that satisfies both inequalities
d Consider the graph of x gt 2 and x lt 7
The solution includes all the numbers on the
number line so the solution set is all numbers
22 Sample answer Joseph might have reasoned that n
was first multiplied by 2 then increased by 5 to give
a result less than 13 Working backward he would
have subtracted 5 from 13 ( to get 8 ) then divided by
2 ( to get 4 ) giving n lt 4 Shawnee would have
followed these same steps but would have used a
variable and invers operations
MODULE 7
Ready to Go On
1 n + 7 lt -3
thinsp _ -7
_ -7
n lt -10
2 5p ge -30
5p
___ 5 ge -30 ____
5
p ge -6
3 14 lt k + 11
_ -11 _ -11
3 lt k
4 d ___ -3
le minus6
( -3 ) ( d ) ge ( -3 ) ( -6 )
d ge 18
Copyright copy by Houghton Mifflin Harcourt 50 All rights reserved
5 c - 25 le 25
_ +25 _ +25
c le 5
6 12 ge -3b
12 ___ -3
le -3b _____ -3
-4 le b
7 Let n be the number of minimum points Jose must
score 562 + n ge 650
Solve the inequality
562 + n ge 650
_ -562 _ -562
n ge 88
8 Let t be the number of minutes Lainey can descend
-20 - 20t ge -100
9 2s + 3 gt 15
_ -3 _ -3
2s gt 12
2s ___ 2
gt 12 ___ 2
s gt 6
10 - d ___ 12
- 6 lt 1
_ +6 _ +6
- d ___ 12
lt 7
12 ( - d ___ 12
) lt 12 ( 7 )
-d lt 84
d gt -84
11 -6w - 18 ge 36
_ +18 _ +18
thinsp-6w ge 54
-6w _____ -6
le 54 ___ -6
w le -9
12 z __ 4 + 22 le 38
_ -22 _ -22
z __ 4 le 16
4 ( z __ 4 ) le 4 ( 16 )
z le 64
13 b __ 9 - 34 lt -36
_ +34 _ +34
b __ 9 lt -2
9 ( b __ 9 ) lt 9 ( -2 )
b lt -18
14 -2p + 12 gt 8
-12 ____
-12 ____
-2p gt -4
-2p
____ -2 lt -4 ___
-2
p lt 2
15 Sample answer Look for key words or phrases
that indicate inequality such as ldquogreater thanrdquo
ldquoless thanrdquo ldquoat mostrdquo or ldquoat leastrdquo
Copyright copy by Houghton Mifflin Harcourt 51 All rights reserved
MODULE 8 Modeling Geometric Figures
Are You Ready
1 3x + 4 = 10
3x + 4 - 4 =10 - 4
3x = 6
3x ___ 3 = 6 __
3
x = 2
2 5x - 11 = 34
5x - 11 + 11 = 34 + 11
5x = 45
5x ___ 5 = 45 ___
5
x = 9
3 -2x + 5 = -9
-2x + 5 - 5 = -9 - 5
-2x = -14
-2x ____ -2
= -14 ____ -2
x = 7
4 -11 = 8x + 13
-11 - 13 = 8x + 13 - 13
-24 = 8x
-24 ____ 8 = 8x ___
8
-3 = x
5 4x - 7 = -27
4x - 7 + 7 = -27 + 7
4x = -20
4x ___ 4 = -20 ____
4
x = -5
6 1 __ 2 x + 16 = 39
1 __ 2 x + 16 - 16 = 39 - 16
1 __ 2 x = 23
( 2 ) 1 __ 2 x = ( 2 ) 23
x = 46
7 12 = 2x - 16
12 + 16 = 2x - 16 + 16
28 = 2x
28 ___ 2 = 2x ___
2
14 = x
8 5x - 15 = -65
5x - 15 + 15 = -65 + 15
5x = -50
5x ___ 5 = -50 ____
5
x = -10
9 x __ 5 = 18 ___
30
x times 30 = 5 times 18
30x = 90
30x ____ 30
= 90 ___ 30
x = 3
10 x ___ 12
= 24 ___ 36
x times 36 = 12 times 24
36x = 288
36x ____ 36
= 288 ____ 36
x = 8
11 3 __ 9 = x __
3
3 times 3 = 9 times x
9 = 9x
9 __ 9 = 9x ___
9
1 = x
12 14 ___ 15
= x ___ 75
14 times 75 = 15 times x
1050 = 15x
1050 _____ 15
= 15x ____ 15
70 = x
13 8 __ x = 14 ___ 7
8 times 7 = x times 14
56 = 14x
56 ___ 14
= 14x ____ 14
4 = x
14 14 ___ x = 2 __ 5
14 times 5 = x times 2
70 = 2x
70 ___ 2 = 2x ___
2
35 = x
15 5 __ 6 = x ___
15
5 times 15 = 6 times x
75 = 6x
75 ___ 6 = 6x ___
6
125 = x
Solutions KeyGeometry
UNIT
4
Copyright copy by Houghton Mifflin Harcourt 52 All rights reserved
16 81 ___ 33
= x ____ 55
81 times 55 = 33 times x
4455 = 33x
4455 _____ 33
= 33x ____ 33
135 = x
LESSON 81
Your Turn
6 Length 132 in times 5 ft ____ 3 in
= 22 ft
Width 6 in times 5 ft ____ 3 in
= 10 ft
Area 10 ft ( 22 ft ) = 220 square feet
Guided Practice
1
Blueprint
length (in)3 6 9 12 15 18
Actual
length (ft)5 10 15 20 25 30
a The wall is 30 feet long
b 25 ft times 3 in ____ 5 ft
= 15 in
2 The width is 7 in times 4 ft ____ 2 in
= 14 ft and the length is
14 in times 4 ft ____ 2 in
= 28 ft and the area is
28 ft ( 14 ft ) = 392 square feet
3 Length 10 cm times 5 m _____ 2 cm
= 25 m
Width 6 cm times 5 m _____ 2 cm
= 15 m
Area 25 m ( 15 m ) = 375 square meters
4 a
b Length is 36 m and width is 24 m using both
scales
5 If the scale drawing is complete and accurate you
can use it to find any length or area of the object of
the drawing
Independent Practice
6 a 2 in times 40 cm ______ 1 in
= 80 cm
15 in times 40 cm ______ 1 in
= 60 cm
The dimensions of the painting are 80 cm by 60 cm
b 80 cm times 60 cm = 4800 c m 2
c 80 cm times 1 in _______ 254 cm
asymp 315 in
60 cm times 1 in _______ 254 cm
asymp 236 in
The dimensions of the painting are approximately
315 in by 236 in
d 315 in times 236 in asymp 743 i n 2
7 120 ft times 1 unit _____ 5 ft
= 24 units
75 ft times 1 unit _____ 5 ft
= 15 units
The dimensions of the drawing are 24 units by
15 units
8 Sample answer 2 in6 ft 1 in3 ft and 1 in1 yd
9 Because the scale is 10 cm1 mm and because
10 cm is longer than 1 mm the drawing will be
larger
10 a Let r represent the scale
54 ft times r = 810 m
r = 810 m ______ 54 ft
r = 150 m ______ 1 ft
The scale is 1 ft = 150 m
b 54 ft times 12 in _____ 1 ft
= 648 in
Let b represent the number of tiny bricks
b = 648 in times 1 brick ______ 04 in
b = 162 bricks
The model is 162 tiny bricks tall
11 a Let h represent the height of the model
h = 30 ft times 126 cm _______ 1 ft
h = 378 cm
Let n represent the number of toothpicks
n = 378 cm times 1 toothpick
_________ 63 cm
n = 6 toothpicks
The model will be 6 toothpicks tall
b 378 cm times 1 swab ______ 76 cm
asymp 5 swabs
The model will be about 5 cotton swabs tall
Focus on Higher Order Thinking
12 If the area of the scale drawing is 100 square cm
then one side is 10 cm Let s represent the side
length of the actual floor
s = 10 cm times 2 ft _____ 1 cm
s = 20 ft
So the area is 20 ft(20 ft) = 400 ft 2
The ratio of areas is 100 square cm 400 square feet
or 1 square cm 4 square feet
Copyright copy by Houghton Mifflin Harcourt 53 All rights reserved
13 Decide on the new scale yoursquod like to use Then find
the ratio between the old scale and the new scale
and redraw the scale drawing accordingly For
example the ratio could be 13 In that case you
would redraw the dimensions at three times the
original size
14 Sample answer 1 __ 4 in 8 ft 40 ft by 24 feet 960 f t
2
LESSON 82
Guided Practice
1 The two angles 45deg and a right angle or 90deg with
the included side 8 cm determine the point at which
the sides meet so a unique triangle is formed
2 The sum of the measures of the two short sides
4 + 3 = 7 The sum is less than the measure of the
long side 11 so no triangle is formed
3 The two angles 40deg and 30deg with the included side
7 cm determine the point at which the sides meet
so a unique triangle is formed
4 The sum of the measures of the two short sides
6 + 7 = 13 The sum is greater than the measure of
the long side 12 so a unique triangle is formed
5 Sample answer Segments with lengths of 5 in
5 in and 100 in could not be used to form a
triangle
Independent Practice
6 A figure with side lengths of 3 centimeters and 6
centimeters and an included angle of 120deg deter-
mine the length of the third side of a triangle and so
produce a unique triangle
6 cm
3 cm120˚
7 The side lengths proposed are 15 ft 21 ft and 37 ft
The sum of the measures of the two shorter sides
15 + 21 = 36 So the sum is less than the measure
of the long side 37 No such triangle can be created
8 The three angle measures can be used to form
more than one triangle The sign and the scale
drawing are two different-sized triangles with the
same angle measures
Focus on Higher Order Thinking
9 More than one triangle can be formed Two triangles
can be created by connecting the top of the 2-in
segment with the dashed line once in each spot
where the arc intersects the dashed line The
triangles are different but both have side lengths of
2 in and 1 1 __ 2 in and a 45deg angle not included
between them
10 The third side has a length of 15 in The third side
must be congruent to one of the other two sides
because the triangle is isosceles The third side
cannot measure 6 in because 6 + 6 is not greater
than 15 So the third side must measure 15 in
LESSON 83
Guided Practice
1 triangle or equilateral triangle
2 rectangle
3 triangle
4 rainbow-shaped curve
5 Sample answer Draw the figure and the plane
Independent Practice
6 Sample answer A horizontal plane results in cross
section that is a circle A plane slanted between
horizontal and vertical results in an oval cross
section A vertical plane through the cylinder results
in a rectangle A vertical plane along an edge of the
cylinder results in a line cross section
7 You would see circles or ovals with a cone but not
with a pyramid or prism
Focus on Higher Order Thinking
8 The plane would pass through the cube on a
diagonal from the top to the bottom of the cube
9 a It is a circle with a radius of 12 in
b The cross sections will still be circles but their
radii will decrease as the plane moves away from
the spherersquos center
10 The dimensions of two faces are 12 in by 8 in two
are 8 in by 5 in and two are 12 in by 5 in the
volume is 480 in 3
11 Sample answer If you think of a building shaped like
a rectangular prism you can think of horizontal
planes slicing the prism to form the different floors
Copyright copy by Houghton Mifflin Harcourt 54 All rights reserved
LESSON 84
Your Turn
5 Supplementary angles sum to 180deg Sample answer angFGA and angAGC
6 Vertical angles are opposite angles formed by two
intersecting lines
Sample answer angFGE and angBGC
7 Adjacent angles are angles that share a vertex and
one side but do not overlap Sample answer
mangFGD and mangDGC
8 Complementary angles are two angles whose
measures have a sum of 90deg Sample answer
mangBGC and mangCGD
9 Because mangFGE = 35deg and angFGE and angBGC are
vertical angles that means mangBGC = 35deg also
Because lines _
BE and _
AD intersect at right angles
mangBGD = 90deg so mangBGC + mangCGD = 90deg which means
mangBGC + mangCGD = 90deg 35deg + x = 90deg 35deg minus 35deg + x = 90deg minus 35deg x = 55deg
mangCGD = 55deg
10 angJML and angLMN are supplementary so their
measures sum to 180deg mangJML + mangLMN = 180deg 3x + 54deg = 180deg 3x + 54deg - 54deg = 180deg - 54deg 3x = 126deg
3x ___ 3 = 126deg ____
3
x = 42deg
mangJML = 3x = 3 ( 42deg ) = 126deg
11 Sample answer You can stop at the solution step
where you find the value of 3x because the measure
of angJML is equal to 3x
Guided Practice
1 angUWV and angUWZ are complementary angles
2 angUWV and angVWX are adjacent angles
3 angAGB and angDGE are vertical angles
so mangDGE = 30deg
4 mangCGD + mangDGE + mangEGF = 180deg 50deg + 30deg + 2x = 180deg 80deg + 2x = 180deg 2x = 100deg mangEFG = 2x = 100deg
5 mangMNQ + mangQNP = 90deg 3x - 13deg + 58deg = 90deg so 3x + 45deg = 90degThen 3x = 45deg and x = 15deg mangMNQ = 3x - 13deg = 3 ( 15deg ) - 13deg = 45deg - 13deg = 32deg
6 Sample answer Let mangS = x Write and solve an
equation ( x + 3x = 180deg ) to find x then multiply the
value by 3
Independent Practice
7 Sample answer angSUR and angQUR are adjacent
They share a vertex and a side
8 Sample answer angSUR and angQUP
9 Sample answer angTUS and angQUN
10 mangQUR = 139deg Sample answer angSUR and angSUP
are supplementary so mangSUP = 180deg - 41deg = 139deg angSUP and angQUR are vertical angles so they are
congruent and mangQUR = mangSUP = 139deg
11 mangRUQ is greater Sample answer angSUR and
angNUR are complementary so
mangNUR = 90deg - 41deg = 49deg mangTUR = 41deg + 90deg which is less than
mangRUQ = 49deg + 90deg
12 Because angKMI and angHMG are vertical angles their
measures are equal
mangKMI = mangHMG
84 = 4x
84 ___ 4 = 4x ___
4
x = 21deg
13 Because angKMH and angKMI are supplementary
angles the sum of their measures is 180deg mangKMH + mangKMI = 180deg x + 84 = 180
x + 84 - 84 = 180 - 84
x = 96
mangKMH = 96deg
14 Because angCBE and angEBF are supplementary
angles the sum of their measures is 180deg mangCBE + mangEBF = 180deg x + 62 = 180
x + 62 - 62 = 180 - 62
x = 118
mangCBE = 118deg
15 Because angABF and angFBE are complementary
angles the sum of their measures is 90deg mangABF + mangFBE = 90deg x + 62 = 90
x + 62 - 62 = 90 - 62
x = 28
mangABF = 28deg
16 Because angCBA and angABF are supplementary
angles the sum of their measures is 180deg mangABF = 28deg so
mangCBA + mangABF = 180deg x + 28 = 180 - 28
x + 28 - 28 = 152
mangCBA = 152deg
Copyright copy by Houghton Mifflin Harcourt 55 All rights reserved
17 If the two angles are complementary the sum of
their angles is 90degmangA + mangB = 90deg ( x + 4deg ) + x = 90deg 2x + 4deg = 90deg _ -4deg _ -4deg 2x = 86deg
2x ___ 2 = 86deg ___
2
x = 43degBecause x = mangB then mangB = 43deg and
mangA = 43deg + 4deg so mangA = 47deg
18 If the two angles are supplementary the sum of their
angles is 180degmangD + mangE = 180deg 5x + x = 180deg 6x = 180deg
6x ___ 6 = 180deg ____
6
x = 30degBecause x = mangE then mangE = 30deg and
mangD = 30deg x 5 so mangD = 150deg
19 If the two angles are complementary the sum of
their angles is 90deg When angles are divided into
minutes and seconds one apostrophe signifies a
minute and two apostrophes signifies a second
mangJ + mangK = 90deg0000
48deg268+ mangK = 90deg0000
_ -48deg268 _ -48deg268
mangK = 41deg3352
mangK = 41deg3352 or mangK = 41 degrees
33 minutes 52 seconds
Focus on Higher Order Thinking
20 Yes a parking lot can be built because the measure
of angle K is 180deg - ( 50deg + 90deg ) or 40deg which is
greater than 38deg
21 Disagree the sum of the measures of a pair of
complementary angles is 90deg So the measure of
each angle must be less than 90deg 119deg gt 90deg
22 a The sum of mangA and its complement will be 90deg Let x represent the complement
mangA + x = 90deg 77deg + x = 90deg _ -77deg = _ -77deg x = 13deg The complement of mangA has a measure of 13deg
and a complement of a complement of mangA
would have an angle equal to mangA or 77deg b A complement of a complement of an angle has
the same measure of the angle itself Let xdeg be
the measure of an angle The measure of a
complement of the angle is ( 90 - xdeg ) A complement of that angle has a measure of
( 90 - ( 90 - xdeg ) ) = ( 90 - 90 + xdeg ) = xdeg
MODULE 8
Ready to Go On
1
Living
roomKitchen Office Bedroom Bedroom Bathroom
Actual
ℓ times w ( ft ) 16 times 20 12 times 12 8 times 12 20 times 12 12 times 12 6 times 8
Blueprint
ℓ times w ( in ) 4 times 5 3 times 3 2 times 3 5 times 3 3 times 3 15 times 2
2 No The side lengths proposed are 8 cm 4 cm and
12 cm The sum of the measures of the two shorter
sides 4 + 8 = 12 So no such triangle can be
created
3 The longest side could be 15 cm because 20 cm is
too long given the lengths of the other sides
4 A circle is a possible cross section of a sphere
A point is another
5 A circle rectangle oval and line are possible cross
sections of a cylinder
6 mangBGC and mangFGE are vertical angles so
mangFGE = 50deg
7 If the two angles are complementary the sum of
their angles is 90deg mangS + mangY = 90deg
( 2 ( mangY ) - 30deg ) + mangY = 90deg 3 ( mangY ) - 30deg = 90deg _ +30deg = _ +30deg 3 ( mangY ) = 120deg
3 ( mangY ) ________ 3 = 120deg ____
3
mangY = 40deg
mangY = 40deg
8 Sample answer You can use scale drawings to plan
rooms or gardens
Copyright copy by Houghton Mifflin Harcourt 56 All rights reserved
MODULE 9 Circumference Area and Volume
Are You Ready
1 416
_ times 13
1248
_ +thinsp4160
5408
5408
2 647
_ times thinsp04
2588
2588
3 705
_ times thinsp94
2820
_ +thinsp63450
66270
6627
4 256
_ timesthinsp049
2304
_ +thinsp10240
12544
12544
5 1 __ 2 ( 14 ) ( 10 )
7 ( 10 )
70 i n 2
6 ( 35 ) ( 35 )
1225 ft 2
7 ( 8 1 __ 2 ) ( 6 )
17 ___ 1 2 sdot 6 3 __
1
51 i n 2
8 1 __ 2 ( 125 ) ( 24 )
1 __ 2 ( 24 ) ( 125 )
( 12 ) ( 125 )
15 m 2
LESSON 91
Your Turn
3 d = 11 cm
C = πd
C asymp 314 ( 11 )
C asymp 3454
The circumference is about 3454 cm
6 C = πd
44 asymp 314d
44 ____ 314
asymp d
d asymp 1401 yards
Divide the diameter of the garden by the digging
rate
1401 divide 7 = 2001
It takes Lars about 2 hours to dig across the garden
Guided Practice
1 d = 9 in
C asymp 314 ( 9 )
C asymp 2826 in
2 r = 7 cm
C = 2πr
C asymp 2 ( 22 ___ 7 ) ( 7 )
C asymp 44 cm
3 d = 25 m
C = πd
C asymp 314 ( 25 )
C asymp 785 m
4 r = 48 yd
C = 2πr
C asymp 2 ( 314 ) ( 48 )
C asymp 3014 yd
5 r = 75 in
C = 2πr
C asymp 2 ( 314 ) ( 75 )
C asymp 471 in
6 Find the diameter
C = πd
66 asymp 314d
66 ____ 314
asymp 314d _____ 314
21 asymp d
Find the cost
Carlos needs 21 + 4 = 25 feet of rope
25 times $045 = $1125
Carlos will pay $1125 for the rope
7 Because C = π yd and C = πd d = 1 yd then
r = 05 yd
d = 1 yd
8 Because C = 788 ft and C = 2πr
2πr = 788
2πr ___ 2π
= 788 ____ 2π
r asymp 788 _______ 2 ( 314 )
r asymp 1255 ft
d = 2r asymp 2 ( 1255 ft )
d asymp 2510 ft
9 d = 2r so r = d __ 2 asymp 34 ___
2
r asymp 17 in
C = πd asymp 314 ( 34 )
C = 1068 in
Copyright copy by Houghton Mifflin Harcourt 57 All rights reserved
10 Use the formula C = πd and substitute
314 for π and 13 for the diameter
Independent Practice
11 d = 59 ft
C = πd
C asymp 314 ( 59 )
C asymp 1853 ft
12 r = 56 cm
C = 2πr
C asymp 2 ( 22 ___ 7 ) ( 56 )
C asymp 352 cm
13 d = 35 in
C = πd
C asymp ( 22 ___ 7 ) ( 35 )
C asymp 110 in
14 Sample answer In exercises 12 and 13 the radius
or diameter is a multiple of 7
15 r = 94 ft
d = 2r = 2 ( 94 )
d = 188 ft
C = πd
C asymp 314 ( 188 )
C asymp 590 ft
16 d = 475 in
r = d __ 2 = 475 ____
2
r = 2375 in
C = πd
C asymp 314 ( 475 )
C asymp 14915 in
17 d = 18 in
r = d __ 2 = 18 ___
2
r = 9 in
C = πd
C asymp 314 ( 18 )
C asymp 5652 in
18 r = 15 ft
C = 2πr
C asymp 2 ( 314 ) ( 15 ) = 942 ft
The cost for edging is C times $075 per foot
so ( 942 ) ( 075 ) = 7065 or about $707
19 C = πd
C asymp ( 22 ___ 7 ) ( 63 )
C asymp 198 ft
The distance traveled is 12 times the
circumference of the Ferris wheel so
distance = 12 ( 198 ) or about 2376 ft
20 C = πd asymp 314 ( 2 )
C asymp 628 ft
Converting km to ft
2 km sdot ( 3280 ft _______
1 km ) = 6560 ft
6560 ft
_______ 628 ft
= 104459
The wheel makes about 1045 revolutions
21 The distance your friend walks is half the
circumference of the pond
1 __ 2 C = 1 __
2 πd asymp 1 __
2 sdot 314 ( 025 ) = 03925
Your friend walks approximately 03925 mi
The difference is 03925 - 025 = 01425
Your friend walks about 014 mi farther
22 Capitol Rotunda Dimensions
Height 180 ft
Circumference 3015 ft
Radius r = C ___ 2π asymp 3015
_______ 2 ( 314 )
asymp 48 ft
Diameter d = 2r = 2 ( 48 ) = 96 ft
Focus on Higher Order Thinking
23 The length of the fence is half the circumference
plus the diameter
1 __ 2 C = 1 __
2 πd asymp 1 __
2 sdot 314 ( 30 ) = 471
The total distance is 471 + 30 = 771 ft
The total cost is the length of fence times the cost
per linear foot
( 771 ft ) ( $925 _____
ft ) = $71318
It will cost about $71318
24 The circumference of the patio is
C = πd asymp 314 ( 18 ) = 5652 ft
Converting the length of one strand of lights from
inches to feet
( 54 in ) ( 1 ft _____ 12 in
) = 45 ft
To find the number of strands of lights divide the
circumference by the length of one strand
5652 ft _______ 45 ft
= 1256
Because Sam cannot buy a fraction of a strand he
must buy 13 strands
25 The distance is the difference in the circumferences
C inner
= πd asymp 314 ( 150 ) = 471 ft
The outer diameter is 150 ft + 2 ( 2 ft ) = 154 ft
C outer
= πd asymp 314 ( 154 ) = 48356 ft
The difference is 48356 - 471 = 1256 ft
It is about 1256 ft farther
26 No The circumference of the larger gear is about
πd asymp 314 ( 4 ) = 1256 inches The circumference of
the smaller gear is about πd asymp 314 ( 2 ) = 628
inches So the circumference of the larger gear is
628 inches more than the circumference of the
smaller gear
Copyright copy by Houghton Mifflin Harcourt 58 All rights reserved
27 Pool B about 057 m or 184 ft Sample answer
24 feet asymp 732 m so the diameter of Pool B is
greater and the circumference is greater
314 ( 75 ) - 314 ( 732 ) = 314 ( 018 ) asymp 057
057 m asymp 187 ft
LESSON 92
Your Turn
4 A = π r 2 A = π ( 10 ) 2
A asymp 314 ( 10 ) 2
A asymp 314 sdot 100
A asymp 314 f t 2
Guided Practice
1 r = d __ 2 = 14 ___
2 = 7 m
A = π r 2 A = π ( 7 ) 2
A asymp 314 ( 7 ) 2
A asymp 314 sdot 49
A asymp 1539 m 2
2 A = π r 2 A = π ( 12 ) 2
A asymp 314 ( 12 ) 2
A asymp 314 sdot 144
A asymp 4522 m m 2
3 r = d __ 2 = 20 ___
2 = 10 yd
A = π r 2 A = π ( 10 ) 2
A asymp 314 ( 10 ) 2
A asymp 314 sdot 100
A asymp 314 y d 2
4 A = π r 2 A = π ( 8 ) 2
A asymp 314 ( 8 ) 2
A asymp 314 sdot 64
A asymp 20096 i n 2
5 r = d __ 2 = 12 ___
2 = 6 cm
A = π r 2 A = π ( 6 ) 2
A asymp 314 ( 6 ) 2
A asymp 314 sdot 36
A asymp 11304 c m 2
6 r = d __ 2 = 13 ___
2 = 65 in
A = π r 2 A = π ( 65 ) 2
A asymp 314 ( 65 ) 2
A asymp 314 sdot 4225
A asymp 13267 i n 2
7 C = 4π = 2πr
4π ___ 2π
= 2πr ___ 2π
r = 2
A = π r 2 A = π ( 2 ) 2
A = 4π square units
8 C = 12π = 2πr
12π ____ 2π
= 2πr ___ 2π
r = 6
A = π r 2 A = π ( 6 ) 2
A = 36π square units
9 C = π __ 2 = 2πr
π __ 2 divide 2π = 2πr ___
2π
π __ 2 sdot 1 ___
2π = r
1 __ 4 = r
A = π r 2
A = π ( 1 __ 4 ) 2 = π ( 1 ___
16 )
A = π ___ 16
square units
10 A = π r 2 = 64π
π r 2 ___ π = 64π ____ π
r 2 = 64
r = 8
C = 2πr
= 2π ( 8 )
=16π yd
11 A = π r 2
Independent Practice
12 r = d __ 2 = 10 ___
2 = 5 in
A = π r 2 A = π ( 5 ) 2
A asymp 314 ( 5 ) 2
A asymp 314 sdot 25
A asymp 785 i n 2
13 A = π r 2 A = π ( 16 ) 2
A asymp 314 ( 16 ) 2
A asymp 314 sdot 256
A asymp 80384 c m 2
14 The area of the window is half the area of a circle of
diameter 36 in
r = d __ 2 = 36 ___
2 = 18 in
A semicircle
= 1 __ 2 π r 2
A semicircle
= 1 __ 2 π ( 18 ) 2
A semicircle
asymp 1 __ 2 ( 314 ) ( 18 ) 2
A semicircle
asymp 05 sdot 314 sdot 324
A asymp 50868 i n 2
Copyright copy by Houghton Mifflin Harcourt 59 All rights reserved
15 If the point ( 3 0 ) lies on the circle and the origin is
its center the radius of the circle is 3 units
A = π r 2 A = π ( 3 ) 2
A asymp 314 ( 3 ) 2
A asymp 314 sdot 9A asymp 2826 square units
16 The difference in areas is given by
A r = 75 mi
- A r = 50 mi
π ( 75 ) 2 - π ( 50 ) 2
= π ( 7 5 2 minus 5 0 2 ) = π ( 5625 minus 2500 ) = π ( 3125 ) asymp 98125
The area of the relayed signal is about 9813 mi 2
greater
17 The area of the field which is not reached by the
sprinkler is the area of the field minus the area
reached by the sprinkler or s 2 minus π r 2 where
s = 12 m and r is the radius of the circular area The
diameter of the circle is equal to a side of the field
12 m so the radius is 12 ___ 2 = 6 m So
s 2 minus π r 2 = 1 2 2 minus π ( 6 ) 2
= 144 minus π ( 36 )
asymp 144 minus 11304 = 3096
The area not reached by the sprinkler is
approximately 3096 m 2
18 No the area of the regular pancake is 4π in 2 and the
area of the silver dollar pancake is π in 2 so the area
of the regular pancake is 4 times the area of the
silver dollar pancake
19 No the top of the large cake has an area 9 times
that of the small cake The area of the top of the
large cake is 144π in 2 and that of the small cake is
16π in 2
20 Sample answer First find the radius of the circle by
using the formula C = 2πr Then substitute the
radius into the formula for the area of a circle
21 The 18-inch pizza is a better deal because it costs
about $20
_____ π ( 9 ) 2
asymp $008 or 8 cents per square inch
while the 12-inch pizza costs about $10
_____ π ( 6 ) 2
asymp $009
or 9 cents per square inch
22 a Because the bear can walk at a rate of 2 miles
per hour and was last seen 4 hours ago the
radius of the area where the bear could be found
is given by ( 2 miles per hour ) ( 4 hours ) = 8 miles
A = π r 2 = π ( 8 ) 2
= π ( 64 )
asymp 20096
The searchers must cover an area of about
201 mi 2
b The additional area is the difference in areas of
circles with radii ( 2 miles per hour ) ( 5 hours )
= 10 miles and the original 8 miles
A new
minus A old
= π ( 10 ) 2 - π ( 8 ) 2
= π ( 1 0 2 - 8 2 ) = π ( 100 - 64 )
= π ( 36 ) asymp 11304
The searchers would have to cover about 113 mi 2
more area
Focus on Higher Order Thinking
23 No the combined area is 2π r 2 while the area of a
circle with twice the radius is 4π r 2
24 The area is multiplied by a factor of n 2
25 To find the part that is the bullrsquos-eye take the ratio of
the area of the bullrsquos-eye to that of the whole target
The radius of the bullrsquos-eye is 3 __ 2 = 15 in and
the radius of the whole target is 15 ___ 2 = 75 in
A
bullrsquos-eye ________
A whole target
=
π ( 15 ) 2 ______
π ( 75 ) 2
= ( 15 ) 2
_____ ( 75 ) 2
= 225 _____ 5625
= 004
The bullrsquos-eye is 004 or 4 of the whole target
LESSON 93
Your Turn
2 The figure can be separated into a rectangle and
two right triangles
The dimensions of the large rectangle are
length = 8 + 3 = 11 ft width = 4 ft
The dimensions of the two small triangles are
base = 3 ft height = 2 ft ( upper triangle ) base = 3 ft height = 3 ft ( lower triangle ) The area of the rectangle is
A = ℓw = 11 sdot 4 = 44 f t 2
The area of the upper triangle is
A = 1 __ 2 bh = 1 __
2 sdot 3 sdot 2 = 3 f t 2
The area of the lower triangle is
A = 1 __ 2 bh = 1 __
2 sdot 3 sdot 3 = 45 f t 2
Therefore the total area of the figure is
44 + 3 + 45 = 515 f t 2
3 The figure can be separated into a square and a
semicircle
Each side of the square is equal to 10 m
The radius of the semicircle is half the diameter
or 10 ___ 2 = 5 m
The area of the square is
A = s 2 = 1 0 2 = 100 m 2
The area of the semicircle is
A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 5 ) 2
A asymp 1 __ 2 sdot 314 sdot 25
A asymp 3925 m 2
Therefore the approximate total area of the figure is
100 + 3925 = 13925 m 2
Copyright copy by Houghton Mifflin Harcourt 60 All rights reserved
4 The composite figure is made up of a rectangle and two
semicircles which can be combined to form one circle
The dimensions of the rectangle are
length = 5 ft width = 4 ft
The diameter of the circle is 4 ft so the radius is
4 __ 2 = 2 ft
The area of the rectangle is
A = ℓw = 5 sdot 4 = 20 f t 2
The area of the circle is
A = π r 2 A asymp 314 sdot ( 2 ) 2
A asymp 314 sdot 4A asymp 1256 f t 2
The approximate total area is the sum of these
two areas
20 + 1256 = 3256 f t 2
Because the glass costs $28 per square foot
multiply the total area by the cost per square foot
( 3256 f t 2 ) ( $28 ____
f t 2 ) = $91168
It will cost about $91168 to replace the glass
Guided Practice
1 Separate the figure into a triangle a rectangle and
a parallelogram
Find the area of each figure
For triangle A = 1 __ 2 bh = 1 __
2 ( 4 ) ( 2 ) = 4
For rectangle A = ℓw = ( 5 ) ( 3 ) = 15
For parallelogram A = bh = ( 5 ) ( 3 ) = 15
Triangle 4 cm 2 rectangle 15 cm
2 parallelogram
15 cm 2
Step 3 Find the area of the composite figure
4 + 15 + 15 = 34 cm 2
The area of the irregular shape is 34 cm 2
2 Method 1
A 1 = ℓw A
2 = ℓw
= 12 sdot 9 = 20 sdot 9 = 108 = 180
Total area = 288 c m 2
Method 2
A 1 = ℓw A
2 = ℓw
= 9 sdot 8 = 12 sdot 8 = 72 = 216
Total area = 288 c m 2
3 Separate the figure into a trapezoid with h = 5 ft
b 1 = 7 ft and b 2 = 4 ft and a parallelogram with
base = 4 ft and height = 4 ft
For trapezoid A = 1 __ 2 h ( b
1 + b
2 )
A = 1 __ 2 ( 5 ) ( 7 + 4 )
A = 1 __ 2 ( 5 ) ( 11 ) = 275 f t 2
For parallelogram A = bh = ( 4 ) ( 4 ) = 16 f t 2
Find the area of the composite figure
275 + 16 = 435 ft 2
Multiply the total area by the cost per square foot to
find the cost
( 435 f t 2 ) ( $225 _____
f t 2 ) = $9788
4 The first step is separating the composite figure into
simpler figures
Independent Practice
5 Area of square A = s 2 = 2 6 2 = 676 i n 2
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 13 ) 2
A asymp 1 __ 2 sdot 314 sdot 169
A asymp 26533 i n 2
The approximate total area is the sum
676 + 26533 = 94133 in 2
6 a The floor of the closet is a composite of a
rectangle with length = 10 ft and width = 4 ft and
a triangle with base = 6 ft and height = 3 + 4 = 7 ft
Area of rectangle A = ℓw = 10 sdot 4 = 40 f t 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 6 sdot 7
A = 1 __ 2 sdot 42
A = 21 f t 2
The total area is the sum
40 + 21 = 61 f t 2
b The cost is the area multiplied by the cost per
square foot
( 61 f t 2 ) ( $250 _____
f t 2 ) = $15250
7
O 42-2-4
2
-4
y
A (-2 4) B (0 4)
C (2 1)D (5 1)
E (5 -2)F (-2 -2)
The area can be thought of as a composite of a
trapezoid and a rectangle
For trapezoid Let b 1 of the trapezoid be the
segment from the point ( -2 1 ) point C with length
4 units b 2 be from point A to point B with length
2 units and height equal to 3 units
For rectangle The corners of the rectangle are
( -2 1 ) D E and F Let the length of the rectangle
be 7 units and the width be 3 units
Area of trapezoid
A = 1 __ 2 h ( b
1 + b
2 )
A = 1 __ 2 ( 3 ) ( 4 + 2 )
A = 1 __ 2 ( 3 ) ( 6 ) = 9 square units
Copyright copy by Houghton Mifflin Harcourt 61 All rights reserved
Area of rectangle A = ℓw
A = 7 sdot 3 A = 21 square units
The total area is the sum
9 + 21 = 30 square units
8 The field is a composite of a square with side = 8 m
a triangle with base = 8 m and height = 8 m and a
quarter of a circle with radius = 8 m
Area of square A = s 2 = 8 2 = 64 m 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 8 sdot 8
A = 1 __ 2 sdot 64
A = 32 m 2
Area of quarter circle A = 1 __ 4 π r 2
A asymp 1 __ 4 sdot 314 sdot ( 8 ) 2
A asymp 1 __ 4 sdot 314 sdot 64
A asymp 5024 f t 2
The approximate total area is the sum
64 + 32 + 5024 = 14624 m 2
9 The bookmark is a composite of a rectangle with
length = 12 cm and width = 4 cm and two
semicircles which combine to form a full circle with
diameter = 4 cm so radius = 4 __ 2 = 2 cm
Area of rectangle A = ℓw = 12 sdot 4 = 48 c m 2
Area of circle A = π r 2 A asymp 314 sdot ( 2 ) 2
A asymp 314 sdot 4 A asymp 1256 c m 2
The approximate total area is the sum
48 + 1256 = 6056 cm 2
10 The pennant is a composite of a rectangle with
length = 3 ft and width = 1 ft and a triangle with
base = 1 ft and height = 1 ft
Area of rectangle A = ℓw = 3 sdot 1 = 3 f t 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 1 sdot 1
A = 1 __ 2 sdot 1
A = 05 f t 2
The area of one pennant is the sum
3 + 05 = 35 ft 2
Alex is making 12 pennants so the total area of all
12 pennants is 12 sdot 35 = 42 ft 2
The cost for the pennants will be the total area times
the fabric cost per square foot
( 42 f t 2 ) ( $125 _____
f t 2 ) = $5250
11 The area of the square is the total area minus the
area of triangle
325 ft 2 - 75 ft 2 = 25 ft 2
The area of a square is A = s 2 so s 2 = 25 f t 2
Because 5 sdot 5 = 25 the length of each side of the
square is 5 ft
Focus on Higher Order Thinking
12 The area of the garden can be found from counting
squares there are 18 full squares and 4 half-squares
for a total of 20 square units Each square unit will
grow about 15 carrots So Christina will grow about
20 ( 15 ) or 300 carrots
13 To find the length of the three sides of the square
subtract the lengths of the two sides of the triangle
from the perimeter The total length of three sides of
the square is 56 - 20 = 36 in Divide by 3 to find
that the length of one side and the base of the
triangle is equal to 12 in The total area of the figure
is the area of the square plus the area of the
triangle
Area of square A = s 2 = 1 2 2 = 144 i n 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 12 sdot 8
A = 1 __ 2 sdot 96
A = 48 i n 2
The total area is the sum
144 + 48 = 192 in 2
14 Think of the scarf as a rectangle minus two
semicircles The rectangle has length = 28 in and
width = 15 in The circle has diameter = 15 in so
its radius is 15 ___ 2 = 75 in
Area of rectangle A = ℓw = 28 sdot 15 = 420 i n 2
Area of circle A = π r 2 A asymp 314 sdot ( 75 ) 2
A asymp 314 sdot 5625
A asymp 176625 i n 2
The total area is the difference
420 - 176625 = 243375 in 2 or 243 3 __
8 i n 2
15 a The window is a composite of a square and a
semicircle Because each square in the window
has an area of 100 in 2 the length of each side is
10 in So each side of the square portion of the
entire window has length 10 sdot 4 = 40 in The
diameter of the semicircle is also 40 in so
the radius is 40 ___ 2 = 20 in
Area of square A = s 2 = 4 0 2 = 1600 i n 2
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 20 ) 2
A asymp 1 __ 2 sdot 314 sdot 400
A asymp 628 i n 2
The approximate total area is the sum
1600 + 628 = 2228 in 2
Copyright copy by Houghton Mifflin Harcourt 62 All rights reserved
b The shade is a composite of a rectangle and
a semicircle The length of the rectangle is equal
to the length of one side of the square portion
of the window plus 2 sdot 4 inches for a total of
40 + 2 sdot 4 = 48 in
The height of the rectangular portion of the shade
is equal to 4 times the length of one side of the
square portion of the window plus 4 inches for a
total of 40 + 4 = 44 in
The diameter of the semicircle at the top is the
same as the length of the bottom of the shade
48 in so the radius = 48 ___ 2 = 24 in
Area of rectangle A = ℓw = 48 sdot 44 = 2112 i n 2
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 24 ) 2
A asymp 1 __ 2 sdot 314 sdot 576
A asymp 90432 i n 2
The approximate total area of the shade is
the sum
2112 + 90432 asymp 3016 in 2
LESSON 94
Your Turn
3 Find the area of a base
B = l times w
= 9 times 2
= 18 square inches
Find the perimeter of the base
P = 2 ( 9 ) + 2 ( 2 )
= 18 + 4 = 22 inches
Find the surface area
S = Ph + 2B
S = 22 ( 1 1 __ 2 ) + 2 ( 18 )
= 33 + 36
= 69
The surface area of the box is 69 square inches
4 Find the area of the base of the larger prism
B = times w
= 12 times 12
= 144 square inches
Find the perimeter of the base
P = 4 ( 12 )
= 48 inches
Find the surface area of the larger prism
S = Ph + 2B
S = 48 ( 12 ) + 2 ( 144 )
= 576 + 288
= 864 square inches
Find the area of the base of the smaller prism
B = l times w
= 8 times 8
= 64 square inches
Find the perimeter of the base
P = 4 ( 8 )
= 32 inches
Find the surface area of the smaller prism
S = Ph + 2B
S = 32 ( 8 ) + 2 ( 64 )
= 256 + 128
= 384 square inches
Add the surface areas of the two prisms and
subtract the areas not stained (the bottom of the
larger prism and the smaller prism and an equal
area of the top of the larger prism where the smaller
prism sits) Surface area = 864 + 384 - 144 - 64
- 64 = 976 The surface area of the part of the plant
stand that she will stain is 976 square inches
Guided Practice
1 Perimeter of base = 5 + 5 + 8 = 18
Perimeter of base = 18 ft
Height = 7 ft
Base area = 1 __ 2 ( 3 ) ( 8 ) = 12 ft 2
Surface area
S = ( 18 ft ) ( 7 ft ) + 2 ( 12 ft 2 ) = 150 ft 2
2 Find the area of a base of the cube
B = l times w
= 25 times 25
= 625 m 2
Find the perimeter of the base of the cube
P = 4 ( 25 )
= 10 m
Find the surface area of the cube
S = Ph + 2B
S = 10 ( 25 ) + 2 ( 625 )
= 25 + 125
= 375
Surface area of cube
S = 375 m 2
Find the area of a base of the rectangular prism
B = l times w
= 11 times 9
= 99 m 2
Find the perimeter of the base of the rectangular
prism
P = 2 ( 11 ) + 2 ( 9 )
= 22 + 18
= 40 m
Find the surface area of the rectangular prism
S = Ph + 2B
S = 40 ( 7 ) + 2 ( 99 )
= 280 + 198
= 478
Surface area of rectangular prism
S = 478 m 2
Find the overlapping area the bottom of the cube
A = ( 25 ) ( 25 ) = 625
Overlapping area A = 625 m 2
Surface area of composite figure
= 375 + 478 -2 ( 625 ) = 503 m 2
3 Find the surface area of each of the prisms that
make up the solid Add the surface areas and
subtract the areas of any parts that are not on the
surface
Copyright copy by Houghton Mifflin Harcourt 63 All rights reserved
Independent Practice
4 Find the area of a base
B = l times w
= 10 times 3
= 30 in 2
Find the perimeter of the base
P = 2 ( 10 ) + 2 ( 3 )
= 20 + 6
= 26 in
Find the surface area
S = Ph + 2B
S = 26 ( 4 ) + 2 ( 30 )
=104 + 60
= 164 in 2
She needs 164 in 2 of wrapping paper
5 Find the area of the base
B = l times w
= 20 times 15
= 300 cm 2
Find the perimeter of the base
P = 2 ( 20 ) + 2 ( 15 )
= 40 + 30
= 70 cm
Find the surface area of the box
S = Ph + 2B
S = 70 ( 9 ) + 2 ( 300 )
= 630 + 600
= 1230 cm 2
Find the surface area of the top and sides
1230 - 300 = 930 cm 2
Find the area of a glass tile
Area of tile = 5 times 5 = 25 mm 2
Convert cm 2 to mm
2
930 cm 2 times 100 mm
2 ________
1 cm 2 = 93000 mm
2
Find the number of tiles needed
93000 divide 25 = 3720
3720 tiles are needed
6 Find the area of the L-shaped base
Area of L-shape = 2 times 1 + 3 times 1
= 2 + 3 = 5 in 2
Find the perimeter of the L-shaped base
Perimeter = 3 + 3 + 1 + 2 + 2 + 1
= 12 in
Find the surface area
S = Ph + 2B
S = 12 ( 3 ) + 2 ( 5 )
= 36 + 10
= 46 in 2
The surface area of each brace is 46 in 2
7 Find the area of the triangular prism
Perimeter = 25 + 25 + 3 = 8 ft
Base area = 1 __ 2 ( 2 ) ( 3 ) = 3 ft 2
Surface area = Ph + 2B
= 8 ( 4 ) + 2 ( 3 )
= 32 + 6 = 38 ft 2
Find the area of the rectangular prism
Perimeter = 2 ( 3 ) + 2 ( 4 ) = 14 ft
Base area = 3 times 4 = 12 ft 2
Surface area = Ph + 2B
= 14 ( 2 ) + 2 ( 12 )
= 28 + 24 = 52 ft 2
Add the surface areas of the two prisms and
subtract the parts not on the surface
Surface area = 38 + 52 - 12 - 12 = 66 ft 2
The total surface area of the doghouse is 66 ft 2
8 Treat the figure as ( 1 ) a composite of two triangular
prisms and one rectangular prism or ( 2 ) a prism
with a base that is a trapezoid
9 Find the area of the trapezoid base
Area of trapezoid = 1 __ 2 ( b
1 + b
2 ) h
1 __ 2 ( 16 + 48 ) 12 = 384 in
2
Find the perimeter of the base
P = 48 + 20 + 16 + 20 = 104 in
Find the surface area
S = Ph + 2B
S = 104 ( 24 ) + 2 ( 384 )
= 2496 + 768
= 3264 in 2
The surface area of the ramp is 3264 in 2
10 Find the area of the base of the larger prism
B = l times w
= 7 times l
= 7 ft 2
Find the perimeter of the base
P = 2 ( 7 ) + 2 ( 1 )
= 14 + 2
= 16 ft
Find the surface area of the larger prism
S = Ph + 2B
S = 16 ( 2 ) + 2 ( 7 )
= 32 + 14
= 46 f t 2
Find the area of the base of the smaller prism
B = l times w
= 1 times 1
= 1 ft 2
Find the perimeter of the base
P = 2 ( 1 ) + 2 ( 1 )
= 2 + 2 = 4 ft
Find the surface area of the smaller prism
S = Ph + 2B
S = 4 ( 3 ) + 2 ( 1 )
= 12 + 2
= 14 ft 2
Add the surface areas of the two prisms and
subtract the parts not on the surface
Surface area = 46 + 14 - 1 - 1 = 58 ft 2
The surface area of the stand is 58 ft 2
11 Find the number of cans of paint needed
58 divide 25 = 232
It takes 2 full cans and 1 partial can so 3 cans are
needed
Find the cost of 3 cans of paint
3 times 679 = 2037
No they need 3 cans which will cost $2037
Copyright copy by Houghton Mifflin Harcourt 64 All rights reserved
12 Find the area of the base of the box
B = l times w
= 27 times 24
= 648 cm 2
Find the perimeter of the base
P = 2 ( 27 ) + 2 ( 24 )
= 54 + 48
= 102 cm
Find the surface area of the box
S = Ph + 2B
S = 102 ( 10 ) + 2 ( 648 )
= 1020 + 1296
= 2316 cm 2
2316 cm 2 will be covered with paper
13 Area of the original base B = l times w
Area of the new base = 2l times 2w = 4lw = 4B
Perimeter of the original = 2l + 2w
Perimeter of the new = 2 ( 2l ) + 2 ( 2w ) =
2 ( 2l + 2w ) = 2P
Original S = Ph + 2B
New S = 2Ph + 2 ( 4B )
No Ph doubles and 2B quadruples S more than
doubles
Focus on Higher Order Thinking
14 Find the area of the base of the prism
B = l times w
= 25 times 25
= 625 ft 2
Find the perimeter of the base
P = 4 ( 25 )
= 10 ft
Find the surface area of the prism
S = Ph + 2B
S = 10 ( 35 ) + 2 ( 625 )
= 35 + 135
= 485 ft 2
Find the surface area less the area of the bottom
surface of the prism
485 - 625 = 4225 ft 2
Find what percent of the surface area less the area
of the bottom is compare to the total surface area
4225 _____ 485
times 100 asymp 87
Sample answer She would be painting about 87
of the total surface area so she will use about 87
of the total amount of paint
15
Circumference ofcircle πd = πtimes4
r = 2 in
9 in
Find the area of the circle base
A = πr 2
asymp 31 4 ( 2 ) 2 = 1256 in 2
Find the circumference of the circle
C = πd
asymp 314 ( 4 ) = 1256 in 2
Find the area of the rectangle
Area asymp 9 times 1256 = 11304 in 2
Find the surface area of the cylinder
S = Ch + 2B
asymp 1256 ( 9 ) + 2 ( 1256 ) = 13816 in 2
Round to the nearest tenth 1382 in 2
The surface area of the oatmeal box is
approximately 1382 in 2
Find the amount of cardboard for 1500 boxes
1500 times 1382 = 207300 in 2
Convert square inches to square feet and round to
the nearest whole number
( 207300 in 2 ) 1 ft 2 _______
144 in 2 asymp 1440 ft 2
It would take about 1440 ft 2 of cardboard
16 Each face has 9 squares 1 cm by 1 cm so S =
54 cm 2 The surface area stays the same when one
or more corner cubes are removed ( Fig 2 3 ) because the number of faces showing is still the
same In Fig 4 S increases because 2 more faces
show
LESSON 95
Your Turn
2 Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 24 ) 7
= 84 m 2
Find the volume of the prism
V = Bh
= ( 84 ) ( 22 )
= 1848 m 3
The volume of the prism is 1848 m 3
5 Find the base area B of the trapezoidal prism
B = 1 __ 2 ( b 1 + b 2 ) h
= 1 __ 2 ( 8 + 12 ) 10
= 1 __ 2 ( 20 ) 10 = 100 cm
2
Find the volume of the prism
V = Bh
= ( 100 ) ( 22 )
= 2200 cm 3
The volume of the prism is 2200 cm 3
7 Find the volume of each prism
Find the base area B of the rectangular prism
B = bh
= ( 13 ) 13
= 169 in 2
Find the volume of the rectangular prism
V = Bh
= ( 169 ) ( 30 )
= 5070 in 3
Copyright copy by Houghton Mifflin Harcourt 65 All rights reserved
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 9 ) 13
= 585 in 2
Find the volume of the triangular prism
V = Bh
= ( 585 ) ( 30 )
= 1755 in 3
Find the sum of the volumes
5070 + 1755 = 6825 in 3
The volume of the composite figure is 6825 in 3
Guided Practice
1 B = 1 __ 2 bh = 1 __
2 ( 8 ) ( 3 ) = 12 ft 2
V = Bh = ( 12 times 7 ) ft 3 = 84 ft 3
2 B = 1 __ 2 ( b 1 + b 2 ) h = 1 __
2 ( 15 + 5 ) 3 = 30 m
2
V = Bh = ( 30 times 11 ) m 3 = 330 m 3
3 Find the base area B of the rectangular prism
B = bh
= ( 4 ) 6 = 24 ft 2
Find the volume of the rectangular prism
V = Bh
= ( 24 ) ( 12 ) = 288 ft 3
The volume of the rectangular prism = 288 ft 3
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 6 ) 4 = 12 ft 2
Find the volume of the triangular prism
V = Bh
= ( 12 ) ( 6 ) = 72 ft 3
The volume of the triangular prism = 72 ft 3
Find the sum of the volumes
288 + 72 = 360 ft 3
The volume of the composite figure = 360 ft 3
4 Find the base area B of the rectangular prism
B = bh
= ( 40 ) ( 50 ) = 2000 ft 2
Find the volume of the rectangular prism
V = Bh
= ( 2000 ) ( 15 ) = 30000 ft 3
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 40 ) ( 10 ) = 200 ft 2
Find the volume of the triangular prism
V = Bh
= ( 200 ) ( 50 ) = 10000 ft 3
Find the sum of the volumes
30000 + 10000 = 40000 ft 3
The volume of the barn is 40000 ft 3
5 Find the base area B of the trapezoidal prism
B = 1 __ 2 ( b 1 + b 2 ) h
= 1 __ 2 ( 10 + 12 ) 5
= 1 __ 2 ( 22 ) 5 = 55 cm
2
Find the volume of the trapezoidal prism
V = Bh
= ( 55 ) ( 7 ) = 385 cm 3
The volume of the container is 385 cm 3
6 Find the volume of each prism using the formula
V = Bh Then add the volumes of all the prisms
Independent Practice
7 The area of the base of the prism is given 35 in 2
Find the volume of the prism
V = Bh
= ( 35 ) ( 5 ) = 175 in 3
The volume of the trap is 175 in 3
8 The shape of the ramp is triangular prism
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 7 ) ( 6 ) = 21 in
2
Find the volume of the triangular prism
V = Bh
= ( 75 ) ( 7 ) = 525 in 3
The volume of the ramp is 525 in 3
9 Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 8 ) ( 4 ) = 16 ft 2
Find the volume of the triangular prism
V = Bh
= ( 16 ) ( 24 ) = 384 ft 3
The space contained within the goal is 384 ft 3
10 Find the base area B of the trapezoidal prism
B = 1 __ 2 ( b 1 + b 2 ) h
= 1 __ 2 ( 7 + 5 ) 4
= 1 __ 2 ( 12 ) 4 = 24 in
2
Find the volume of the trapezoidal prism
V = Bh
= ( 24 ) ( 8 ) = 192 in 3
The volume of the gift box is 192 in 3
11 Find the volume of the triangular prism
V = Bh
= ( 20 ) ( 15 ) = 300 in 3
The units for volume are incorrect the volume is
300 cubic inches
12 The area of the base of the hexagonal prism is
given B = 234 in 3
Find the volume of the hexagonal prism
V = Bh
= ( 234 ) ( 3 ) = 702 in 3
Copyright copy by Houghton Mifflin Harcourt 66 All rights reserved
Find the base area B of the rectangular prism
B = bh
= ( 3 ) ( 3 ) = 9 in 2
Find the volume of the rectangular prism
V = Bh
= ( 9 ) ( 3 ) = 27 in 3
Find the sum of the volumes
702 + 27 = 972 in 3
The volume of the figure is 972 in 3
13 Find the base area B of the larger rectangular prism
B = bh
= ( 75 ) 375 = 28125 m 2
Find the volume of the larger rectangular prism
V = Bh
= ( 28125 ) ( 75 ) asymp 21094 cm 3
Find the base area B of the smaller rectangular
prism
Find the measure of the base
15 - 75 = 75
Find the base area B of the larger rectangular prism
B = bh
= ( 75 ) 375 = 28125 m 2
Find the volume of the smaller rectangular prism
V = Bh
= ( 28125 ) ( 375 ) asymp 10547 cm 3
Find the sum of the volumes of the prisms
21094 + 10547 = 31641 m 3
The volume of the figure rounded to the nearest
hundredth is 31641 m 3
14 Find the volume of the hexagonal candle
V = Bh
= ( 21 ) ( 8 ) = 168 cm 3
Find the amount of wax Josie would have after
making the hexagonal candle
260 - 168 = 92 cm 3
Find the volume of the triangular candle
V = Bh
= ( 7 ) ( 14 ) = 98 cm 3
Find the amount of wax Josie would have after
making the hexagonal candle
260 - 168 = 92 cm 3
Find the area of the base of a triangular candle with
a height of 14 cm
V = Bh
92 = B ( 14 )
92 ___ 14
= B ( 14 ) _____ 14
6 8 ___ 14
= B asymp 657
No the area of the base of the triangular candle
must be less than or equal to about 657 cm 2
15 The base of trapezoidal prism is given 36 in 2 Find
the volume of the trapezoidal prism
V = Bh
= ( 36 ) ( 5 ) = 180 in 3
The base of triangular prism is given 32 in 2
Find the volume of the trapezoidal
prism V = Bh
= ( 32 ) ( 6 ) = 192 in 3
Triangular prism you get 192 in 3 for the same price
you would pay for 180 in 3 with the trapezoidal prism
Focus on Higher Order Thinking
16 Find the area of the base of the trapezoidal prism
V = Bh
286 = B ( 8 )
286 ____ 8 = B ( 8 )
3575 = B
Find the missing dimension of the base of the
trapezoidal prism
1 __ 2 ( 2 + b 2 ) 13 = 3575
1 __ 2 ( 2 + b 2 ) ( 13 ___
13 ) = 3575 _____
13
( 2 ) 1 __ 2 ( 2 + b 2 ) = ( 2 ) 275
2 + b 2 = 55
_ -2 _ -2
b 2 = 35 ft
The missing dimension is 35 ft
17 Find the area of the base of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 10 ) 6 = 30 cm
2
Find the volume of the triangular prism
V = Bh
= ( 30 ) ( 25 ) = 75 cm 3
Find the mass of the doorstop
mass asymp ( V in cm 3 ) ( 86 g
_____ cm
3 )
asymp ( 75 cm 3 ) ( 86 g
_____ cm
3 ) = 645 g
The volume of the doorstop is 75 cm 3 The mass is
about 645 g
18 If both the base and height of the triangular base are
tripled the area of the base is multiplied by 9
Tripling the height of the prism as well means the
volume of the prism is multiplied by 27
19 Use the formula for the volume of a trapezoidal
prism to find a set of dimensions that have a volume
of 120 cm 3
V = Bh
V = [ 1 __ 2 ( b 1 + b 2 ) h 1 ] h 2
120 ≟ [ 1 __ 2 ( 2 + 6 ) 4 ] 75
= [ 1 __ 2 ( 8 ) 4 ] 75
= [ 16 ] ( 75 ) = 120
Try another set of dimensions in the formula
V = Bh
V = [ 1 __ 2 ( b 1 + b 2 ) h 1 ] h 2
120 ≟ [ 1 __ 2 ( 1 + 7 ) 25 ] 12
= [ 1 __ 2 ( 8 ) 25 ] 12
= [ 10 ] 12 = 120
Copyright copy by Houghton Mifflin Harcourt 67 All rights reserved
Sample answers ( 1 ) height of trapezoid = 4 cm
base lengths = 2 cm and 6 cm height of prism
= 75 cm ( 2 ) height of trapezoid = 25 cm base
lengths = 1 cm and 7 cm height of prism = 12 cm
MODULE 9
Ready to Go On
1 r = 7 m A = π r 2 C = 2πr A asymp 314 sdot ( 7 ) 2
C asymp 2 sdot 314 sdot 7 A asymp 314 sdot 49
C asymp 4396 m A asymp 15386 m 2
2 d = 12 cm d = 6 cm so r = 12 ___ 2 = 6 ft
C = πd A = π r 2 C asymp 314 ( 12 ) A asymp 314 sdot ( 6 ) 2
C asymp 3768 cm A asymp 314 sdot 36
A asymp 11304 ft 2
3 The figure is a composite of a semicircle with
diameter = 16 m so radius is 16 ___ 2 = 8m and a
triangle with base = 16 m and height = 10 m
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 8 ) 2
A asymp 1 __ 2 sdot 314 sdot 64
A asymp 10048 m 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 16 sdot 10
A = 1 __ 2 sdot 160
A = 80 m 2
The total area is the sum
80 + 10048 = 18048 m 2
4 The figure is a composite of a parallelogram with
base = 20 cm and height = 45 cm and a rectangle
with length = 20 cm and height = 55 cm
Area of parallelogram A = bh
A = 20 sdot 45
A = 90 c m 2
Area of rectangle
A = ℓw = 20 sdot 55 = 110 c m 2
The total area is the sum
90 + 110 = 200 cm 2
5 Find the area of the triangular base
Area of triangle = 1 __ 2 bh
1 __ 2 ( 4 ) 3 = 6 cm 2
Find the perimeter of the base
P = 3 + 4 + 5 = 12 cm
Find the surface area
S = Ph + 2B
S = 12 ( 10 ) + 2 ( 6 )
thinsp=120 + 12
thinsp= 132 cm 2
Find the volume of the prism
V = Bh
= ( 6 ) 10
= 60 cm 3
6 Find the area of the composite base formed by a
rectangle and a triangle
Area of triangle = 1 __ 2 bh
1 __ 2 ( 4 ) 15 = 3 yd 2
Area of rectangle = bh
( 4 ) 2 = 8 yd 2
Area of the composite base 3 + 8 = 11 yd 2
Find the perimeter of the composite base
P = 4 + 2 + 25 + 25 + 2 = 13 yd
Find the surface area
S = Ph + 2B
S = 13 ( 25 ) + 2 ( 11 )
thinsp= 325 + 22
thinsp= 545 yd 2
The area of the base of the pentagonal prism
is given
B = 234 yd 3
Find the volume of the prism
V = Bh
= ( 11 ) 25
= 275 yd 3
7 Sample answer You can use a composite figure to
model a room then find surface area to decide how
much paint you need to paint the room
Copyright copy by Houghton Mifflin Harcourt 68 All rights reserved
Solutions KeyStatistics
unit
5MODULE 10 Random Samples and Populations
Are You Ready
1 x ___16
=45___40
40x=720
40x ____40
=720____40
x=18
2 x __5=1__
4
4x=5
4x ___4
=5__4
x=5__4=125
3 25___10
=x ___10
125=10x
125____10
=10x ____10
125=x
4 x __6
=2__9
9x= 12
9x ___9
=12___9
x=12___9=4__
3
5 4748495152575960range=60-47=13
6 4566689121213range=13-4=9
7 95979799100106108115range=115-95=20
8 121319273539476671range=71-12=59
9 mean=3+5+7+3+6+4+8+6+9+5_________________________________10
=56
10 mean=81+94+113+67+62+75____________________________6
=82
LESSON 101
Your Turn
4 Yeseveryemployeehadanequalchanceofbeingselected
5 Thequestionisbiasedsincecatsaresuggested
6 ThequestionisnotbiasedItdoesnotleadpeopletopickaparticularseason
Guided Practice
1 Method1ASampleanswer
Random Sample of Seventh Grade Male Students
Student Shoe SizeArturo 75
Jimmy 80
Darnell 90
Ping 75
Zach 85
Jamar 80
BSampleanswer
75+80+90+75+85+80___________________________6
=485____6
asymp81
Meanasymp81
Method2ASampleanswer
Student Shoe Size Student Shoe SizeReggie 85 Ling 85
Stan 80 Marcus 90
Alejandro 90 Tio 85
BSampleanswer
85+80+90+85+90+85____________________________6
=515____6 =86
Mean=size86
2Method1producesresultsthataremorerepresentativeoftheentirestudentpopulationbecauseitisarandomsample
3 Method2producesresultsthatarelessrepresentativeoftheentirestudentpopulationbecauseitisabiasedsample
4 YesSampleanswerWhatisyourfavoritecolor
5 Selectarandomsampleofsufficientsizethatrepresentsthepopulationandaskeachparticipantunbiasedquestions
Independent Practice
6 SampleanswerPaulrsquossamplewasbiasedMaybehisfriendsstudiedmorethanothers
7 SampleanswerNancyrsquossampledidnotincludeasmanystationsThereportcouldincludestationsnationwide
8 ItisabiasedsampleStudentswhoarenrsquotontheteamwonrsquotbeselected
CopyrightcopybyHoughtonMifflinHarcourt 69 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U5M10indd 69 103113 216 AM
9 Itisbiasedbecausestudentswhoarenrsquotinthatclasswonrsquotbeselected
10 Itisarandomsamplebecauseallseventhgradershaveanequalchanceofbeingselected
11 Itisarandomsamplebecausetheorganizationselectsnamesatrandomfromallregisteredvoters
12 Itisbiasedbecausebasketballismentioned
13 Jaersquosquestionisnotbiasedsinceitdoesnotsuggestatypeofarttostudents
Focus on Higher Order Thinking
14 CollinrsquosmethodbetterrepresentstheentirestudentpopulationbecauseheusedarandomsampleKarlrsquosmethodpickedpeoplethatcouldallbefriendsthatgotofootballgamestogetherThesamplemaynotbestrepresenttheentirestudentpopulation
15 a Every10thstudentoutof600meansthatBarbarasurveyed60studentsThiswasarandomsample
b 35___60
= x ____100
xasymp58
Thepercentis58____100
=58
ItappearsreasonablebecauseBarbarausedarandomsampleandsurveyedasignificantpercentofthestudents
16 CarloiscorrectTherearemanyvalidwaystoselectarepresentativesamplefromapopulation
LESSON 102
Your Turn
5 damagedMP3sinsample
______________________sizeofsample
=damagedMP3sinpopulation
________________________sizeofpopulation
6___50
= x_____3500
6sdot70______50sdot70
= x _____3500
420_____3500
= x_____3500
x=420420damagedMP3s
Guided Practice
1
6 7 8 9 10 11 12 13 14 1550 1 2 3 4
2 Orderthedatafindtheleastandgreatestvaluesthemedianandthelowerandupperquartiles
6 7 7 107 114 4 54
Leastvalue
4
Lower quartile
4
Median
65
Upper quartile
7
Greatestvalue11
Drawaboxplot
10 1550
3 Themostcommonagesofchildrenthatusethelibraryare4and7
4 Therangeofagesofchildrenthatusethelibraryisfrom4to11
5 Themedianageofchildrenthatusethelibraryis65
6 defectivephonesinsample
______________________sizeofsample
=defectivephonesinpopulation
_________________________sizeofpopulation
4___60
= x_____4200
4sdot70______60sdot70
= x_____4200
280_____4200
= x_____4200
x=280About280smartphonesintheorderarelikelytobedefective
7 infectedelkinsample
__________________sizeofsample
=infectedelkinpopulation
____________________sizeofpopulation
8___50
= x_____4500
8sdot90______50sdot90
= x_____4500
720_____4500
= x_____4500
x=720About720elkarelikelytobeinfected
8 YoucansetupproportionsusinginformationobtainedinarandomsampleofthepopulationForinstancethenumberofdefectivepartsinabatchcanbeusedtopredicthowmanypartswillbedefectiveinadifferent-sizebatch
divide060
divide060
CopyrightcopybyHoughtonMifflinHarcourt 70 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U5M10indd 70 103113 218 AM
Independent Practice
9 number of people with mispriced item in sample
_______________________________________ size of sample
=
number of people with mispriced item in one day
_______________________________________ size of population
4 ___ 50
= x ____ 600
4 sdot 12 ______ 50 sdot 12
= x ____ 600
48 ____ 600
= x ____ 600
x = 48
About 48 people are likely to have a mispriced item
10 number of boxes with at least one broken crayon in sample
_______________________________________________ size of sample
=
total number of boxes with at least one broken crayon
___________________________________________ size of population
2 ___ 20
= x ____ 130
2 sdot 65 _______ 20 sdot 65
= x ____ 130
13 ____ 130
= x ____ 130
x = 13
About 13 boxes will have at least one broken crayon
11 number of puppies
________________ size of sample
= total number of puppies
___________________ size of population
12 ___ 60
= x _____ 1200
12 sdot 20 ______ 60 sdot 20
= x _____ 1200
240 _____ 1200
= x _____ 1200
x = 240
About 240 puppies are in all of the cityrsquos animal
shelters
12 number of hawks building nests
__________________________ size of sample
= total number of hawks
__________________ size of population
12 ___ 72
= x ______ 10800
12 sdot 150 _______ 72 sdot 150
= x ______ 10800
1800
______ 10800
= x ______ 10800
x = 1800
About 1800 hawks are building nests
13 Yes this seems reasonable because 23 + 27
_______ 2 = 25
is the median of the data
14 Order the data
11 12 12 12 13 13 13 14 14 14 15 17 18 18
19 22
The total number of marathoners is 16 and of those
12 run 13 miles or more
12 ___ 16
= x ____ 100
12 sdot 625 ________ 16 sdot 625
= x ____ 100
75 ____ 100
= x ____ 100
x = 75
No The statement should say that 75 of female
marathoners run 13 or more miles a week
15
6 7 8 9 1050 1 2 3 4
Sample answer Most students at Garland have 2 or
fewer siblings
16 The box plot should show that at least 50 of the
ages are between 20 and 40 years of age
17 Kudrey needs to find the median and the lower and
upper quartiles and plot those points He assumed
all quartiles would be equally long when each
quartile represents an equal number of data values
Focus on Higher Order Thinking
18 Yes the least and greatest data values The median
and quartiles may or may not be actual data values
depending on how many values are in the data
19 A box plot Since every number is different a dot
plot would only have one dot over each value which
doesnrsquot give much information The box plot would
show the median the range and where data values
are concentrated if in fact they are
20 The typical salary at this company is $24000 the
median Yes it is misleading the average is thrown
off by the outlier value of $79000
Copyright copy by Houghton Mifflin Harcourt 71 All rights reserved
9 a 56 + 43 + 62 + 63 + 33 + 34 + 38 + 51 + 59 + 59
___________________________________________ 10
= 498
The average is 498 palms
b 498 sdot 64 = 31872
There are about 3187 palms on the entire farm
Focus on Higher Order Thinking
10 55 + 57 + 57 + 58 + 59 + 59 + 59 + 59 + 59 + 61 + 62 + 62 + 63 + 64 + 66
_________________________________________________________________ 15
= 60
The mean height is 60 inches Yes it is a good sample generated randomly and contains about 20 of the entire
population so it should provide a good estimate of the mean height of all competitors But taking more samples to
gauge the variability among the samples would make for a more valid estimate
11 Sample answer Answers will vary based on each studentrsquos results but should be about 13 or 14
12 Sample answer The larger the size of the random sample the more likely it is to represent the population
accurately
LESSON 103
Guided Practice
1 (1 600) 20
2 50 51 600
3 No In the sample 4 numbers (38 26 31 and 31)
represent defective batteries which is 20 of the
total In the shipment 50 out of 600 or about 8 of
the batteries are defective
4 Sample answer A too-small or non-random sample
is likely to pick unrepresentative data values
Independent Practice
5 Shop A 10 ___ 50
times 500 = 100
Shop B 23 ____ 100
times 500 = 115
Shop C 7 ___ 25
times 500 = 140
Shop A sells 100 whole-wheat bagels
Shop B sells 115 whole-wheat bagels
Shop C sells 140 whole-wheat bagels
6 From most to least likely B A C Shop Brsquos sample
would be the most representative because it
contained the most bagels Shop Crsquos sample would
be the least representative because it contained the
fewest bagels
7 She could use either the Shop A or Shop B sample
Both use a sufficient number of bagels to be
reasonably accurate The sample from Shop C uses
too few bagels to be accurate
8 2 of the 20 T-shirts in the sample are below quality
standards Because 2 ___ 20
times 1000 = 100 the predic-
tion would be that about 100 of the 1000 T-shirts are
below quality standards This is 1 1 __ 3 times the actual
count of 75
Copyright copy by Houghton Mifflin Harcourt 72 All rights reserved
MODULE 10
Ready to Go On
1 The population is the customers in the companyrsquos
computer database The sample is biased because
the customers surveyed are more likely to value their
service
2 number of students who speak 3 or more languages
__________________________________________ size of sample
= total number of students ____________________ size of population
18 ____ 270
= x ______ 30330
18 sdot 337 ____
3 ________
270 sdot 337 ____ 3
= x ______ 30330
2022
______ 30330
= x ______ 30330
x = 2022
About 2022 students speak three or more
languages
3 Two of the random numbers 13 and 167 represent
defective MP3 players
simulated defective players
______________________ size of simulation
= defective players
______________ shipment
2 ___ 10
= x _____ 5000
2 middot 500 _______ 10 middot 500
= x _____ 5000
1000
_____ 5000
= x _____ 5000
x = 1000
Based on the sample about 1000 MP3 players are
defective
4 No the sample is too small compared to the size of
the shipment
5 Sample answer You can make predictions about
populations that are too large to survey
Copyright copy by Houghton Mifflin Harcourt 73 All rights reserved
MODULE 11 Analyzing and Comparing Data
Are You Ready
0875
1 8 ⟌ _
7000
_ -6 400
600
_ -560
40
_ -40
0
0875 875
08
2 5 ⟌ _
40
_ -4 0
0
08 80
025
3 4 ⟌ _
100
_ -80
20
_ -20
0
025 25
03
4 10 ⟌ _
30
_ -3 0
0
03 30
5 4 6 7 7 9 11 15 17
7 + 9
_____ 2 = 8
Median = 8
Mode = 7
6 36 37 40 43 44 49 50 51 56
Median = 44
Mode none
7 9 + 16 + 13 + 14 + 10 + 16 + 17 + 9
________________________________ 8
= 13
Mean = 13
8 108 + 95 + 104 + 96 + 97 + 106 + 94
________________________________ 7 = 100
Mean = 100
LESSON 111
Your Turn
2 Shape dot plots for field hockey players and
softball players have a similar spread
Center center of the field hockey dot plot is less
than the center for softball or basketball players
Spread dot plots for field hockey players and softball
players have a similar spread
3 The median is the middle value Listing the values
in order
1 4 4 4 5 5 5 6 6 6 6 7 7 8 11
In this case median 6 h
range 10 h
The median for internet usage is greater than the
median for exercise and the range is less than the
range for exercise
Guided Practice
1 Class A clustered around two areas
Class B clustered in the middle The dot plots
appear to have about half of the data clustered in
one area
2 Class A two peaks at 4 and 13 mi
Class B looks centered around 7 mi
3 Class A spread from 4 to 14 mi a wide gap with
no data
Class B spread from 3 to 9 mi
4 Class A
4 4 4 4 4 5 5 5 6 6 12 13 13 13 13 14 14
median 6
Class B
3 4 4 4 5 5 5 5 6 6 7 7 7 7 7 8 8 9
median 6
The median for both dot plots is 6 miles
5 Range for class A 14 - 4 = 10 mi
Range for class B 9 - 3 = 6 mi
6 The medians allow you to compare the centers
The ranges allow you to compare the spreads
Independent Practice
7 The dots have a relatively even spread with a peak
at 8 letters
8 The center of the graph is between 6 and 7 letters
9 The dots spread from 3 to 9 letters
10 The mean is the average
3 + 4 + 4 + 5 + 5 + 6 + 7 + 7 + 8 + 8 + 8 + 9
________________________________________ 12
74 ___ 12
asymp 617
Mean asymp 617
3 3 4 5 5 6 7 7 8 8 8 9
Because there are two middle values take their
average
6 + 7
_____ 2 = 13 ___
2 = 65
Median 65
Range 9 - 3 = 6
11 AL clustered in one small interval with an outlier to
the left
VA relatively uniform in height over the same
interval
Copyright copy by Houghton Mifflin Harcourt 74 All rights reserved
12 ALcenteredbetween8and9daysofrainVAcenteredaround10daysofrain
13 ALspreadsfrom1to12daysofrainanoutlierat1VAspreadsfrom8to12daysofrain
14 LynchburgVAhasmoreconsistentlevelsofrainandmorerainpermonthcomparedtoMontgomeryAL
15 GroupAclusteredtotheleftofsize9GroupBclusteredtotherightofsize9
16 OrderedvaluesforgroupA6577757575888888585913Thereare15itemsofdataSince15isoddthereisamiddlenumber8Sothereisnoneedtoaverageanyvalues
MedianforGroupAsize8OrderedvaluesforgroupB859999959595951010105105105115MedianforGroupBsize95
17 GroupArangewithoutlier=13-65=65withoutoutlier=9-65=25GroupBrange=115-85=3
18 SampleanswerGroupAcouldbechildrenandGroupBcouldbeadults
Focus on Higher Order Thinking
19 YesSampleansweronegroupoffivestudentscouldhavethefollowingnumberofpets12345Anothergroupoffivestudentscouldhavethefollowingnumberofpets13335Forbothgroupsofstudentsthemedianwouldbe3andtherangewouldbe4
20RangeanoutliergreatlyincreasestherangewhereasthemedianwillgenerallynotbegreatlyaffectedasitisinthemiddleofallthevaluesAdotplotwillshowboth
LESSON 112
Your Turn
3 SampleanswerTheboxeshavesimilarshapesalthoughGroupBhasashorterboxandshorterwhiskersGroupBrsquosmedianisgreaterthanGroupArsquosGroupBrsquosshorterboxmeansthemiddle50ofitsdataareclosertogetherthanthemiddle50ofGroupArsquos
4 SampleanswerTheshapeissimilartoStoreArsquosThemedianisgreaterthanStoreArsquosandlessthanStoreBrsquosTheinterquartilerangeisaboutthesameasStoreArsquosandlongerthanBrsquos
Guided Practice
1 Minimum72 Maximum88
2 Median79
3 Range88-72=16 IQR85-75=10
4 Themedianheightforhockeyplayersis70inthemedianheightforvolleyballplayersis74Thereforevolleyballplayershavethegreatermedianheight
5 Theminimumheightforhockeyplayersis64intheminimumheightforvolleyballplayersis67inSohockeyplayershavetheshortestplayer
6 IQRforhockeyplayers76-66=10IQRforvolleyballplayers78-68=10BothgroupshaveanIQRof10
7 SampleanswerMinimumandmaximumvaluesmedianrangeandIQRs
Independent Practice
8 CarAhasaminimumof165inandamaximumof210inCarBhasaminimumof160inandamaximumof205inCarAhasamedianof180inCarBhasamedianof185in
9 RangeofCarA210-165=45RangeofCarB205-160=45IQRofCarA195-170=25IQRofCarB200-175=25Bothcarshaverangesof45inandinterquartilerangesof25in
10 CarBhasagreatermediandistancethanCarATheinterquartilerangesarethesamesothemiddle50ofthejumpdistancesforthetwocarshavethesamevariability
11 CarAhaslessvariabilityinthelowestquarterofitsdataandgreatervariabilityinthehighestquarterofitsdataThevariabilityisreversedforCarB
12 CityBhasthelowestpriceof$400andalsohasthehighestpriceof$625
13 MedianforCityA$475MedianforCityB$450Difference475-450=$25CityAhasthehighermedianpriceanditis$25higher
14 SampleanswerCityBabout50ofcarsinCityBleaseforlessthan$450ascomparedtoonly25ofcarsinCityA
15 SampleanswerCityAhasagreatermediancarleasingcostthanCityBCityAhasagreaterIQRofcarleasingcoststhanCityBCityBhasamorepredictablecarleasingcostthanCityAforthemiddle50ofdatavalues
CopyrightcopybyHoughtonMifflinHarcourt 75 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U5M11indd 75 103113 221 AM
Focus on Higher Order Thinking
16 The box plot with the longer box has more variability
in the middle 50 of the values
17 You can identify the minimum and maximum values
and the range of the data You can identify the
quartiles including the lower and upper quartiles
and the median as well as the interquartile range
Together these values help you recognize the
center of the data both the median and the middle
50 It helps you to recognize how spread out the
data are overall and how spread out the middle
50 of the values are around the median A dot
plot contains all the data values which a box plot
does not
18 Sample answer The range tells you very little but
the interquartile range tells you how closely the
middle half of the data cluster around the median
LESSON 113
Your Turn
1 Team 1
Mean
44 + 47 + 67 + 89 + 55 + 76 +85 + 80 + 87 + 69 + 47 + 58 = 804
804 divide 12 = 67
Mean absolute deviation
ǀ 44 - 67 ǀ = 23 ǀ 47 - 67 ǀ = 20
ǀ 67 - 67 ǀ = 0 ǀ 89 - 67 ǀ = 22
ǀ 55 - 67 ǀ = 12 ǀ 76 - 67 ǀ = 9
ǀ 85 - 67 ǀ = 18 ǀ 80 - 67 ǀ = 13
ǀ 87 - 67 ǀ = 20 ǀ 69 - 67 ǀ = 2
ǀ 47 - 67 ǀ = 20 ǀ 58 - 67 ǀ = 11
Mean of absolute values
23 + 20 + 0 + 22 + 12 + 9 +18 + 13 + 20 + 2 + 20 + 11 = 170
170 divide 12 asymp 142
Team 2
Mean
40 + 32 + 52 + 75 + 65 + 70 +72 + 61 + 54 + 43 + 29 + 32 = 625
625 divide 12 asymp 521
Mean absolute deviation
ǀ 40 - 521 ǀ = 121 ǀ 32 - 521 ǀ = 201
ǀ 52 - 521 ǀ = 01 ǀ 75 - 521 ǀ = 229
ǀ 65 - 521 ǀ = 129 ǀ 70 - 521 ǀ = 179
ǀ 72 - 521 ǀ = 199 ǀ 61 - 521 ǀ = 89
ǀ 54 - 521 ǀ = 19 ǀ 43 - 521 ǀ = 91
ǀ 29 - 521 ǀ = 231 ǀ 32 - 521 ǀ = 201
Mean of absolute values
121 + 201 + 01 + 229 +129 + 179 + 199 + 89 +19 + 91 + 231 + 201 = 169
169 divide 12 asymp 141
Difference in means
67 - 521 = 149
149 divide 141 asymp 11
The difference of the means is about 11 times the
MAD
2 There is much more overlap between the two
distributions
Guided Practice
1 Class 1 mean
12 + 1 + 6 + 10 + 1 + 2 + 3 +10 + 3 + 8 + 3 + 9 + 8 + 6 + 8 = 90
90 divide 15 = 6
Class 2 mean
11 + 14 + 11 + 13 + 6 + 7 + 8 + 6 +8 + 13 + 8 + 15 + 13 + 17 + 15 = 165
165 divide 15 = 11
Class 1 mean absolute deviation
ǀ 12 - 6 ǀ = 6 ǀ 1 - 6 ǀ = 5 ǀ 6 - 6 ǀ = 0
ǀ 10 - 6 ǀ = 4 ǀ 1 - 6 ǀ = 5 ǀ 2 minus 6 ǀ = 4
ǀ 3 - 6 ǀ = 3 ǀ 10 - 6 ǀ = 4 ǀ 3 - 6 ǀ = 3
ǀ 8 - 6 ǀ = 2 ǀ 3 - 6 ǀ = 3 ǀ 9 - 6 ǀ = 3
ǀ 8 - 6 ǀ = 2 ǀ 6 - 6 ǀ = 0 ǀ 8 - 6 ǀ = 2
6 + 5 + 0 + 4 + 5 + 4 + 3 + 4 +3 + 2 + 3 + 3 + 2 + 0 + 2 = 46
46 divide 15 asymp 3
Class 2 mean absolute deviation
ǀ 11 - 11 ǀ = 0 ǀ 14 - 11 ǀ = 3 ǀ 11 - 11 ǀ = 0
ǀ 13 - 11 ǀ = 2 ǀ 6 - 11 ǀ = 5 ǀ 7 - 11 ǀ = 4
ǀ 8 - 11 ǀ = 3 ǀ 6 - 11 ǀ = 5 ǀ 8 - 11 ǀ = 3
ǀ 13 - 11 ǀ = 2 ǀ 8 - 11 ǀ = 3 ǀ 15 - 11 ǀ = 4
ǀ 13 - 11 ǀ = 2 ǀ 17 - 11 ǀ = 6 ǀ 15 - 11 ǀ = 2
0 + 3 + 0 + 2 + 5 + 4 + 3 + 5 +3 + 2 + 3 + 4 + 2 + 6 + 2 = 44
44 divide 15 asymp 3
2 Difference in means
11 minus 6 = 5
5 divide 3 asymp 167
3 Sample answer The variation and overlap in the
distributions make it hard to make any convincing
comparison
4 To see how statistical measures vary among the
different samples
Independent Practice
5 23 + 38 + 39 + 48 + 55 + 56 + 71 +86 + 57 + 53 + 43 + 31 = 600
600 divide 12 = 50
ǀ 23 - 50 ǀ = 27 ǀ 38 - 50 ǀ = 12
ǀ 39 - 50 ǀ = 11 ǀ 48 - 50 ǀ = 2
ǀ 55 - 50 ǀ = 5 ǀ 56 - 50 ǀ = 6
ǀ 71 - 50 ǀ = 21 ǀ 86 - 50 ǀ = 36
ǀ 57 - 50 ǀ = 7 ǀ 53 - 50 ǀ = 3
ǀ 43 - 50 ǀ = 7 ǀ 31 - 50 ǀ = 19
27 + 12 + 11 + 2 + 5 + 6 + 21 +36 + 7 + 3 + 7 + 19 = 156
156 divide 12 = 13
The mean is 50degF and the MAD is 13degF
Copyright copy by Houghton Mifflin Harcourt 76 All rights reserved
6 ǀ 23 - 8 ǀ = 15 ǀ 38 - 23 ǀ = 15
ǀ 39 - 24 ǀ = 15 ǀ 48 - 33 ǀ = 15
ǀ 55 - 40 ǀ = 15 ǀ 56 - 41 ǀ = 15
ǀ 71 - 56 ǀ = 15 ǀ 86 - 71 ǀ = 15
ǀ 57 - 42 ǀ = 15 ǀ 53 - 38 ǀ = 15
ǀ 43 - 28 ǀ = 15 ǀ 31 - 16 ǀ = 15
The difference between each average monthly
temperature for City 1 and the corresponding
temperature for City 2 is 15degF
7 50 - 15 = 35
The mean is 35degF and the MAD is 13degF The
mean for City 2 must be 15degF less than the mean
for City 1 and the MAD must be the same
8 50 - 35 = 15
15 divide 13 asymp 12
The difference in the means as a multiple of the
mean absolute deviations is about 12
9
0 4 8 12 16 20 24 28 32 36 40 44
Medians
School B
School A
0 4 8 12 16 20 24 28 32 36 40 44
Means
School B
School A
Both distributions show longer travel times for school
A The distributions of the medians show less
overlap so it is more convincing
10 State A 48 - 38 = 10
10 divide 6 asymp 17
State B 50 - 42 = 8
8 divide 4 = 2
Sample answer The difference in ages is more
significant for State A if you look at the difference in
mean ages but the difference in mean ages is more
significant in State B if you consider variability as
well
11 Smiths Range 70 - 64 = 6
Median 665
Thompsons Range 80 - 74 = 6
Median 77
77 - 665 = 105
105 divide 6 = 175
The difference in the medians is 175 times the
ranges
Focus on Higher Order Thinking
12 Sample answer Jill can reasonably expect the
median of the medians of the samples to be 35
The median of the medians should be close to the
median of the population which should be 35
The outcomes are equally likely
13 Sample answer Ramonrsquos results should produce
more reliable inferences The larger the sample
size the less variability there should be in the
distributions of the medians and means
14 Sample answer Sethrsquos statement is incorrect for any
situation in which the MADs of the population are
not very similar
MODULE 11
Ready to Go On
1 The mean for the start of the school year is given by
5 + 6 + 6 + 7 + 7 + 7 + 7 + 8 + 8 + 8 + 8 + 9 + 9 + 10
________________________________________________ 14
= 105 ____ 14
= 75 mi
The mean for the end of the school year is given by
6 + 6 + 7 + 7 + 8 + 8 + 8 + 8 + 9 + 9 + 9 + 10 + 10 + 10
__________________________________________________ 14
= 115 ___ 14
asymp 82 mi
In summary Start 75 mi End about 82 mi
2 The median is the middle value
List of ordered values for start of school year
5 6 6 7 7 7 7 8 8 8 8 9 9 10
Because there are two middle values take their
average
7 + 8
_____ 2 = 15 ___
2 = 75
Median 75
List of ordered values for end of school year
6 6 7 7 8 8 8 8 9 9 9 10 10 10
Because there are two middle values we would
generally take their average but since they are both
the same and equal to 8
Median 8
Therefore Start 75 mi End 8 mi
3 Range for start of school year 10 - 5 = 5 mi
Range for end of school year 10 - 6 = 4 mi
Therefore Start 5 mi End 4 mi
4 Median for Airplane A 210 in
Median for Airplane B 204 in
Airplane A has a greater median flight length
5 IQR for Airplane A 225 - 208 = 17 in
IQR for Airplane B 230 - 195 = 35 in
Airplane B has a greater interquartile range
Copyright copy by Houghton Mifflin Harcourt 77 All rights reserved
6 The means for the shade plants
7 + 11 + 11 + 12 + 9 + 12 + 8 + 10
______________________________ 8
= 10
The means for the sun plants
21 + 24 + 19 + 19 + 22 + 23 + 24 + 24
__________________________________ 8 = 22
Range of the shade plants 12 - 7 = 5
Range of the sun plants 24 - 19 = 5
Difference in the means 22 - 10 = 12
12 ___ 5
= 24
The difference in the means is 24 times the ranges
7 Sample answer By graphing real-world data you
can identify similarities and differences in related
groups
Copyright copy by Houghton Mifflin Harcourt 78 All rights reserved
MODULE 12 Experimental Probability
Are You Ready
1 6 ___ 10
= 6 divide 2 ______ 10 divide 2
= 3 __ 5
2 9 ___ 15
= 9 divide 3 ______ 15 divide 3
= 3 __ 5
3 16 ___ 24
= 16 divide 8 ______ 24 divide 8
= 2 __ 3
4 9 ___ 36
= 9 divide 9 ______ 36 divide 9
= 1 __ 4
5 45 ___ 54
= 45 divide 9 ______ 54 divide 9
= 5 __ 6
6 30 ___ 42
= 30 divide 6 ______ 42 divide 6
= 5 __ 7
7 36 ___ 60
= 36 divide 12 _______ 60 divide 12
= 3 __ 5
8 14 ___ 42
= 14 divide 14 _______ 42 divide 14
= 1 __ 3
075
9 4 ⟌ _
300
_ -2 80
20
_ -20
0
075
0875
10 8 ⟌ _
7000
_ -6400
600
_ -560
40
_ -40
0
0875
015
11 20 ⟌ _
300
_ -2 00
100
_ -100
0
015
038
12 50 ⟌ _
1900
_ -15 00
4 00
_ -4 00
0
038
13 67 = 67 ____ 100
= 067
14 31 = 31 ____ 100
= 031
15 7 = 7 ____ 100
= 007
16 146 = 100 + 46
= 100 ____ 100
+ 46 ____ 100
= 1 + 046
= 146
17 013 = 13
18 055 = 55
19 008 = 8
20 116 = 116
LESSON 121
Your Turn
3 Because every other number from 1 through 16 is
even choosing an even number is as likely as not
and the probability is 1 __ 2
4 There are 20 possible outcomes when picking a
marble from the jar There are 10 purple marbles
Therefore the probability of picking a purple marble
is 10 ___ 20
or 1 __ 2
5 There are 6 possible outcomes when rolling a cube
There are 2 numbers greater than 4 that can be
rolled 5 and 6 Therefore the probability of rolling a
number greater than 4 is 2 __ 6 or 1 __
3
Solutions KeyProbability
UNIT
6
Copyright copy by Houghton Mifflin Harcourt 79 All rights reserved
7 P(event) + P(complement) = 1
P(5) + P(not 5) = 1
1 __ 8 + P(not 5) = 1
P(not 5) = 7 __ 8
The probability of picking a marble that is not 5 is 7 __ 8
8 P(event) + P(complement) = 1
P(even) + P(odd) = 1
1 __ 2 + P(odd) = 1
P(odd) = 1 __ 2
The probability of rolling an odd number is 1 __ 2
Guided Practice
1 The cards are numbered 1 2 3 4 5 6 7 8 9 10
You pick a number greater than 0 8
You pick an even number 5
You pick a number that is at least 2 7
You pick a number that is at most 0 1
You pick a number divisible by 3 3
You pick a number divisible by 5 2
You pick a prime number 4
You pick a number less than the
greatest prime number 6
2 There are no green playing cards in a standard
deck so randomly picking a green card is
impossible 0
3 There are as many red cards as black cards in a
standard deck so it is as likely as not 1 __ 2
4 All of the numbers are less than 12 so they are also
less than 15 The probability is certain 1
5 There are only two numbers between 1 and 12 that
are divisible by 5 5 and 10 Therefore the probability
is unlikely close to 0
6 There are 5 possible outcomes when spinning the
spinner There are two even numbers 2 and 4
Therefore the probability of the spinner landing on
an even number is 2 __ 5
7 There are 52 possible outcomes when picking a
card from a standard deck There are 13 cards with
diamonds Therefore the probability of picking a
card with a diamond is 13 ___ 52
= 1 __ 4
8 P(event) + P(complement) = 1
P(5) + P(not 5) = 1
1 __ 6 + P(not 5) = 1
P(not 5) = 5 __ 6
The probability of not rolling 5 is 5 __ 6
9 P(event) + P(complement) = 1
P(blue) + P(not blue) = 1
1 __ 3 + P(not blue) = 1
P(not blue) = 2 __ 3
The probability of not landing on blue is 2 __ 3
10 P(event) + P(complement) = 1
P(4) + P(not 4) = 1
1 __ 5 + P(not 4) = 1
P(not 4) = 4 __ 5
The probability of not landing on 4 is 4 __ 5
11 P(event) + P(complement) = 1
P(queen) + P(not queen) = 1
4 ___ 52
+ P(not queen) = 1
P(not blue) = 48 ___ 52
= 12 ___ 13
The probability of not picking a queen is 12 ___ 13
12 Sample answer pulling a red marble out of a bag
that contains only blue marbles pulling a white
marble out of a bag that contains only white marbles
Independent Practice
13 There are 52 possible outcomes when picking from
a standard deck of cards There are 8 cards that
have an ace or a king Therefore the probability of
selecting
an ace or a king is 8 ___ 52
or 2 ___ 13
14 P(event) + P(complement) = 1
P(apple or peach) + P(not apple or peach) = 1
9 ___ 12
+ P(not apple or peach) = 1
P(not apple or peach) = 3 ___ 12
or 1 __ 4
Therefore the probability of picking a piece of fruit
that is not an apple or a peach is 3 ___ 12
or 1 __ 4
15 No it is unlikely that she will have oatmeal for
breakfast Since there are 4 choices the probability
that she will choose oatmeal is 1 __ 4 or 25
16 Purple There are a lot more plants with purple
flowers than with white flowers The probability of
selecting a white-flowered plant is 2 __ 9 while the
probability of selecting a purple-flowered plant is 7 __ 9
17 Because she has more colored T-shirts than white
T-shirts it is likely that she will pick a colored T-shirt
She has 14 total T-shirts and 10 of the shirts are
colored Therefore the probability she will choose a
colored T-shirt is 10 ___ 14
or 5 __ 7
18 1 None of the students in the class have red hair so
it is certain that a randomly chosen student will not
have red hair
Copyright copy by Houghton Mifflin Harcourt 80 All rights reserved
19 a There are 14 total coins and 8 blue coins so the
probability that the coin is blue is 8 ___ 14
or 4 __ 7
b Removing 1 of the 8 blue coins leaves 7 blue
coins Adding 3 more to the 6 red coins makes
9 red coins The total of coins in the bag is now
16 Therefore the probability of choosing a red
coin is 9 ___ 16
c Removing 1 of the 6 red coins leaves 5 red coins
Adding 3 to the 8 blue coins makes 11 blue coins
The total of coins in the bag is now 16 Therefore
the probability of choosing a red coin is 5 ___ 16
Focus on Higher Order Thinking
20 Sample answer If some marbles in a jar are heavier
than others then the heavier marbles would sink
and be less likely to be selected
21 Yes Because there are only two colors selecting
not black is equal to selecting red So
P(not black) + P(black) =P(not black) + P(not red) = 1
22 2 is the number of ways the event can happen 7 is
the number of outcomes in the sample space
landing on blue
LESSON 122
Your Turn
7 The total number of spins is 6 + 14 + 10 = 30
Red 10 ___ 30
= 1 __ 3
Yellow 14 ___ 30
= 7 ___ 15
Blue 6 ___ 30
= 1 __ 5
8 Sample answer Let 1 and 2 represent blue 3 and 4
represent white and 5 and 6 represent blue Toss
the cube 50 times to determine the experimental
probability for each color Predict the next ball will be
the color with the greatest experimental probability
Guided Practice
1 The total number of spins is 14 + 7 + 11 + 8 = 40
A 14 ___ 40
= 7 ___ 20
= 035 = 35
B 7 ___ 40
= 0175 = 175
C 11 ___ 40
= 0275 = 275
D 8 ___ 40
= 1 __ 5 = 020 = 20
2 Sample answer Write ldquoyesrdquo on 6 cards and ldquonordquo on
4 cards Draw a card at random 50 times Use the
number of ldquoyesrdquo cards drawn as the prediction
3 Use an experiment to find the number of times the
event occurs for a certain number of trials
Independent Practice
4 6 ___ 10
or 3 __ 5 It is reasonable to assume that Dreersquos
past performance is an indicator of her future
performance There is no way to accurately
represent 3 __ 5 on a number cube with 6 faces
5 Sample answer Compare the number of wins to the
total number of trials
number of wins _________________ total number of trials
= 8 ___ 48
= 1 __ 6
6 There are 20 possible outcomes when picking a
name Ryan is 1 person Therefore the probability
he is chosen is 1 ___ 20
and the probability he is not
chosen is 19 ___ 20
P(Ryan) + P(not Ryan) = 1
1 ___ 20
+ P(not Ryan) = 1
P(not Ryan) = 19 ___ 20
7 Yes because it is based on actual data of weather
patterns
8 Joan Mica hit the ball 8 ___ 48
times or about 17 of her
times at bat Meanwhile Joan hit the ball 12 ___ 40
times
or 30 of her times at bat Therefore Joan has the
greater experimental probability and is more likely to
get a hit next time
9 Gabbyrsquos experimental probability of hitting an ace
is 4 ___ 10
or 2 __ 5 Gabby could serve 16 aces in her next
40 serves because 2 __ 5 of 40 is 16
10 The experimental probability her dog wonrsquot want to
go outside is 5 ___ 12
or about 417
P(outside) + P(not outside) = 1
7 ___ 12
+ P(not outside) = 1
P(not outside) = 5 ___ 12
or 417
Focus on Higher Order Thinking
11 She did not add 40 and 60 to find the total number
of trials P(heads) = 40 ____ 100
12 Sample answer coin toss Heads represents male
and tails represents female Toss the coin 50 times
and use the results to make a prediction
13 Sample answer Make an index card to represent
each coin then pick one card at random No since
the coins are different sizes they do not each have
the same probability of getting pulled out of my
Copyright copy by Houghton Mifflin Harcourt 81 All rights reserved
LESSON 123
Your Turn
1 P(coffee + small) = number of coffee + small
_____________________ total number of orders
= 60 ____ 400
= 3 ___ 20
= 15
3 P(goId + 20 in) = number of gold + 20 in
_________________________ total number of necklaces sold
= 12 ___ 75
or 4 ___ 25
Guided Practice
1 P(female + age 22ndash39)
= number of female + age 22ndash39
__________________________ total number of patients
= 50 ____ 400
or 1 __ 8
2 Sample answer There are six possible outcomes
standard with vacuum standard with no vacuum
deluxe with vacuum deluxe with no vacuum
superior with vacuum and superior with no vacuum
Students could write the outcomes on six index
cards and put them in a box Then they can draw a
card 50 times record the results and find the
experimental probability that a customer chooses a
deluxe wash with no vacuum by dividing the
frequency of this compound event by 50 the total
number of trials
3 Find the number of occurrences of the compound
event and divide it by the total number of trials
Independent Practice
4 Divide the number of 2 piece + salad orders 33 by
the total number of orders 330
P = number of 2 piece + salad
______________________ total number of orders
= 33 ____ 330
= 1 ___ 10
5 P = number of red notebooks + 150 pages
_______________________________ total number of notebooks sold
= 60 ____ 400
= 3 ___ 20
6 P(red notebook) = number of red notebooks _____________________ total number of notebooks
= 55 + 60 + 23
____________ 400
= 138 ____ 400
= 69 ____ 200
7 12 the total is the product of 3 page-count choices
and 4 color choices
8 She left out the 53 students that read 150 pages
P(7th grade + 100 pages) = 85 ____ 250
= 17 ___ 50
9 Sample answer 8th grade the results table
suggests 8th grade students are the least likely to
have read 150 pages compared to students in 6th or
7th grade
Focus on Higher Order Thinking
10 Greater heads occurs on about half the occasions
that you roll a 6 so the compound event is half as
likely
11 Sample answer For 2 outcomes he could use even
and odd numbers For 3 outcomes he could use
1 or 2 3 or 4 and 5 or 6 For 6 outcomes he could
use each number once
12 P(male + open toe) = 11 ____ 300
P(male has open toe) = 11 ____ 150
No the first scenario
includes females and the second does not
13 No because coins are fair and the probabilities do
not appear to be equally likely
14 Sample answer On a coin heads = male and
tails = female On a number cube (1 or 2) = 6th
grade (3 or 4) = 7th grade and (5 or 6) = 8th
grade Toss the coin and roll the number cube 50
times each Record the number of outcomes that are
heads and 3 or 4
LESSON 124
Your Turn
1 024 times 550 =132 customers
2 No About 371 of the emails out of 12372 will come
back undelivered because 003 times 12372 asymp 371 The
editorrsquos prediction is too high
3 024 times 350 = 84 customers Yes because 107
customers buying two or more pairs would be more
than only 84 customers
Guided Practice
1 030 times 50 = 15 times
2 015 times 365 asymp 55 days
3 No about 1009 of the candles out of 16824 will be
returned because 006 times 16824 asymp 1009
A prediction of 812 is too low
4 No about 746 toys out of 24850 will be defective
because 003 times 24850 asymp 746 A prediction of 872 is
too high
5 98 ____ 100
= x ___ 40
= 39 ___ 40
or 39 times
No if she were late 6 out of 40 times the rate of
being on time would be only 85 in which case the
light-railrsquos claim of 98 is too high
6 18 ____ 100
= x _____ 5000
= 900 _____ 5000
or 900 students Yes the
collegersquos claim is close to the number actually
accepted
times04
times04
times50
times50
Copyright copy by Houghton Mifflin Harcourt 82 All rights reserved
7 Solve a proportion using the experimental probability
to find an expected number of events to happen
Make a prediction based on the expected number of
events
Independent Practice
8 4 ____ 100
= x ____ 200
= 8 ____ 200
or 8 students More students
moved than expected because 12 is more than 8
9 Yes 6th grade 2 ____ 100
= x ____ 250
= 5 ____ 250
or 5 students
7th grade 4 ____ 100
= x ____ 200
= 8 ____ 200
or 8 students
8th grade 8 ____ 100
= x ____ 150
= 12 ____ 150
or 12 students
Since 5 + 8 + 12 = 25 the values in the table
support his claim of 30 students
10 6 ____ 100
= x ____ 300
= 18 ____ 300
or 18 seats If an airplane is
overbooked with 310 passengers only 291 are
expected to show up since 310 times 94 asymp 291
11 006 times 600 = 36 clients If 40 clients did not pay it
would be slightly more than average
12 080 times 20 = 16 team members The coachrsquos claim is
not accurate because the average number of
students at practice is 144 ____ 8 = 8
13 He set up the fraction incorrectly it should be
1 ___ 30
= x ____ 180
Focus on Higher Order Thinking
14 1 __ 2 of 12 = 6 normal rejection rate
500 times 6 = 30 transactions rejected by a
normal gas pump
15 098 times 15000 = 14700 on-time flights Sample
answer No one week of data could be misleading
and not representative of the yearly on-time prob-
ability (because it ignores bad weather etc)
16 Sample answer No They could expect to get 96
responses with the old letter since
4 ____ 100
= x _____ 2400
= 96 _____ 2400
or 96 letters Therefore the
new letter received fewer responses
MODULE 12
Ready to Go On
1 H1 H2 T1 T2
2 6 ___ 10
= 3 __ 5
3 13 ___ 20
4 3 of the 7 total trials resulted in a sum more than 5
Therefore the experimental probability is 3 __ 7
5 I would predict he would reach first base 24 times
because 3 ___ 10
= x ___ 80
= 24 ___ 80
or 24 times
6 You can use the experimental probability based on
observation or simulation to set up a proportion and
use the proportion to predict a value
times15
times15
times24
times24
times2
times2
times3
times3
times2
times2
times25
times25
times8
times8
Copyright copy by Houghton Mifflin Harcourt 83 All rights reserved
MODULE 13 Theoretical Probability and
Simulations
Are You Ready
075
1 4 ⟌ _
300
_ -2 80
20
_ -20
0
075 = 75
04
2 5 ⟌ _
20
_ -2 0
0
04 = 40
09
3 10 ⟌ _
90
_ -9 0
0
09 = 90
035
4 20 ⟌ _
700
_ -6 00
1 00
_ -1 00
0
035 = 35
0875
5 8 ⟌ _
7000
_ thinsp-6 400
600
_ -560
40
_ -40
0
0875 = 875
005
6 20 ⟌ _
100
_ -1 00
0
005 = 5
076
7 25 ⟌ _
1900
_ -17 50
1 50
_ -1 50
0
076 = 76
046
8 50 ⟌ _
2300
_ -20 50
3 00
_ -3 00
0
046 = 46
9 1 - 1 __ 5 = 5 __
5 - 1 __
5
= 4 __ 5
10 1 - 2 __ 9 = 9 __
9 - 2 __
9
= 7 __ 9
11 1 - 8 ___ 13
= 13 ___ 13
- 8 ___ 13
= 5 ___ 13
12 1 - 3 ___ 20
= 20 ___ 20
- 3 ___ 20
= 17 ___ 20
13 8 ___ 15
times 5 __ 8 =
18 ___ 315
times 5 1 ___
8 1
= 1 __ 3
14 2 __ 9 times 3 __
4 =
12 __ 39
times 3 1 ___
4 2
= 1 __ 6
15 9 ___ 16
times 12 ___ 13
= 9 ___ 416
times 12 3 _____
13
= 27 ___ 52
16 7 ___ 10
times 5 ___ 28
= 17 ___
210 times 5
1 ____
28 4
= 1 __ 8
LESSON 131
Your Turn
2 The probability of an event is the ratio of the number
of ways the event can occur to the total number of
equally likely outcomes Therefore
P(rolling a 3 or 4) =
number of sides with 3 or 4 ________________________ total number of sides on cube
= 2 __ 6 = 1 __
3
3 The total number of outcomes in the sample space
is the denominator of the formula for theoretical
probability
Copyright copy by Houghton Mifflin Harcourt 84 All rights reserved
Guided Practice
1
Basket A Basket B
Total number of outcomes5 + 3 + 8
= 16
7 + 4 + 9
= 20
Number of red balls 3 4
P(win) =
Number of red balls
_____________________ Total number of outcomes
3 ___
16 4 ___
20 = 1 __
5
2 To compare the two probabilities of 1 __ 5 and 3 ___
16 use
the least common denominator of 80
1 __ 5 = 16 ___
80
3 ___ 16
= 15 ___ 80
Therefore 16 ___ 80
gt 15 ___ 80
so 1 __ 5 gt 3 ___
16
Choosing Basket B gives you a better chance of
winning
3 There are a total of 6 odd sections The total number
of sections (odd and even) is 11
P(odd) = number of odd sections ____________________ total number of sections
= 6 ___ 11
4 There are a total of 5 even sections The total
number of sections (odd and even) is 11
P(even) = number of even sections ____________________ total number of sections
= 5 ___ 11
5 The total number faces on a number cube is 6 and
rolling either a 3 or 4 is equal to 2 possibilities
P(rolling a 3 or 4) = number of sides with 3 or 4 ________________________ total number of sides on cube
= 2 __ 6 = 1 __
3
6 Sample answer No but it might be reasonably
close
7 Divide the number of ways the event can occur
by 20
Independent Practice
8 P(yellow) = number of yellow sections
_____________________ total number of sections
= 2 __ 6
= 1 __ 3 033 or 33
9 P(blue or green) = number of blue or green sections
___________________________ total number of sections
= 8 ___ 12
= 2 __ 3 067 or 67
10 P(cherry) = number of cherry cough drops
_________________________ total number of cough drops
= 4 ___ 14
= 2 __ 7 029 or 29
11 P(black card) = number of black cards __________________ total number of cards
= 26 ___ 52
= 1 __ 2 050 or 50
12 P(lime) = number of limes ________________________ total number of pieces of fruit
= 12 - 5 ______ 12
= 7 ___ 12
058 or 58
13 There are a total of 20 DVDs There are 12 DVDs
that are not comedies (5 science fiction plus
7 adventure)
P(not a comedy)
= number of DVDs which are not comedies _________________________________ total number of DVDs
= 5 + 7 _________
5 + 7 + 8 = 12 ___
20
= 3 __ 5 060 or 60
14 There are a total of 6 faces on a number cube There
are 2 faces (3 and 4) that are greater than 2 and
less than 5 which means 2 possibilities
P(greater than 2 and less than 5)
= number of sides with 3 and 4 ________________________ total number of sides on cube
= 2 __ 6
= 1 __ 3 033 or 33
15 9 represents the ways the event can occur
13 represents the number of equally likely outcomes
16 There are a total 16 coins and there are 6 coins that
are greater than 5 cents Therefore
P(coin worth more than 5 cents)
= number of coins worth more than 5 cents _________________________________ total number of coins
= 6 ___ 16
or 3 __ 8
The event is choosing a dime or a quarter and 6 of
the 16 coins are dimes or quarters
Focus on Higher Order Thinking
17 Sample answer Riley divided the number of petunia
seeds by the number of begonia seeds rather than
the total number of seeds The correct probability is
5 ______ 5 + 15
= 5 ___ 20
= 1 __ 4
times16
times16
times5
times5
Copyright copy by Houghton Mifflin Harcourt 85 All rights reserved
18 a The total number of students in the club is 35
There are 20 seventh graders Therefore
P(seventh grader) =
number of seventh graders
______________________ total number of students
= 20 ___ 35
= 4 __ 7
There are 15 eighth graders in the club Therefore
P(eighth grader) =
number of eighth graders
_____________________ total number of students
= 15 ___ 35
= 3 __ 7
Because 4 __ 7 gt 3 __
7 choosing a seventh grader is
more likely
b No each student has the same probability of
being selected 1 ___ 35
19 Sample answer The number of trials is twice the
number of marbles in the jar If the probabilities for
each color were the same the number of times that
color was drawn would be twice the number of
marbles with that color in the jar
20 Red The theoretical probability of choosing red is
P(red) = number of red marbles ___________________ total number of marbles
= 8 ___ 20
The experimental probability of choosing red is
14 ___ 40
or 7 ___ 20
Therefore the difference in the theoretical probability
and experimental probability of choosing a red
marble is 8 ___ 20
- 7 ___ 20
= 1 ___ 20
For blue the theoretical probability is
P(blue) = number of blue marbles ____________________ total number of marbles
= 10 ___ 20
The experimental probability is 16 ___ 40
= 8 ___ 20
Therefore the difference in the theoretical probability
and experimental probability of choosing a blue
marble is 10 ___ 20
- 8 ___ 20
= 2 ___ 20
= 1 ___ 10
For yellow the theoretical probability is
P(yellow) = number of yellow marbles
_____________________ total number of marbles
= 2 ___ 20
The experimental probability is 10 ___ 40
= 5 ___ 20
Therefore the difference in the theoretical probability
and experimental probability of choosing a yellow
marble is 5 ___ 20
- 2 ___ 20
= 3 ___ 20
Choosing a red marble has the smallest difference
between theoretical and experimental probability
LESSON 132
Your Turn
3 P(ham sandwich) =
number of combinations containing ham
_________________________________ total number of sandwich combinations
= 4 ___ 12
= 1 __ 3
4 P(sandwich containing Swiss cheese) =
number of combinations containing Swiss
__________________________________ total number of sandwich combinations
= 6 ___ 12
= 1 __ 2
5 To find the sample space make lists of possible
codes First make a list of codes that start with 0
and have 0 as the second digit
0 0 0 0
0 0 0 1
0 0 1 0
0 0 1 1
List of codes that start with 0 and have 1 as the
second digit
0 1 0 0
0 1 0 1
0 1 1 0
0 1 1 1
List of codes that start with 1 and have 0 as the
second digit
1 0 0 0
1 0 0 1
1 0 1 0
1 0 1 1
List of codes that start with 1 and have 1 as the
second digit
1 1 0 0
1 1 0 1
1 1 1 0
1 1 1 1
In total the number of possible outcomes is 16
There are six codes with exactly two 0s
0 0 1 1
0 1 0 1
0 1 1 0
1 0 0 1
1 0 1 0
1 1 0 0
This means the number of outcomes for a code with
exactly two 0s is 6 Therefore
P(Code exactly two 0s)
= number of favorable outcomes ____________________________ total number of possible outcomes
= 6 ___ 16
= 3 __ 8
Copyright copy by Houghton Mifflin Harcourt 86 All rights reserved
Guided Practice
1
1 2 3 4 5 6
11 sdot 1
= 1
1 sdot 2
= 2
1 sdot 3
= 3
1 sdot 4
= 4
1 sdot 5
= 5
1 sdot 6
= 6
22 sdot 1
= 2
2 sdot 2
= 4
2 sdot 3
= 6
2 sdot 4
= 8
2 sdot 5
= 10
2 sdot 6
= 12
33 sdot 1
= 3
3 sdot 2
= 6
3 sdot 3
= 9
3 sdot 4
= 12
3 sdot 5
= 15
3 sdot 6
= 18
44 sdot 1
= 4
4 sdot 2
= 8
4 sdot 3
= 12
4 sdot 4
= 16
4 sdot 5
= 20
4 sdot 6
= 24
55 sdot 1
= 5
5 sdot 2
= 10
5 sdot 3
= 15
5 sdot 4
= 20
5 sdot 5
= 25
5 sdot 6
= 30
66 sdot 1
= 6
6 sdot 2
= 12
6 sdot 3
= 18
6 sdot 4
= 24
6 sdot 5
= 30
6 sdot 6
= 36
2 There are 15 entries in the table that are multiples
of 4 The total number of entries in the table is 36
P(multiple of 4) = number of multiples of 4
_________________________ total number of entries in table
= 15 ___ 36
3 There are 23 entries in the table that are less than
13 The total number of entries is 36
P(less than 13) = number of entries less than 13 _________________________ total number of entries in table
= 23 ___ 36
4 H
HHH HHT
H
H
Coin 1
List
Coin 2
Coin 3 T
T
HTH HTT
H T
T
H
H T
THH THT
T
H T
TTH TTT
Coin 1
List
Coin 2
Coin 3
5 Count the total number of outcomes in the list 8
6 The only way to get three tails is TTT
7 P = number of outcomes with 3 tails __________________________ total number of outcomes
= 1 __ 8
8 There are 3 way(s) to obtain exactly two heads
HHT HTH THH
P = number of outcomes with exactly 2 heads
__________________________________ total number of possible outcomes
= 3 __ 8
9 You need to know the number of equally likely
outcomes in the sample space
Independent Practice
10
Checkered
Red
Checkered
Red
Blue
Black
Checkered
Red
Checkered
Red
Blue
Black
Checkered
Red
Checkered
Red
Blue
Black
Shirt Pants Shoes
Yellow
Red
Green
11 There are 6 combinations that include red shoes
The total number of combinations is 12 Therefore
P(red shoes) = number of combinations with red shoes ________________________________ total number of combinations
= 6 ___ 12
= 1 __ 2
12 There are four combinations that do not include red
Shirt Pants Shoes
Green Blue Checkered
Green Black Checkered
Yellow Blue Checkered
Yellow Black Checkered
P(no red) = number of outfits with no red _______________________ total number of outfits
= 4 ___ 12
= 1 __ 3
13 Let the other three band members be A B and C
The list of possible combinations is
Rhee Pamela
Rhee A
Rhee B
Rhee C
Pamela A
Pamela B
Pamela C
A B
A C
B C
There is a total of 10 combinations Of these only 1
has Rhee and Pamela so
P(Rhee and Pamela)
= Rhee and Pamela ________________________ total number of combinations
= 1 ___ 10
Copyright copy by Houghton Mifflin Harcourt 87 All rights reserved
14 The sample space can be found from adding all
possible combinations of the two numbers
1 2 3 4 5 6
11 + 1
= 2
1 + 2
= 3
1 + 3
= 4
1 + 4
= 5
1 + 5
= 6
1 + 6
= 7
22 + 1
= 3
2 + 2
= 4
2 + 3
= 5
2 + 4
= 6
2 + 5
= 7
2 + 6
= 8
33 + 1
= 4
3 + 2
= 5
3 + 3
= 6
3 + 4
= 7
3 + 5
= 8
3 + 6
= 9
44 + 1
= 5
4 + 2
= 6
4 + 3
= 7
4 + 4
= 8
4 + 5
= 9
4 + 6
= 10
55 + 1
= 6
5 + 2
= 7
5 + 3
= 8
5 + 4
= 9
5 + 5
= 10
5 + 6
= 11
66 + 1
= 7
6 + 2
= 8
6 + 3
= 9
6 + 4
= 10
6 + 5
= 11
6 + 6
= 12
There is a total of 36 possible sums Of these there
are 10 less than 6
P(sum is less than 6)
= number of sums less than 6 ____________________________ total number of possible outcomes
= 10 ___ 36
= 5 ___ 18
15 The sample space can be found from a tree
diagram
Khakis
Shorts
Shirt Pants Shoes
Collared Jeans
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Khakis
Shorts
T-shirt Jeans
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Total number of possible outcomes is 18 the
number of combinations which include jeans but
not sneakers is 4 Therefore
P(jeans but not sneakers)
= number of outfits with jeans no sneakers
_________________________________ total number of possible outcomes
= 4 ___ 18
= 2 __ 9
16 For each chair lift there are 6 possible trails So you
can multiply the number of choices of chair lifts (3)
by the number of trails (6)
17 Because there are 3 choices for the first item and
2 for the second there are 3 middot 2 = 6 possible
outcomes
18 There is a total of 30 possible shoe sizes Of these
the number of red shoes size 9 or larger is 7
Therefore
P(red and size 9 or larger) =
number of red shoes size 9 or larger
______________________________ total number of possible outcomes
= 7 ___ 30
Focus on Higher Order Thinking
19 Sondra orders one item from each column There
are 4 main dishes 4 vegetables and two sides so
the sample space is 4 sdot 4 sdot 2 = 32 The possible
outcomes of Sondrarsquos order are shown in the tree
diagram
Carrots
Sweet potato
Pasta
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Carrots
Sweet potato
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Carrots
Sweet potato
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Carrots
Sweet potato
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Salmon
Beef
Pork
Copyright copy by Houghton Mifflin Harcourt 88 All rights reserved
There are 8 total number of outcomes that include
salmon Therefore
Sondra P(salmon) = 8 ___ 32
= 1 __ 4
Gretchen orders a main dish and a vegetable There
are 4 main dishes and 4 vegetables so the sample
space is 4 sdot 4 = 16 The possible outcomes of
Gretchenrsquos order are shown in the tree diagram
Carrots
Sweet potato
PastaPeas
Asparagus
Carrots
Sweet potato
Peas
Asparagus
Carrots
Sweet potato
Peas
Asparagus
Carrots
Sweet potato
Peas
Asparagus
Salmon
Beef
Pork
There are 4 total number of outcomes that include
salmon Therefore
Gretchen (salmon) = 4 ___ 16
= 1 __ 4
Because the probabilities for Sondra and Gretchen
are equal neither has a greater probability of getting
a meal that includes salmon
20 a For possible two-digit codes consider first codes
that begin with 1 12 13 14 15 There are a total
of 4 possible codes This pattern continues for
each of the 5 digits and therefore we have a total
of 4 + 4 + 4 + 4 + 4 = 20 possible two-digit
codes (four codes each that begin with each of
the numbers 1ndash5)
For possible three-digit codes there are 12
possible codes that begin with 1 and so there are
12 possible codes for each of the numbers 1ndash5
making a total of 5 sdot 12 = 60 possible three-digit
codes
We can predict the number of possible five-digit
codes because we know there are 60 possible
three-digit codes and for each of these there are
only two digits that can be added to the end of
each code to make them five-digit codes These
are the digits that were not used in the three-digit
code and they have two possible orders for a
total of 60 sdot 2 = 120 possible five-digit codes
As a concrete example again consider the three-
digit codes that begin with 1 Tacking on the digits
which are not included in these three-digit codes
in both orders we have 12345 12354 12435
12453 12534 12543 13245 13254 13425
13452 13524 13542 14235 14253 14325
14352 14523 14532 15234 15243 15324
15342 15423 15432 If we do the same for the
three-digit codes beginning with 2ndash5 we will find
the 120 possible five-digit codes
b Now that the numbers can repeat for two-digit
codes take the 20 codes from before and add five
more codes (11 22 33 44 55) which makes a
total of 25 two-digit codes
For three-digit codes take the 60 codes from
before and add the 5 codes that have all digits
the same plus codes which have two digits
which are repeats To find these consider first the
codes with the first two digits the same 112 113
114 115 221 223 224 225 331 332 334 335
441 442 443 445 551 552 553 554 There
are 20 possible codes There are also 20 possible
codes with the last two digits the same Finally
consider the codes where the first and last digits
are the same For the repeated digit 1 we have
121 131 141 151 or 4 possible codes For each
of the digits 1ndash5 we have 4 possible codes for a
total of 4 sdot 5 = 20 Therefore the overall total
60 + 5 + 20 + 20 + 2 = 125 three-digit codes
To solve for how many possible 5 digit codes
there are notice a pattern in the codes For
two-digit codes the total possible codes is the
number of possible digits raised to the power
equal to the number of digits in the code or
52 = 25 For three-digit codes the number of
possible digits is the same and the number
of digits in the code is 3 so we have 53 = 125
Following this pattern there are 55 = 3125
possible five-digit codes
c Sample answer The better choice is to have the
digits repeat there are more unique codes with
repeated digits than without so it would be more
difficult for someone to guess a code for a locker
LESSON 133
Your Turn
1 There are 4 numbers less than 5 on a standard
number cube There are 6 possible outcomes so
P(number less than 5) = 4 __ 6 = 2 __
3
The number of events is 250 Therefore
P(number less than 5) times Number of events =
2 __ 3 times 250 = 16666 or about 167 times
Copyright copy by Houghton Mifflin Harcourt 89 All rights reserved
2 Set up a proportion The probability of getting
heads is 1 __ 2
1 __ 2 = x ___
18
1 __ 2 = x ___
18
x = 9
about 9 times
3 There are 17 total marbles and 8 are red Therefore
P(red) = 8 ___ 17
P(not red) = 1 - 8 ___ 17
= 9 ___ 17
It is more likely that he picks a marble that is not red
4 No Sample answer There is a total of 71 bills in the
bag and there are 11 bills worth $6 or more
Therefore
P(bill worth $6 or more) = 11 ___ 71
This is about a 15 probability so it is not likely you
will win enough to pay for your ticket
Guided Practice
1 An equally likely chance means that the probabilities
of being assigned to each crew are the same and
since there are three possibilities each has a
probability of 1 __ 3
Apartment 1 __ 3 Condo 1 __
3 House 1 __
3
The probability of being assigned to house crew is 1 __ 3
Set up and solve a proportion
1 __ 3 = x ___
18
1 __ 3 = x ___
18
x = 6
This means that Bob can expect to be assigned to
the house crew about 6 times out of 18
2 Since half of the ticket holders will receive a prize
this means that 300 divide 2 = 150 people will receive a
prize Because they are equally likely to receive one
of three prizes the probability of winning each of the
prizes is 1 __ 3 so the probability of winning a movie
ticket is 1 __ 3 The number of events is 150 Therefore
P(movie ticket) times Number of events = 1 __ 3 times 150 =
50 or 50 people are predicted to win a movie ticket
3 The total number of students in Mr Jawaranirsquos class
is 28 The probabilities of picking a student at
random with a certain eye color are
P(hazel) = 9 ___ 28
P(brown) = 10 ___ 28
P(blue) = 7 ___ 28
P(green) = 2 ___ 28
The event with the greatest probability is choosing a
person with brown eyes
4 You can find and compare probabilities Or you can
use probability to set up and solve a proportion or
an equation that relates the probability to the
unknown quantity
Independent Practice
5 The total number of marbles in the bag is 9 The
number of white or gray marbles is 3 Therefore
P(white or gray) = 3 __ 9 = 1 __
3
The number of events is 45 The equation to make a
prediction is then
P(white or gray) times Number of events = 1 __ 3 times 45 = 15
You can expect to get 15 white or gray marbles
6 A spinner which has an equal likelihood to land on
green or yellow means that the number of green and
yellow sections must be equal More likely to land on
red means that there must be more red sections
than yellow or green A Sample answer is
Y GRR
R R
RR
7 Because half the deck is red the probability of
drawing a red card is 1 __ 2 Because there are three
face cards for each of four suits there are 3 sdot 4 = 12
face cards and the probability of drawing a face
card is 12 ___ 52
To compare 1 __ 2 and 12 ___
52 use the least
common denominator of 52 so that 1 __ 2 = 26 ___
52 Given
that 12 ___ 52
lt 26 ___ 52
the probability of drawing a red card
is higher than of drawing a face card and it is more
likely that Dawn draws 2 red cards
8 The total number of aces in a deck is 4 Therefore
P(ace) = 4 ___ 52
= 1 ___ 13
The number of events is 39 The equation to make a
prediction is then
P(ace) middot Number of events = 1 ___ 13
times 39 = 3
He is predicted to draw an ace 3 times
9 The total number of red cards is 26 Therefore
P(red card) = 26 ___ 52
= 1 __ 2
The number of events is 1000 The equation to
make a prediction is then
P(red card) sdot Number of events = 1 __ 2 sdot 1000 = 500
The player is predicted to turn over a red card as the
first card 500 times
10 The sample space can be found from adding all
possible combinations of the two numbers
times6
times6
times9
times9
Copyright copy by Houghton Mifflin Harcourt 90 All rights reserved
1 2 3 4 5 6
1 2 3 4 5 6 7
2 3 4 5 6 7 8
3 4 5 6 7 8 9
4 5 6 7 8 9 10
5 6 7 8 9 10 11
6 7 8 9 10 11 12
There is a total of 36 possible sums Of these there
are 5 ways to roll a sum of 8 and 2 ways to roll a
sum of 11 The probabilities are
P(sum of 8) = 5 ___ 36
P(sum of 11) = 2 ___ 36
Because the probability of rolling a sum of 8 is
greater than that of rolling a sum of 11 ( 5 ___ 36
gt 2 ___ 36
) John is more likely to win
11 There are 5 possible numbers greater than 15 so
P(greater than 15) = 5 ___ 20
= 1 __ 4
The number of events is 180 The equation to make
a prediction is then
P(greater than 15) times Number of events =
1 __ 4 times 180 = 45
The chosen number will be greater than 15 for 45
days in the school year
12 The sample space for a standard cube is 36 and
there are 3 combinations that will have a sum of 4
so P(sum of 3) = 3 ___ 36
= 1 ___ 12
The number of events is 36 The equation to make a
prediction is then
P(sum of 3) times Number of events = 1 ___ 12
middot 36 = 3
Eben is predicted to roll a sum of 4 a total of 3 times
13 Sample answer No Every time you flip a coin the
probability of heads is 1 __ 2 but in reality you could flip
a coin many times and have it land heads up every
time
14 Sample answer A bag of marbles contains red and
blue marbles that are different sizes Since it is easy
to feel the difference between the two colors all of
the outcomes are not equally likely You cannot make
a prediction using theoretical probability
Focus on Higher Order Thinking
15 Sample answer What is the theoretical probability
that the coin lands on heads and you pick a marble
that is not green
The probability that the coin lands on heads is 1 __ 2
and the probability that the picked marble is not
green is 3 + 9 _________
3 + 8 + 9 = 12 ___
20 The product of these two
probabilities is 1 __ 2 times 12 ___
20 = 12 ___
40
16 Sample answer It is much more likely that he rolls a
5 or the coin lands on heads
The probability that Horace rolls a 5 and the coin
lands on heads is given by
P(5 and heads) = 1 __ 2 times 1 __
6 = 1 ___
12
In the case where Horace rolls a 5 or the coin lands
on heads the probability is given by
P(5 or heads) = 1 __ 6 + 1 __
2 - 1 __
6 times 1 __
2 = 7 ___
12
17 Yes but only theoretically because in reality nothing
can occur 05 times Sample answer The probability
that a flipped coin lands heads up is 1 __ 2 so in 75 flips
you can expect heads about 75 ___ 2 or 375 times
LESSON 134
Your Turn
1 Sample answer (data and percent will vary)
Trial Numbers generated 3 Males first
1 0 0 1 No
2 0 1 No
3 1 No
4 0 1 No
5 1 No
6 0 0 0 1 Yes
7 0 0 1 No
8 0 1 No
9 1 No
10 0 0 0 0 1 Yes
For these data the experimental probability that the
elephant gives birth to 3 male calves before having a
female calf is 2 ___ 10
or 20
2 Sample Answer (data and percent will vary)
Trial Numbers generated Correct answers
1 1 0 1 1 0 3
2 0 1 0 0 1 2
3 0 0 0 0 1 1
4 0 0 1 1 0 2
5 1 1 1 1 1 5
6 1 0 0 0 0 1
7 1 0 1 1 0 3
8 1 0 1 0 0 2
9 0 1 1 1 1 4
10 0 0 0 0 0 0
The experimental probability that he gets at least 2
questions right is 7 ___ 10
= 70
Copyright copy by Houghton Mifflin Harcourt 91 All rights reserved
Guided Practice
1 Since there is a 30 or 3 ___ 10
chance of drought let
the numbers 1 to 3 represent years with a drought
and the numbers 4 to 10 represent years without
a drought Since we are interested in the next 4
years perform multiple trials generating 4 random
numbers each time
2
Trial Numbers generated Drought years
1 10 3 5 1 2
2 10 4 6 5 0
3 3 2 10 3 3
4 2 10 4 4 1
5 7 3 6 3 2
6 8 4 8 5 0
7 6 2 2 8 2
8 6 5 2 4 1
9 2 2 3 2 4
10 6 3 1 5 2
3 In 8 out of the 10 trials there was a drought in at
least one of the years The experimental probability
of a drought in at least 1 of the next 4 years is
8 ___ 10
= 80
4 Sample answer Generate whole numbers from
1 to 4 Let 1 to 3 represent the event occurring
and 4 represent the event not occurring
Independent Practice
5 There is only 1 trial Trial 6 where it took exactly
4 contestants to get a winner
6 Since 1 out of 10 trials resulted in exactly
4 contestants the probability is 1 ___ 10
= 10
7 The trials for which at least 4 hurricanes struck are
Trials 2 and 7 or 2 out of 10 trials Therefore the
probability is 2 ___ 10
= 20
8 It is fewer than expected based on the simulation
9 It is unlikely but it is not impossible Each of the 3
numbers could be any number from 1 to 10
However there are 10 possible first numbers 10
possible second numbers and 10 possible third
numbers or a total of 1000 possible numbers when
generating three numbers from 1 to 10 The
probability of generating three 10s is 1 _____ 1000
10 Sample answer Use the numbers 1ndash5 where 1 2
and 3 represent packs which contain a player from
Erikarsquos favorite team Generate numbers randomly
and stop when you get a 1 2 or 3
Trial Numbers generated Number of Packs
1 3 1
2 4 2 2
3 2 1
4 1 1
5 2 1
6 4 5 3 2
7 4 2 2
8 4 5 2 1
9 4 4 3 3
10 5 1 2
The average number of packs she needs to buy is
1 + 2 + 1 + 1 + 1 + 2 + 2 + 1 + 3 + 2
_________________________________ 10
= 16 ___ 10
= 1 3 __ 5
packs Since she cannot buy a fraction of a pack
she must buy 2 packs
Focus on Higher Order Thinking
11 Sample answer The probability that she makes a
shot is 375 = 3 __ 8 Use the whole numbers from 1 to
8 with 1ndash3 representing shots she makes and 4ndash8
representing shots she misses For each new trial
generate 10 random numbers Count the number
of times 1 2 or 3 appears in each trial Divide the
number of trials in which she made at least 3 shots
by the total number of trials
12 Sample answer Their simulation was not
appropriate perhaps because they chose an
incorrect model You would expect there to have
been exactly 4 heads on more of the trials and
more variation in the number of heads in general
MODULE 13
Ready to Go On
1 P(red) = number of red marbles ___________________ total number of marbles
= 12 ___________________ 12 + 12 + 15 + 9 + 12
= 12 ___ 60
= 1 __ 5 020 or 20
2 P(diamond or spade)
= number of diamonds and spades
___________________________ total number of cards
= 13 + 13
_______ 52
= 26 ___ 52
= 1 __ 2 050 or 50
3 The most likely color of marble chosen is the most
common color in this case green
Copyright copy by Houghton Mifflin Harcourt 92 All rights reserved
4 In order to find the experimental probability count
the number of trials in which 1 occurs at least once
In this case there are 4 trials that generated a 1
Therefore the experimental probability is 4 ___ 10
or
40
5 Sample answer You can find the theoretical
probability of an event and then use it to make a
prediction by setting up a proportion
Copyright copy by Houghton Mifflin Harcourt 93 All rights reserved
Table of Contents
UNIT 1 The Number System
Module 1Lesson 11 1
Lesson 12 2
Lesson 13 3
Lesson 14 4
Module 2Lesson 21 6
Lesson 22 7
Lesson 23 8
Module 3Lesson 31 10
Lesson 32 14
Lesson 33 15
Lesson 34 17
Lesson 35 18
Lesson 36 20
UNIT 2 Ratios and Proportional
Relationships
Module 4Lesson 41 23
Lesson 42 25
Lesson 43 25
Module 5Lesson 51 28
Lesson 52 29
Lesson 53 30
UNIT 3 Expressions Equations
and Inequalities
Module 6Lesson 61 32
Lesson 62 34
Lesson 63 35
Lesson 64 37
Module 7Lesson 71 43
Lesson 72 46
Lesson 73 47
UNIT 4 Geometry
Module 8Lesson 81 53
Lesson 82 54
Lesson 83 54
Lesson 84 55
Module 9Lesson 91 57
Lesson 92 59
Lesson 93 60
Lesson 94 63
Lesson 95 65
UNIT 5 Statistics
Module 10Lesson 101 69
Lesson 102 70
Lesson 103 72
Module 11Lesson 111 74
Lesson 112 75
Lesson 113 76
Copyright copy by Houghton Mifflin Harcourt iiiAll rights reserved
Table of Contents
UNIT 6 Probability
Module 12Lesson 121 79
Lesson 122 81
Lesson 123 82
Lesson 124 82
Module 13Lesson 131 84
Lesson 132 86
Lesson 133 89
Lesson 134 91
Copyright copy by Houghton Mifflin Harcourt ivAll rights reserved
MODULE 1 Adding and Subtracting Integers
Are You Ready
1 an elevator ride down 27 stories -27
2 a $700 profit 700
3 46 degrees below zero -46
4 a gain of 12 yards 12
1 1
5 183
_ + 78
261
261
5 16 17
6 677
_ -288
389
389
1 1
7 1188
_ +902
2090
2090
1 15 14
8 2647
_ -1885
762
762
9
-8-10 -4-6 -2 2 4 6 8 100 10
-8-10 -4-6 -2 2 4 6 8 100 11
-8-10 -4-6 -2 2 4 6 8 100 12
-8-10 -4-6 -2 2 4 6 8 100
LESSON 11
Your Turn
7 -8 + ( -1 ) = -9
8 -3 + ( -7 ) = -10
9 -48 + ( -12 ) = -60
10 -32 + ( -38 ) = -70
11 109 + 191 = 300
12 -40 + ( -105 ) = -145
13 -150 + ( -1500 ) = -1650
14 -200 + ( -800 ) = -1000
Guided Practice
1 a There are 6 counters
b The red counters represent negative numbers
c -5 + ( -1 ) = -6
2 a There are 9 counters
b The red counters represent negative numbers
c -2 + ( -7 ) = -9
3 -5 + ( -2 ) = -7
-8-7-6-5 -2-1 0-4-3 4 -1 + ( -3 ) = -4
-5-4-3-2 1 2 3-1 0 5 -3 + ( -7 ) = -10
-10 -9-8-7 -4-3-2-6-5 6 -4 + ( -1 ) = -5
-5-4-3-2 1 2 3-1 0 7 -2 + ( -2 ) = -4
-5-4-3-2 1 2 3-1 0 8 -6 + ( -8 ) = -14
-16 -12 -4 0-8 9 -5 + ( -4 ) = -9
10 -1 + ( -10 ) = -11
11 -9 + ( -1 ) = -10
12 -90 + ( -20 ) = -110
13 -52 + ( -48 ) = -100
14 5 + ( 198 ) = 203
15 -4 + ( -5 ) + ( -6 ) = -15
16 -50 + ( -175 ) + ( -345 ) = -570
17 Add their absolute values Use the sign of the
integers as the sign of the sum
Solutions KeyThe Number System
UNIT
1
Copyright copy by Houghton Mifflin Harcourt 1 All rights reserved
Independent Practice
18 a
-4
-6
-8
-2
0
2
-5 + (-3)-3 + (-5)
b No -5 + ( -3 ) is -8 and -3 + ( -5 ) is also -8
19 -3 + ( -1 ) + ( -5 ) + ( -2 ) = -11 the golferrsquos total
score is -11
20 -3 + ( -6 ) = -9 the team lost a total of 9 yards
21 -14 + ( -5 ) + ( -12 ) + ( -23 ) = -54 The total
sack yardage was -54
22 a -10 + ( -8 ) = -18
b -6 + ( -2 ) = -8
c -18 lt -8 Jonestown
23 -100 + ( -75 ) + ( -85 ) = -260
Focus on Higher Order Thinking
24 a -25 + ( -45 ) + ( -75 ) = -145 Jan withdrew
$145
b -35 + ( -55 ) + ( -65 ) = -155 Julie withdrew
$155
c Sample answer $45 $55 and $65
25 It is easier to add -80 + ( -20 ) fi rst to get -100
and then add -173 to get -273
26 Disagree there are three pairs of positive integers
1 and 7 2 and 6 and 3 and 5 and three pairs of
negative integers -1 and -7 -2 and -6 -3 and
-5 The absolute value of the sum of any of these
six pairs is 8
LESSON 12
Your Turn
7 -51 + 23
ǀ -51 ǀ - ǀ 23 ǀ = 28
-51 + 23 = -28
8 10 + ( -18 )
ǀ -18 ǀ - ǀ 10 ǀ = 8
10 + ( -18 ) = -8
9 13 + ( -13 )
ǀ 13 ǀ - ǀ -13 ǀ = 0
10 25 + ( -26 )
ǀ -26 ǀ - ǀ 25 ǀ = 1
25 + ( -26 ) = -1
Guided Practice
1 9 + ( -3 ) = 6
2 3 4 5 8 9 106 7 2 -2 + 7 = 5
-3-2-1 0 3 4 51 2 3 -15 + 4 = -11
-18 -16 -12 -10-14 4 1 + ( -4 ) = -3
-5-4-3-2 1 2 3-1 0 5 -4 + 5 = 1
6 -6 + 6 = 0
7 2 + ( -5 ) = -3
8 -3 + 7 = 4
9 -8 + 14 = 6
10 7 + ( -5 ) = 2
11 5 + ( -21 ) = -16
12 14 + ( -14 ) = 0
13 0 + ( -5 ) = -5
14 32 + ( -8 ) = 24
15 To fi nd -4 + 2 start at -4 and move 2 units to the
right to -2 To fi nd the sum -4 + ( -2 ) start at -4
and move 2 units to the left to -6
Independent Practice
16 -15 + 71 = 56
17 -53 + 45 = -8
18 -79 + 79 = 0
19 -25 + 50 = 25
20 18 + ( -32 ) = -14
21 5 + ( -100 ) = -95
22 -12 + 8 + 7 = 3
23 -8 + ( -2 ) + 3 = -7
Copyright copy by Houghton Mifflin Harcourt 2 All rights reserved
24 15 + ( -15 ) + 200 = 200
25 -500 + ( -600 ) + 1200 = 100
26 9 + ( -22 ) = -13 the team lost 13 yards
27 -55 + 275 = 220 the teamrsquos profi t was $220
28 -47 + 47 = 0 Alexrsquos new balance is $0
29 Sample answer 10 and -2 and 12 and -4
30 Bart won Bartrsquos score = 123 + ( -180 ) = -57
points Samrsquos score = 185 + ( -255 ) = -70 points
-57 gt -70 so Bart has the greater score
Focus on Higher Order Thinking
31 Start at -4 and move 3 to the right to reach -1
Start at 3 and move 4 to the left to reach -1
The sums are equivalent by the Commutative
Property of Addition
32 The weight is dropped from 4 feet above the surface
Add -12 to represent the distance the weight falls
before it hits the bottom 4 + ( -12 ) = -8 The water
is 8 feet deep
33 Sample answer A model with more positive
counters than negative counters represents a sum of
two integers whose sum is positive
34 The sign of the other integer is positive and its value
is 6 or greater Sample explanation If you start at
-5 on a number line you have to move to the right 6
or more units to get a sum that is positive
LESSON 13
Your Turn
4 -7 - 2 = -7 + ( -2 )
-7 + ( -2 ) = -9
5 -1 - ( -3 ) = -1 + 3
-1 + 3 = 2
6 3 - 5 = 3 + ( -5 )
3 + ( -5 ) = -2
7 -8 - ( -4 ) = -8 + 4
-8 + 4 = -4
Guided Practice
1 5 - 8 = -3 Start with 5 positive counters
Add 3 zero pairs and remove 8 positive counters
3 negative counters are left so the difference is -3
2 -5 - ( -3 ) = -2 Start with 5 negative counters
and remove 3 negative counters 2 negative
counters are left so the difference is -2
3 -4 - 5 = -4 + ( -5 ) = -9
0-1-2-3-4-5-6-7-8-9 4 1 - 4 = 1 + -4 = -3
0 1 2 3 4-1-2-3-4 5 8 - 11 = 8 + ( -11 ) = -3
6 -3 - ( -5 ) = -3 + 5 = 2
7 15 - 21 = 15 + ( -21 ) = -6
8 -17 - 1 = -17 + ( -1 ) = -18
9 0 - ( -5 ) = 0 + 5 = 5
10 1 - ( -18 ) = 1 + 18 = 19
11 15 - 1 = 14
12 -3 - ( -45 ) = -3 + 45 = 42
13 19 - ( -19 ) = 19 + 19 = 38
14 -87 - ( -87 ) = -87 + 87 = 0
15 To subtract an integer add its opposite Sample
example 6 - 8 = 6 + ( -8 ) = -2
Independent Practice
16 To fi nd the change to Theorsquos account subtract the
initial balance -$4 from the fi nal balance $25
25 - ( -4 ) = 25 + 4 = 29
The overall change is $29
17 To fi nd the change in elevation subtract the
beginning elevation of -225 feet from the fi nal
elevation of -127 feet
-127 - ( -225 ) = -127 + 225 = 98
The change in elevation was 98 feet
18 Subtract the low temperature -2degF from the high
temperature 90degF
90 - ( -2 ) = 92
The difference between the high and low
temperatures is 92degF
19 Subtract Cheyennersquos score at the end of her turn
from her score at the start of her turn to fi nd the
change in Cheyennersquos score during her turn
-425 - ( -275 ) = -425 + 275 = -150
The change in Cheyennersquos score is -150 points
20 a Final temperature - initial temperature = change
in temperature
Gas A -8 - ( -21 ) = -8 + 21 = 13
13degC increase
Gas B 12 - ( -12 ) = 12 + 12 = 24
24degC increase
Gas C -15 - ( -19 ) = -15 + 19 = 4
4degC increase
b Negative the fi nal temperatures will be less than
the initial temperature because the gas is cooler
So the difference in temperatures will be negative
21 Diet Chow the catrsquos weight changed by
-8 + ( -18 ) = -26 ounces with Diet Chow and
3 + ( -19 ) = -16 ounces with Kitty Diet
Focus on Higher Order Thinking
22 Sample answer Susanne owed her sister $4 Then
she borrowed $10 more How much does Susanne
owe her sister in all
23 Tom found -11 - 4 instead of -11 - ( -4 ) To
subtract -4 he should add the opposite of -4
-11 + 4 = -7
Copyright copy by Houghton Mifflin Harcourt 3 All rights reserved
24 YouranswerwillbegreaterthantheintegeryoustartedwithbecausewhenyousubtractanegativeintegeryouadditsoppositeapositiveintegerForexample-5-( -3)=-5+3=-2-2gt-5
25 -16-21-26subtract5togetthenextterm
LESSON 14
Your Turn
1 Starts-Descends+Ascends-40-13+18=-53+18 =-3535feetbelowthecaveentrance
3 Usenegativeintegersforcheckamountsanduseapositiveintegerforamountdeposited-35+( -45)+180=-80+180 =100$100increase
4 JimJim-10-18+5-12=-10-18-12+5 =-( 10+18+12)+5 =-40+5 =-35Jimrestedat-35feet(35feetbelowthesurface)Carla0-20+5-18=0+5-20-18 =0+5-( 20+18) =5-38 =-33Carlarestedat-33feet(33feetbelowthesurface)
Guided Practice
1 -15+ 9- 12= -6- 12 =-1818feetbelowsealevel
2 -23+5-7=-18-7 =-25-25degF
3 50-40+87-30=10+87-30 =97-30 =6767points
4 -6+15+15=-6+30 =24
5 9- 4- 17= 9- 21 =-12
6 50-42+10=8+10 =18
7 6+13+7-5=19+2 =21
8 65+43-11=108-11 =97
9 -35-14+45+31=-49+76 =27
10 -12+6-4=-6-4 =-10-34-3+39=-37+39 = 2 -10lt2( -12+6-4)lt( -34-3+39)
11 21-3+8=18+8 =26-14+ 31- 6= 17- 6 =11 26gt11( 21-3+8)gt( -14+31-6)
12 SampleanswerAddandsubtractfromlefttoright-5+12+10-7=7+10-7=17-7=10
Independent Practice
13 a 5-1+6-1=9
b 9isapositivescoresoitisoverpar
c 9overparislessthan15overparYesCameronbeathisbestgolfscore
14 -6+14-11=-33feetunderground
15 TheCommutativePropertydoesnotapplytosubtraction3-6+5=2and3-5+6=4
16 a -350+275+70-50=-55Leersquosfinalscoreis-55points
b 45gt-55Barry
17 a 300to400
b 75+30-12+14-8+18-30=75+18+6-12=8787customersmustleavebetween400and500
18 100-18+22-53=51$51
19 45-17-22+18=24$24
20 Carlarsquosaccountdecreased$49-18+22-53=-49andLetarsquosaccountonlydecreased$21-17-22+18=-21Carlarsquosaccounthadthegreatestdecreaseinvalue
Focus on Higher Order Thinking
21 SampleanswerTimoweshisbrother1dollarHeborrows6moredollarsfromhisbrotherHepayshisbrotherback3dollarsHowmuchdoesTimstillowehisbrother-1-6+3=-4$4
22 Nothetotalamountshecouldpayherparentsis10+12+25=47and50-47=3Soshestillneeds$3
23 SampleanswerInthecaseinwhichthefirstnumberispositivethenthesumoftheabsolutevaluesoftheothertwonumbersmustbegreaterthanthevalueofthefirstnumberSampleexample13-5-10=-2ǀ 5ǀ+ǀ 10ǀ=15whichisgreaterthan13
MODULE 1
Ready to Go On
1 -8+( -6)=-14
2 -4+( -7)=-11
3 -9+( -12)=-21
CopyrightcopybyHoughtonMifflinHarcourt 4 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U1M01indd 4 103113 206 AM
4 5 + ( -2 )
ǀ 5 ǀ - ǀ -2 ǀ = 3
5 + ( -2 ) = 3
5 -8 + 4
ǀ -8 ǀ - ǀ 4 ǀ = 4
-8 + 4 = -4
6 15 + ( -8 )
ǀ 15 ǀ - ǀ -8 ǀ = 7
15 + ( -8 ) = 7
7 2 - 9 = 2 + ( -9 )
2 + ( -9 ) = -7
8 -3 - ( -4 ) = -3 + 4-3 + 4 = 1
9 11 - ( -12 ) = 11 + 12
11 + 12 = 23
10 -15 + 9 - 4 = -6 - 4
= -10
There are 10 fewer people on the bus
11 24 + 8 - 12 - 9 = 24 + 8 - ( 12 + 9 ) = 32 - 21
= 11
There are 11 cards left in the stack
12 Sample answer Tonya owes her sister $10 and
her friend $5 By how much will her savings change
after she pays them
-10 + ( -5 ) = -15 $15 decrease
Copyright copy by Houghton Mifflin Harcourt 5 All rights reserved
MODULE 2 Multiplying and Dividing Integers
Are You Ready
1 9 times 3 = 27
2 7 times 10 = 70
3 9 times 8 = 72
4 15 times 10 = 150
5 6 times 9 = 54
6 10 times 23 = 230
7 9 times 9 = 81
8 10 times 20 = 200
9 54 divide 9 = 6
10 42 divide 6 = 7
11 24 divide 3 = 8
12 64 divide 8 = 8
13 90 divide 10 = 9
14 56 divide 7 = 8
15 81 divide 9 = 9
16 110 divide 11 = 10
17 12 + 8 divide 212 + 4
16
18 15 - ( 4 + 3 ) times 2
15 - 7 times 2
15 - 14
1
19 18 - ( 8 - 5 ) 2
18 - ( 3 ) 2
18 - 9
9
20 6 + 7 times 3 - 5
6 + 21 - 5
27 - 5
22
21 9 + ( 2 2 + 3 ) 2 times 2
9 + ( 4 + 3 ) 2 times 2
9 + ( 7 ) 2 times 2
9 + 49 times 2
9 + 98
107
22 6 + 5 - 4 times 3 divide 2
6 + 5 - 12 divide 2
6 + 5 - 6
11 - 6
5
LESSON 21
Your Turn
4 Since the numbers have opposite signs the product
will be negative
ǀ -3 ǀ times ǀ 5 ǀ = 3 times 5 = 15
-3 ( 5 ) = -15
5 Since the numbers have the same sign the product
will be positive
ǀ -10 ǀ times ǀ -2 ǀ = 10 times 2 = 20
( -10 ) ( -2 ) = 20
6 One of the factors is 0 so the product is 0
0 ( -22 ) = 0
7 Since the numbers have the same sign the product
will be positive
8 ( 4 ) = 32
Guided Practice
1 -1 ( 9 ) = -9
2 14 ( -2 ) = -28
3 ( -9 ) ( -6 ) = 54
4 ( -2 ) ( 50 ) = -100
5 ( -4 ) ( 15 ) = -60
6 -18 ( 0 ) = 0
7 ( -7 ) ( -7 ) = 49
8 -15 ( 9 ) = -135
9 ( 8 ) ( -12 ) = -96
10 -3 ( -100 ) = 300
11 0 ( -153 ) = 0
12 -6 ( 32 ) = -192
13 7 ( -75 ) = -525 -$525
14 Start at zero and move 5 units to the left 3 times
3 ( -5 ) = -15 the team lost 15 yards
15 6 ( -2 ) = -12 -12degF
16 Multiply the absolute values of the integers If both
integers have the same sign the product is positive
If they have different signs the product is negative
Independent Practice
17 No her number line shows the correct result -6
but she modeled 2 ( -3 ) instead of -2 ( 3 )
18 2 ( -3 ) = -6 he went down 6 floors
19 5 ( -4 ) = -20 $20 decrease
20 Adam descended 5 feet a total of 5 times
5 ( -5 ) = -25 Adam is 25 feet below sea level
21 7 ( -6 ) = -42 the cost of the jeans decreased by
$42 over the 7 weeks
22 9 ( -6 ) = -54 -54 ( 2 ) = -108 Casey has $108
less in his savings
23 7 ( -8 ) = -56 7 ( -5 ) = -35
-56 + ( -35 ) = -91 The savings decreased by $91
24 Sample answer Dave plays a video game in which
he loses 20 points every time he misses a goal
He misses 8 goals 8 ( -20 ) = -160 he loses
160 points
Copyright copy by Houghton Mifflin Harcourt 6 All rights reserved
25 a 3 ( 3 ) ( -3 ) = 9 ( -3 ) = -27
b 3 ( -3 ) ( -3 ) = -9 ( -3 ) = 27
c -3 ( -3 ) ( -3 ) = 9 ( -3 ) = -27
d 3 ( 3 ) ( 3 ) ( -3 ) = 9 ( 3 ) ( -3 ) = 27 ( -3 ) = -81
e 3 ( 3 ) ( -3 ) ( -3 ) = 9 ( -3 ) ( -3 ) = -27 ( -3 ) = 81
f 3 ( -3 ) ( -3 ) ( -3 ) = -9 ( -3 ) ( -3 ) = 27 ( -3 ) = -81
g When a product of integers has an odd number of
negative factors like -3 ( -3 ) ( -3 ) = -27 and
3 ( 3 ) ( 3 ) ( -3 ) = -81 the sign of the product is
negative
When a product of integers has an even number
of negative factors like ( 3 ) ( -3 ) ( -3 ) = 27 and
3 ( 3 ) ( -3 ) ( -3 ) = 9 ( -3 ) ( -3 ) = 81 the sign of the
product is positive
Focus on Higher Order Thinking
26 -1 ( 3 ) ( 1 ) 1 ( -3 ) ( 1 ) -1 ( -3 ) ( -1 )
27 Unless one of the factors is 0 whenever the factors
have opposite signs the product will be less than or
equal to both of the two factors
28 The sign of the product is equal to the sign of the
integers The sign of the product of the first two
integers will always be positive Multiplying this
product by the remaining factor will make a positive
product if the factor is positive negative if it is
negative
LESSON 22
Your Turn
2 Since only the dividend is zero the quotient is 0
0 divide ( -6 ) = 0
3 Since the numbers have opposite signs the quotient
will be negative
38 divide ( -19 ) = -2
4 Since the numbers have the same sign the quotient
will be positive
-13 divide ( -1 ) = 13
5 Yolanda received the same number of penalties in
each game -25 divide ( -5 ) = 5 and -35 divide ( -7 ) = 5
Guided Practice
1 -14 ____ 2 = -7
2 21 divide ( -3 ) = -7
3 26 ____ -13
= -2
4 0 divide ( -4 ) = 0
5 -45 ____ -5 = 9
6 -30 divide ( 10 ) = -3
7 -11 ____ -1
= 11
8 -31 divide ( -31 ) = 1
9 0 ___ -7 = 0
10 -121 _____ -11
= 11
11 84 divide ( -7 ) = -12
12 500 ____ -25
= -20
13 -6 divide ( 0 ) = undefined any number divided by 0 is
undefined
14 -63 ____ -21
= 3
15 -40 divide ( 4 ) = -10 $10
16 -22 divide ( 11 ) = -2 2 points
17 -75 divide ( -15 ) = 5 5 targets
18 -99 divide ( -9 ) = 11 11 times
19 In both cases if the signs of the initial numbers are
the same the answer will be positive If the signs are
different the answer will be negative
Independent Practice
20 -24 divide ( 12 ) = -2 $2
21 Elisa made a greater number of withdrawals She
made -140 divide ( -20 ) = 7 withdrawals Francis made
-270 divide ( -45 ) = 6 withdrawals and 7 gt 6
22 a -2 - 10 = -12 the temperature decreased 12degF
b -12 divide ( 12 ) = -1 decreased by 1degF each hour
23 The first part the rate of change for the first part
is -200 ft _______ 10 min
= -20 ftmin and the rate of change for
the second part is -300 ft _______ 20 min
= -15 ftmin
20 ftmin gt 15 ftmin
24 Sample answer A football team lost 50 yards due to
5 penalties If the team lost the same number of
yards for each penalty what was the change in field
position for each penalty
25 Sample answer a = - 20 and b = 5 less than
-20 divide 5 = -4 and -20 times 5 = -100
-100 lt -4
26 True if the integers have the same sign the product
and quotient are positive if they have different signs
negative
27 False division by 0 is undefined for any dividend
Focus on Higher Order Thinking
28 a 100 divide 25 = 4 4 points
b -16 divide ( -4 ) = 4 Fred answered 4 questions
incorrectly
29 a divide ( -3 ) = 8
a = -24
8 divide b = -4
a divide b = -24 divide ( -2 ) = 12
Copyright copy by Houghton Mifflin Harcourt 7 All rights reserved
30 Dividing integers with the same sign results in a
positive number Since the original two integers are
negative the quotient is greater than both of these
integers
LESSON 23
Your Turn
1 Reggie earned 110 points
3 ( -30 ) + 200 = -90 + 200
= 110
2 -6 ( 13 ) - 21 = -78 - 21
= -99
4 ( -12 ) divide 6 + 2 = -2 + 2
= 0
5 -87 divide ( -3 ) -9 = 29 - 9
= 20
6 40 divide ( -5 ) + 30 = -8 + 30
= 22
7 -39 divide 3 -15 = -13 - 15
= -28
8 Amber moved 3 ( -3 ) + 5 = -4 or 4 places back
Will moved 2 ( -4 ) + 3 = -5 or 5 places back Will
moved further back
9 ( -10 ) divide 2 - 2 = -5 - 2 = -7
( -28 ) divide 4 + 1 = -7 + 1 = -6
10 42 divide ( -3 ) + 9 = -14 + 9 = -5
( -36 ) divide 9 - 2 = -4 - 2 = -6
Guided Practice
1 -6 ( -5 ) + 12 = 30 + 12
= 42
2 3 ( -6 ) - 3 = -18 - 3
= -21
3 -2 ( 8 ) + 7 = -16 + 7
= -9
4 4 ( -13 ) + 20 = -52 + 20
= -32
5 -4 ( 0 ) - 4 = 0 - 4
= -4
6 -3 ( -5 ) - 16 = 15 - 16
= -1
7 7 ( -5 ) + 20 = -35 + 20
= -15
15 dollars less
8 7 ( -10 ) + ( -100 ) = -70 + ( -100 )
= -170
170 fewer points
9 6 ( -4 ) + 10 = -24 + 10
= -14
Ned lost 14 points
10 4 ( -12 ) + 10 = -48 + 10
= -38
$38 less
11 -3 ( -2 ) + 3 = 6 + 3
= 9
3 ( -4 ) + 9 = -12 + 9
= -3
9 gt -3
-3 ( -2 ) + 3 gt 3 ( -4 ) + 9
12 -8 ( -2 ) -20 = 16 -20
= -4
3 ( -2 ) + 2 = - 6 + 2
= -4
-4 = -4
-8 ( -2 ) -20 = 3 ( -2 ) + 2
13 -7 ( 5 ) - 9 = -35 - 9
= -44
-3 ( 20 ) + 10 = -60 + 10
= -50
-44 gt -50
-7 ( 5 ) -9 gt -3 ( 20 ) + 10
14 -16 ( 0 ) -3 = 0 -3
= -3
-8 ( -2 ) -3 = 16 -3
= 13
-3 lt 13
-16 ( 0 ) -3 lt -8 ( -2 ) -3
15 A negative number usually represents a debt
payment or loss or a change that is a decrease
such as to a savings account
Independent Practice
16 -12 ( -3 ) + 7 = 36 + 7
= 43
17 -42 divide ( -6 ) + 5 -8 = 7 + 5 -8
= 12 -8
= 4
18 10 ( -60 ) -18 = -600 -18
= -618
19 ( -11 ) ( -7 ) + 5 - 82 = 77 + 5 - 82
= 82 - 82
= 0
20 35 divide ( -7 ) + 6 = -5 + 6
= 1
21 -13 ( -2 ) - 16 - 8 = 26 - 16 - 8
= 10 - 8
= 2
22 a 5 ( 2 ) -12 + 3 = 10 -12 + 3
= -2 + 3
= 1
b -3 ( 2 ) -1 + 6 + 7 = -6 -1 + 6 + 7
= -7 + 6 + 7
= -1 + 7
= 6
c Rose has more points than Lily so Rose won
the game
23 5 ( -4 ) -8 = -20 - 8 = -28
24 -36 divide ( -4 ) + 9 = 9 + 9 = 18
Copyright copy by Houghton Mifflin Harcourt 8 All rights reserved
25 a 4 ( -35 ) -9 = -140 -9
= -149
$149 less
b Yes $200 - $149 = $51 $51 gt $50 so Arleen
has enough money
26 a 2 ( -10 ) + 3 = -20 + 3= -17
b 7 + 2 + ( -7 ) = 2
c Warren since 2 is greater than -17
d Sample answer 2 of clubs 2 of spades
3 of spades king of diamonds 10 of clubs
7 of clubs
Focus on Higher Order Thinking
27 Sample answer Ann bought three shirts for $7 each
and a pair of pants for $10 Her mother gave her
$25 By how much did the amount of money Ann
had change
28 Disagree the quotient of two integers is positive if
the integers have the same sign So the first two
integers could have been negative integers
29 5 feet equals 60 inches so Lisa is holding the rock
60 inches above the waterrsquos surface The rock will
travel 4 times -5 = -20 inches or 20 inches below the
surface in 4 seconds 60 + 20 = 80 inches
MODULE 2
Ready to Go On
1 Since the numbers have opposite signs the product
will be negative
( -2 ) ( 3 ) = -6
2 Since the numbers have the same sign the product
will be positive
( -5 ) ( -7 ) = 35
3 Since the numbers have the opposite signs the
product will be negative
( 8 ) ( -11 ) = -88
4 ( -3 ) ( 2 ) ( -2 ) = ( -6 ) ( -2 ) = 12
5 5 ( -3 ) = -15 -15degC
6 -63 ____ 7 = -9
7 -15 ____ -3
= 5
8 0 ____ -15
= 0
9 96 ____ -12
= -8
10 -24 divide 6 = -4 -4 Ib
11 ( -4 ) ( 5 ) + 8 = -20 + 8
= -12
12 ( -3 ) ( -6 ) -7 = 18 -7
= 11
13 -27 ____ 9 - 11 = -3 - 11
= -14
14 -24 ____ -3
- ( -2 ) = 8 + 2
= 10
15 Sample answer Maurice lost 3 nickels in the laundry
and found 1 dime in the couch By how much did the
amount of money he had change
( -3 ) ( 5 ) + 10 = -15 + 10 = -5 He had $05 less
than before
Copyright copy by Houghton Mifflin Harcourt 9 All rights reserved
MODULE 3 Rational Numbers
Are You Ready
1 9 ___ 14
times 7 __ 6 =
3
2
9 ___ 14
times 7 __ 6 1
2
= 3 __ 4
2 3 __ 5 times 4 __
7 = 12 ___
35
3 11 ___ 8
times 10 ___ 33
= 1
4
11 ___ 8 times 10 ___
33 5
3
= 5 ___ 12
4 4 __ 9 times 3 =
3
4 __ 9 times 3 __
1 1
= 4 __ 3 or 1 1 __
3
5 1 __ 2 divide 1 __
4 = 1 __
2 times 4 __
1
=
1 1 __ 2 times 4 __
1 2
= 2 __ 1 = 2
6 3 __ 8 divide 13 ___
16 = 3 __
8 times 16 ___
13
= 1 3 __ 8 times 16 ___
13 2
= 6 ___ 13
7 2 __ 5 divide 14 ___
15 = 2 __
5 times 15 ___
14
= 1
1 2 __ 5 times 15 ___
14 3
7
= 3 __ 7
8 4 __ 9 divide 16 ___
27 = 4 __
9 times 27 ___
16
= 1
1 4 __ 9 times 27 ___
16 3
4
= 3 __ 4
9 3 __ 5 divide 5 __
6 = 3 __
5 times 6 __
5
= 18 ___ 25
10 1 __ 4 divide 23 ___
24 = 1 __
4 times 24 ___
23
= 1 1 __ 4 times 24 ___
23 6
= 6 ___ 23
11 6 divide 3 __ 5 = 6 __
1 times 5 __
3
= 2
6 __ 1 times 5 __
3 1
= 10 ___ 1 = 10
12 4 __ 5 divide 10 = 4 __
5 times 1 ___
10
= 2
4 __ 5 times 1 ___
10 5
= 2 ___ 25
13 21 - 6 divide 3
21 - 2
19
14 18 + ( 7 - 4 ) times 3
18 + 3 times 3
18 + 9
27
15 5 + ( 8 - 3 ) 2
5 + ( 5 ) 2
5 + 25
30
16 9 + 18 divide 3 + 10
9 + 6 + 10
15 + 10
25
17 60 - ( 3 - 1 ) 4 times 3
60 - ( 2 ) 4 times 3
60 - 16 times 3
60 - 48
12
18 10 - 16 divide 4 times 2 + 6
10 - 4 times 2 + 6
10 - 8 + 6
2 + 6
8
LESSON 31
Your Turn
0 _
571428
4 7 ⟌ _
40000000 Dividing into 40
_ -35
50
_ -49
10
_ -7
30
_ -28
20
_ -14
60
_ -56
40 Second appearance of 40
Because the number 40 repeats during the division
process the answer is a repeating decimal
-0 _
571428 or -0571428571428hellip
Copyright copy by Houghton Mifflin Harcourt 10 All rights reserved
0 _ 3
5 3 ⟌ _
100 Dividing into 10
_ -3
10 Second appearance of 10
Because the number 10 repeats during the division
process the answer is a repeating decimal 0 _ 3 or
0333hellip
045
6 20 ⟌ _
900
_ -8 0
1 00
_ -1 00
0
-045
7 -2 3 __ 4 = -thinsp 4 times 2 + 3
_________ 4 = -11 ____
4
275
4 ⟌ _
1100
_ -8
30
_ -28
20
_ -20
0
-275 terminating
8 7 1 __ 3 =
3 times 7 + 1 _________
3 = 22 ___
3
7 _ 3
3 ⟌ _
2200 Dividing into 10
_ -21
1 0 Second appearance of 10
Because the number 10 repeats during the division
process the answer is a repeating decimal 7 _ 3 or
7333hellip repeating
Guided Practice
06
1 5 ⟌ _
30
_ -3 0
0
06 terminating
089
2 100 ⟌ _
8900
_ -80 0
9 00
_ -9 00
0
-089 terminating
3 Simplify the fraction
4 ___ 12
= 4 times 1 _____ 4 times 3
= 1 __ 3
0 _ 3
3 ⟌ _
100 Dividing into 10
_ -3
10 Second appearance of 10
Because the number 10 repeats during the division
process the answer is a repeating decimal 0 _ 3 or
0333hellip repeating
0 _
25
4 99 ⟌ _
25000 Dividing into 25
_ -19 8
520
_ -495
25 Second appearance of 25
Because the number 25 repeats during the division
process the answer is a repeating decimal 0 _
25 or
02525hellip repeating
0 _ 7
5 9 ⟌ _
700 Dividing into 70
_ -63
70 Second appearance of 70
Because the number 70 repeats during the division
process the answer is a repeating decimal 0 _ 7 or
-0777hellip repeating
036
6 25 ⟌ _
900
_ -7 5
1 50
_ -1 50
0
-036 terminating
004
7 25 ⟌ _
100
_ -1 00
0
004 terminating
01420 _
45
8 176 ⟌ _
250000000
_ -17 6
7 40
_ -7 04
360
_ -352
80
_ -0
800 First appearance of 800
_ -704
960
_ -880
800 Second appearance of 800
Because the number 800 repeats during the
division process the answer is a repeating decimal
-01420 _
45 or -014204545hellip repeating
0012
9 1000 ⟌ _
12000
_ -10 00
2 000
_ -2 000
0
0012 terminating
Copyright copy by Houghton Mifflin Harcourt 11 All rights reserved
10 -11 1 __ 6 = -thinsp 6 times 11 + 1
_________ 6 = -67 ____
6
111 _ 6
6 ⟌ _
67000
_ -6
07
_ -6
1 0
_ -6
40 First appearance of 40
_ -36
40 Second appearance of 40
Because the number 40 repeats during the division
process the answer is a repeating decimal
- 67 ___ 6
-111 _ 6 or -111666hellip
11 2 9 ___ 10
= 10 times 2 + 9
__________ 10
= 29 ___ 10
29
10 ⟌ _
290
_ -20
9 0
_ -9 0
0
29 ___ 10
29
12 -8 23 ____ 100
= - 100 times 8 + 23
____________ 100
= -823 _____ 100
823
100 ⟌ _
82300
_ -800
23 0
_ -20 0
3 00
_ -3 00
0
-823 _____ 100
-823
13 7 3 ___ 15
= 15 times 7 + 3
__________ 15
= 108 ____ 15
72
15 ⟌ _
1080
_ -105
3 0
_ -3 0
0
108 ____ 15
72
14 54 3 ___ 11
= 11 times 54 + 3
__________ 11
= 597 ____ 11
54 _
27
11 ⟌ _
597000
_ -55
47
_ -44
30 First appearance of 30
_ -22
80
_ -77
30 Second appearance of 30
Because the number 30 repeats during the division
process the answer is a repeating decimal
597 ____ 11
54 _
27 or 542727hellip
15 -3 1 ___ 18
= -thinsp 18 times 3 + 1 __________
18 = -55 ____
18
30 _ 5
18 ⟌ _
55000
_ -54
1 0
_ -0
1 00 First appearance of 100
_ -90
100 Second appearance of 100
Because the number 100 repeats during the division
process the answer is a repeating decimal
-55 ____ 18
-30 _ 5 or -30555hellip
16 3 2 __ 3 =
3 times 3 + 2 _________
3 = 11 ___
3
3 _ 6
3 ⟌ _
1100
_ -9
2 0 First appearance of 20
_ -1 8
20 Second appearance of 20
Because the number 20 repeats during the division
process the answer is a repeating decimal
3 _ 6 or 3666hellip lbs of apples
17 -2 7 __ 8 = -
8 times 2 + 7 _________
8 = -23 ____
8
2875
8 ⟌ _
23000
_ -16
7 0
_ -6 4
60
_ -56
40
_ -40
0
-2875 lb
18 Disagree the definition of a rational number is a
number that can be written as the ratio of two
integers with a denominator not equal to zero and
3 ___ 47
is a well-defined ratio of two integers Tom did
not divide long enough to correctly determine that
the quotient is a repeating decimal
Copyright copy by Houghton Mifflin Harcourt 12 All rights reserved
Independent Practice
19 basketball players
_______________ football players
= 5 ___ 11
0 _
45
11 ⟌ _
5000 Dividing into 50
_ -4 4
60
_ -55
50 Second appearance of 50
Because the number 50 repeats during the division
process the answer is a repeating decimal
5 ___ 11
0 _
45 or 04545hellip repeating
20 hockey players
______________ lacrosse players
= 6 ___ 10
06
10 ⟌ _
60
_ -6 0
0
6 ___ 10
06 terminating
21 polo players
_____________ football players
= 4 ___ 11
036
11 ⟌ _
4000 Dividing into 40
_ -3 3
70
_ -66
40 Second appearance of 40
Because the number 40 repeats during the division
process the answer is a repeating decimal
4 ___ 11
0 _
36 or 03636hellip repeating
22 lacrosse players
______________ rugby players
= 10 ___ 15
= 5 times 2 _____ 5 times 3
= 2 __ 3
0 _ 6
3 ⟌ _
200 Dividing into 20
_ -1 8
20 Second appearances of 20
Because the number 20 repeats during the division
process the answer is a repeating decimal
10 ___ 15
0 _ 6 or 0666hellip repeating
23 football players
_____________ soccer players
= 11 ___ 11
= 1
11 ___ 11
1 terminating
24 Agree Sample answer There are 10 players on the
lacrosse team and dividing the number of any other
team by 10 will simply move the decimal point one
digit to the left Therefore the ratio of any team over
the lacrosse team will be a decimal that terminates
one place to the right of the decimal point
25 a -4 7 __ 8 = -thinsp 8 times 4 + 7
_________ 8 = - 39 ___
8
b 4875
8 ⟌ _
39000
_ -32
7 0
_ -6 4
60
_ -56
40
_ -40
0
-4875
c Sample answer 4 7 __ 8 is very close to 5 Therefore
You could estimate that the water level changes
by 5 inches per month The total change in the
water level at the end of the 3-month period
would be approximately -15 inches
26 integer terminating
27 Ben is taller because Benrsquos height of 5 5 ___ 16
is equal
to 85 ___ 16
or 53125 ft while Marcusrsquo height of 5 7 ___ 24
is
equal to 127 ____ 24
or 52916hellip ft
28 The first store has the better deal because they
offer 3 __ 4 or 075 of a bushel for $9 while the second
store offers only 2 __ 3 or 0666hellip of a bushel for $9
Focus on Higher Order Thinking
29 When the number 1 is the denominator in a fraction
its decimal form is simply the numerator In all other
cases concerning numbers 1 to 10 the division
process stops when either the remainder is 0 or
when the digits begin to repeat When the numbers
2 4 5 or 8 are in the denominator the decimal form
of a fraction will terminate When the numbers
3 6 7 or 9 are in the denominator the decimal form
of a fraction will be a repeating decimal
30 Julie made a higher score on her math test since
her math test score of 21 ___ 23
is equal to a repeating
decimal of approximately 0913 while her science
test score of 29 ___ 32
is equal to a terminating decimal of
090625
Sample answer The difference in scores cannot be
determined by simply comparing the numerators of
the two fractions because the denominators are not
the same For Julie to compare her scores she
needs to divide the denominators into their respec-
tive numerators until one of the quotients is found to
be greater than the other
31 No although the digits in the decimal appear to
follow a pattern a repeating decimal must have the
same combination of digits that repeat such as
0121212hellip
Copyright copy by Houghton Mifflin Harcourt 13 All rights reserved
LESSON 32
Your Turn
2
50 1 2 3 4
3 + 1 1 __ 2 = 4 1 __
2
3
0-7 -6 -5 -4 -3 -2 -1
-25 + ( -45 ) = -7
6
0 1 2-5-6-7-8 -4 -3-2-1
-8 + 5 = -3
7
10-1
1 __ 2 + ( - 3 __
4 ) = - 1 __
4
8
3 4 5 6 7 80 1 2-3-2-1
-1 + 7 = 6
9
3 4 50 1 2-5-4 -3-2-1
2 1 __ 2 + ( -2 1 __
2 ) = 0
10
3 4 50 1 2-5-4 -3-2-1
-45 + 45 = 0
11
1-1 0
3 __ 4 + ( - 3 __
4 ) = 0
The overall change is 0 cups
12 -15 + 35 + 2
-15 + 55
55 - 15
4
13 3 1 __ 4 + ( -2 ) + ( -2 1 __
4 )
3 1 __ 4 + ( -4 1 __
4 )
3 1 __ 4 - 4 1 __
4
-1
14 -275 + ( 325 ) + 5
-6 + 5
-1
15 15 + 8 + ( -3 )
23 + 3
20
Guided Practice
1
3 4 50 1 2-5-4 -3-2-1
-3 + ( -15 ) = -45
2
0 54321-5-4-3-2-1
15 + 35 = 5
3
0 105-1 -05
1 __ 4 + 1 __
2 = 3 __
4
4
0 54321-5-4-3-2-1
-1 1 __ 2 + ( -1 1 __
2 ) = -3
5
0 54321-5-4-3-2-1
3 + ( -5 ) = -2
6
0 54321-5-4-3-2-1
-15 + 4 = 25
7 -2150 + 2150 = 0 $0
8 -874 + 874 = 0 $0
9 275 + ( -2 ) + ( -525 )
275 + ( -725 )
- ( 725 - 275 )
-45
10 -3 + 1 1 __ 2 + 2 1 __
2 = -3 + 4 = 1
11 124 + 92 + 1
-124 + 102
- ( 124 - 102 )
-22
12 -12 + 8 +13
-12 + 21
21 - 12
9
13 45 + ( -12 ) + ( -45 )
45 + ( -45 ) + ( -12 )
0 + ( -12 )
-12
14 1 __ 4 + ( - 3 __
4 ) = - ( 3 __
4 - 1 __
4 ) = - 2 __
4 = - 1 __
2
Copyright copy by Houghton Mifflin Harcourt 14 All rights reserved
15 -4 1 __ 2 + 2 = - ( 4 1 __
2 - 2 ) = -2 1 __
2
16 -8 + ( -1 1 __ 8 ) = -9 1 __
8
17 Start at -4 and move 6 units to the right
The sum is 2
Independent Practice
18 The opposite of +19 is -19
19 -$225 + $1500 = $1500 - $225 = $1275
20 -3525 m + ( -85 ) = -4375 m
21 4 3 __ 4 mi + ( -3 1 __
4 mi ) = 1 2 __
4 mi = 1 1 __
2 mi
22 1635 m + ( -05 m ) = 163 m above sea level
23 30 + 15 - 25 = 45 - 25 = 20 pts
24 January
Income - Expenses
$1205 - $129060
- ( $129060 - $1205 ) -$8560
February
Income - Expenses
$1183 - $134544
-($134544 - $1183)
-$16244
Kameh lost $8560 in January and $16244 in
February
25 June
Income - Expenses
$2413 - $210623
$30677
July
Income - Expenses
$2260 - $195850
$30150
August
Income - Expenses
$2183 - $184512
$33788
Kameh gained $30677 in June $30150 in July and
$33788 in August
26 First sum all the values in the Income column Then
sum all the values in the Expenses column Subtract
the total expenses from the total income Finally add
the $250 profit from December (not shown in the
table) to find the total profit or loss of the bakery by
the end of August
Income = $1205 + $1183 + $1664 + $2413
$2260 + $2183 = $10908
Expenses = $129060 + $134544 + $1664 +$210623 + $195850 + $184512
= $1020989
Profit = $10908 - $1020989 + $250
= $94811
27 -2 is the opposite or additive inverse of 2
28 a 7 ( 10 ) + 3 ( -15 ) = 70 - 45 = 25 pts
b 2 ( 10 ) + 8 ( -15 ) = 20 - 120 = -100 pts
c 10 + 10 + 10 + 10 + 10 + ( ndash15 ) + ( ndash15 ) + ( ndash15 ) +
( ndash15 ) + ( ndash15 ) or 5 ( 10 ) + 5 ( ndash15 )
Focus on Higher Order Thinking
29 The sum of two negative rational numbers is always
negative The sum of a negative rational number and
a positive rational number is negative if the absolute
value of the negative number is greater than that of
the positive number
30 Sample answer The student might have subtracted
the absolute values of the numbers
31 Yes 55 and -55 are opposites and -23 and 23
are opposites so the expression [ 55 + ( -23 ) ] +
( -55 + 23 ) can be viewed as the sum of two
opposites which is always 0
LESSON 33
Your Turn
1
-9 -8 -7 -6 -5 -4
-65 - 2 = -85
2
42 30-1 1
1 1 __ 2 - 2 = - 1 __
2
3
-10-9 -8 -7 -6 -5 -4 -3 -2 -1 0
-225 - 55 = -775
6
1 2-1 0
025 - ( -150 ) = 175
7
1-1 0
- 1 __ 2 - ( - 3 __
4 ) = 1 __
4
Guided Practice
1
1312111098765 14 15
5 - ( -8 ) = 13
2
-9 -8 -7 -6 -5 -4 -3
3 1 __ 2 - 4 1 __
2 = -8
Copyright copy by Houghton Mifflin Harcourt 15 All rights reserved
3
-15 -13 -11 -9 -5-7
-7 - 4 = -11
4
-6 -5 -4 -3 -2 -1 0 1
-05 - 35 = -4
5 -14 - 22 = -36
6 -125 - ( -48 )
-125 + 48
- ( 125 - 48 )
-77
7 1 __ 3 - ( - 2 __
3 ) = 1 __
3 + 2 __
3 = 1
8 65 - ( -14 ) = 65 + 14 = 79
9 - 2 __ 9
- ( -3 )
- 2 __ 9
+ 3
3 - 2 __ 9
2 9 __ 9 - 2 __
9
2 7 __ 9
10 24 3 __ 8
- ( -54 1 __ 8 )
24 3 __ 8
+ 54 1 __ 8
78 4 __ 8
78 1 __ 2
11 -1 m + ( 105 m ) = -15 m
15 m below sea level
12 -12 1 __ 2 + ( -5 ) = -17 1 __
2
17 1 __ 2
or 175 yards
13 Change in height = Starting height - ending height
533 ft - ( -10 ft ) = 533 ft + 10 ft = 543 ft
14 -4500 + (-3015) = -7515 $7515
15 Explain that she is supposed to start at positive 4 on
the number line then move 12 places to the left
because she is subtracting a positive number She
will end on the number -8 which is the answer
Independent Practice
16 -126degC - 75degC = -201degC
17 -2565 ft - 165 ft + 1245 ft = -297 ft
The diver is 297 ft below the surface
18 -9500 ft - ( -26000 ft ) = 16500 ft
19 29035 ft - ( -36198 ft ) = 65233 ft
70000 ft - ( -26000 ft ) = 96000 ft
Mars has the greater difference by
96000 ft - ( 65233 ft ) = 30767 ft
20 a -5degF + 78degF - 32degF
b 78degF - 32degF
c -5degF + 78degF - 32degF 78degF - 5degF - 32degF 78degF - 37degF = 41degF 78degF - 32degF = 46degF
21 a -$1258 + ( -$3072 ) = -$4330
b -$4330 + ( -$25 ) = -$6830
c $6830 since -$6830 + $6830 = 0
22 a No 4 times 52 in = 208 in
b 208 in - 20 in = 08 in more needed
23 a 5 ft - 72 ft + 22 ft
b 5 ft - 72 ft + 22 ft
5 ft + 22 ft - 72 ft
72 ft - 72 ft
= 0 ft because he moved the same distance
backward and forward
24 a Yes
$425 + $089 + $1099
= $1613 lt $20
b $20 - $1613 = $387 left over
Focus on Higher Order Thinking
25 The Commutative Property of Addition (CPA) could
be used to simplify the two terms that already have
a common denominator first
- 7 ___ 16
- 1 __ 4 - 5 ___
16 = ( - 7 ___
16 ) + ( - 1 __
4 ) + ( - 5 ___
16 )
( - 7 ___ 16
) + ( - 5 ___ 16
) + ( - 1 __ 4 ) by CPA
( -7 + ( -5 ) __________
16 ) + ( - 1 __
4 )
( -12 ____ 16
) + ( - 1 __ 4 )
( - 4 times 3 _____ 4 times 4
) + ( - 1 __ 4 )
( - 3 __ 4 ) + ( - 1 __
4 )
( -3 + ( -1 ) __________
4 )
( -4 ___ 4 ) = -1
26 Lowest -225degF + ( -12degF ) = -345degFHighest -195degF + ( -12degF ) = -315degF
27 Sample answer Yes because both numbers are
rational numbers each can be written as the ratio of
two integers for example a __ b
and c __ d
Both fractions
could be given a common denominator and then
one could then be subtracted from the other The
result would be a fraction which is a rational number
28 No Sample answer It is possible for the
difference of two negative numbers to be negative
[ -4 - ( -1 ) = -3 ] but it is also possible for the
difference to be positive [ -5 - ( -8 ) = 3 ]
Copyright copy by Houghton Mifflin Harcourt 16 All rights reserved
LESSON 34
Your Turn
1
-8 -7 -6 -5 -2 -1 0-4 -3
2 ( -35 ) = -7
2
-2 -1 0 1 2 3 4-4 -3
-3 ( -125 ) = 375
4 ( - 3 __ 4 ) ( - 4 __
7 ) ( - 2 __
3 ) = -
13 times 41 times 2 __________ 14 times 7 times 31
= - 1 times 1 times 2 _________ 1 times 7 times 1
= - 2 __ 7
5 ( - 2 __ 3 ) ( - 3 __
4 ) ( 4 __
5 ) = 2 times 31 times 41
__________ 13 times 41 times 5
= 2 times 1 times 1 _________ 1 times 1 times 5
= 2 __ 5
6 ( 2 __ 3 ) ( - 9 ___
10 ) ( 5 __
6 ) = -
12 times 93 times 51
____________ 13 times 210 times 63
= - 1 times 31 times 1 __________ 1 times 2 times 31
= - 1 __ 2
Guided Practice
1
-5 -2 -1 0-4 -3
5 ( - 2 __ 3 ) = 5 __
1 times ( - 2 __
3 )
= - 5 times 2 _____ 1 times 3
= - 10 ___ 3
= -3 1 __ 3
2
-1 -05 0-2 -15
3 ( - 1 __ 4 ) = 3 __
1 times - 1 __
4
= - 3 times 1 _____ 1 times 4
= - 3 __ 4
3
0 1 2-2 -1
-3 ( - 4 __ 7 ) = 3 __
1 times 4 __
7
= 3 times 4 _____ 1 times 7
= 12 ___ 7
= 1 5 __ 7
4
-2 -1 0 1 2 3 4-4 -3
- 3 __ 4 ( -4 ) = 3 __
4 times 4 __
1
= 3 times 41
______ 14 times 1
= 3 times 1 _____ 1 times 1
= 3 __ 1
= 3
5 4 ( -3 ) = -12
6 -18 ( 5 ) = -9
7 -2 ( -34 ) = 68
8 054 ( 8 ) = 432
9 -5 ( -12 ) = 6
10 -24 ( 3 ) = -72
11 1 __ 2 times 2 __
3 times 3 __
4 = ( 1 times 21
______ 12 times 3
) ( 3 __ 4 )
= ( 1 __ 3 ) ( 3 __
4 )
= 1
1 __ 3 times 3 __
4 1
= 1 __ 4
12 - 4 __ 7 ( -thinsp 3 __
5 ) ( - 7 __
3 ) = ( - 4 times 3 _____
7 times 5 ) ( - 7 __
3 )
= 12 ___ 35
( - 7 __ 3 )
= - 4
5 12 times 7 ______ 35 times 3
1
1
= - 4 times 1 _____ 5 times 1
= - 4 __ 5
13 ( - 1 __ 8 ) times 5 times 2 __
3 = ( - 1 __
8 ) times 5 __
1 times 2 __
3
= - 1 times 5 times 21
__________ 48 times 1 times 3
= - 1 times 5 times 1 _________ 4 times 1 times 3
= - 5 ___ 12
Copyright copy by Houghton Mifflin Harcourt 17 All rights reserved
14 ( - 2 __ 3
) ( 1 __ 2 ) ( - 6 __
7 ) = 2 times 1 times 62
__________ 13 times 21 times 7
= 1 times 1 times 2 _________ 1 times 1 times 7
= 2 __ 7
15 4 ( -350 ) = -14 or a $14 change in price
16 18 ( -100 ) = -1800 or a $1800 change
17 Sample answer Count the number of times there is
a negative sign If there are an even number of
negative signs then the final product will be positive
If there is an odd number of negative signs then the
final product will be negative
Independent Practice
18 a 6 ( -1998 ) Note that the change in her bank
account balance does not depend on the initial
amount
b 200 + 6 ( -1998 )
= 200 - 11988
= 8012 $8012
19 Sample answer Start at 0 then move 15 units to
the left (because 15 is negative in this case) 4 times
You are now on -6 Then because 4 is negative in
this case we want to move to the opposite of -6
which is 6
20 8 ( -3 1 __ 4 ) = -8 ( 13 ___
4 )
= - 1
8 __ 1 times 13 ___
4 1
= - 2 times 13 ______ 1 times 1
= - 26 ___ 1
-26 min At the same rate the watch will be
26 minutes behind after 8 weeks
21 3 ( -325 ) = -975 ft The change in depth is -975 ft
Therefore the submarine will be 975 below sea level
(below the surface)
22 5 + ( -3 ) ( 15 )
= 5 + ( -45 )
= 05 cups left
23 Matthew is incorrect Sample answer Matthew
should have said that multiplying by two negatives
is like multiplying the opposite of a positive twice
The opposite of a positive twice brings you back to
a positive
24 5 ( -15 ) = -75 min Therefore she will be late by
75 minutes or 1 hour and 15 minutes
25 Total score is
2 times ( 6 ) + 16 times ( 05 )
+ 7 times ( -05 ) + 2 times ( -15 )
= 12 + 8 - 35 - 3
= 20 - 65
= 135 pts
Focus on Higher Order Thinking
26 Temperature at 5 kilometers
= Temp at ground level + change in temp
= 12 + 5 ( -68 )
= 12 + ( -34 )
= -22degC
27 a b c d
+ + + +
+ + - +
+ - + +
- + + +
- - - +
- - + -
- + - -
+ - - -
28 If the product of two numbers is positive then the two
numbers must have the same sign either they are
both positive or both negative If the sum is negative
then at least one of the numbers must be negative
Therefore the two integers that add to -7 and multiply
to 12 must both be negative The negative paired
factors of 12 are -1 and -12 -2 and -6 and -3
and -4 Of those choices only -3 and -4 add to -7
LESSON 35
Your Turn
3 28 ___ -4
= - 28 ___ 4 = -07
4 -664 ______ -04
= 664 ____ 04
= 166
5 - 55 ___ 05
= - 55 ___ 5 = -11
6 -4256 _______ 112
= -38
The divers change in elevation was -38 feet
per minute
7 - 5 __
8 ___
- 6 __ 7 = - 5 __
8 divide - 6 __
7
= - 5 __ 8 times - 7 __
6
= 35 ___ 48
8 - 5 ___
12 ____
2 __ 3 = - 5 ___
12 divide 2 __
3
= - 5 ___ 12
times 3 __ 2
= - 15 ___ 24
= - 5 __ 8
Copyright copy by Houghton Mifflin Harcourt 18 All rights reserved
9 -4__5
___1__2 =-4__5divide1__
2
=-4__5times2__1
=-8__5
=-13__5
Guided Practice
1 072_____-09=-72___
9 =-08
2 -1__5
___7__5 =-1__
15times5
1__
7=-1times1_____
1times7=-1__7
3 56___-7=-56___7=-8
4 251____4 divide(-3__
8)=251____
4 times-8__
3
=-251times82________
14times3
=-251times2_______1times3
=-502____3
5 75____-1__5
=-75___1times5__
1=-75times5______
1times1=-375
6 -91____-13=91___
13=7
7 -3__7
___9__4 =-
13__7times4__93
=-1times4_____7times3
=-4___21
8 - 12____003
=-1200_____
3 =-400
9 =changeinwaterlevel_________________
changeindays
=-35L______4day
=-0875 L____day
or-0875Lperday
10 =totalchangeinprice_________________
changeindays
=-$4575________5day
=-$915perdayonaverage
11 totalchangeinaltitude___________________
numberofminutes
=-044mi________08min
=-44mi______8min
=-055mileperminute
12 FirstfindthesignofthenumeratorwhichisnegativeNextfindthesignofthedenominatorwhichisnegativeThereforethequotientwillbepositivebecausethenumeratoranddenominatorbothhavethesamesign
Independent Practice
13 5___-2__
8=-5__
1times8__
24
1=-5times4_____
1times1=-20
14 51__3divide(-11__
2)
=-3times5+1_________3 divide2times1+1_________
2
=-16___3divide3__
2
=-16___3times2__
3
=-16times2______3times3
=-32___9
15 -120_____-6 =120____
6 =20
16 -4__5
___-2__
3=
24__5times3__
21=2times3_____
5times1=6__
5
17 103divide(-103)=-103____1 times 1____
103
=-103times1________1times103
=-103____103
=-103____103
=-01
18 -04_____80
=-04___80
=-0005
19 1divide9__5=1__
1times5__
9=5__
9
20 -1___4 ___
23___24
=-1__
14times246
___23
=-1times6______1times23
=-6___23
21 -1035_______-23 =1035_____
23 =45
22 totalhours_____________numberofdays
= 21h______7days
=3 h____day
totaltimelost3 h____day
times3days=9hours
Alexusuallyruns21hoursperweeksodivideby7tofindthatheruns3hoursperdaySinceheisunabletorunfor3dayshistimeisdecreasedby9hoursor-9
23 totalchangeinyards
_________________numberofruns
=-4times15+3___________4 times1__
9
yd___run
=-763___4 times1__
91yd
___run
=-153__
4yd______
9runs
=-153__4times1__
9
yd___run
=-7__4or-13__
4yardsperrun
CopyrightcopybyHoughtonMifflinHarcourt 19 Allrightsreserved
DO NOT EDIT--Changes must be made through File info CorrectionKey=B
7_MCABESK207233_U1M03indd 19 103113 759 PM
24 -121degC + ( -78degC ) + ( -143degC ) + ( -72degC )
_____________________________________ 4
= 414degC ______ 4
= -1035degC per day
25 a total profit
_____________ number of days
= $1750
______ 7 days
= $250 per day
b $150
_____ day
times 7 days = $1050
c total change
_____________ number of days
= - $490
______ 7 days
= -$70 per day
26 total meters descended ___________________ number of seconds
= 996 m ______ 12 s
= 83 ms
27 When converting the division equation into a
multiplication problem he forgot to multiply by the
reciprocal and instead multiplied by the fraction in
the denominator The correct answer is given by
- 3 __
4 ___
4 __ 3
= - 3 __
4 times 3 __
4 = - 9 ___
16
28 -37 m _______ year times ( 2012 ndash 1995 ) years
= -37 m _______ year times 17 years
= -629 m
Focus on Higher Order Thinking
29 Sample answer The average change in temperature
per day would be given by -85 divide 15 if the
temperature were to drop of 85degF over 15 days
-85degF divide 15 d
= - 1785 ____ 315
degF __ d
= - 17 ___ 3 degF __
d or -5 2 __
3 degF __
d asymp -567 degF __
d
On average the temperature changed by -567degF
every day
30 Yes By definition the result of dividing an integer by
a non-zero integer is a rational number
31 Yes The result of dividing an integer by a non-zero
integer always results in a rational number by
definition
LESSON 36
Your Turn
1 Find the total commercial time
3 times 2 1 __ 2 = 7 1 __
2
Find the total entertainment time
30 - 7 1 __ 2 = 22 1 __
2
Find the length of each entertainment segment
22 1 __ 2 divide 4 = 5 5 __
8
Each entertainment segment is 5 5 __ 8 minutes long
2 Find the number of cups of sugar in the bag
454 divide 48 asymp 95
Find the number of 3 __ 4 -cup portions in the bag
95 divide 075 asymp 127
12 batches can be made from the bag of sugar
Find the cost of 1 batch
349 divide 12 asymp 029
The cost of the sugar is $029 per batch
3 Convert the percent to a decimal
12 3 __ 5 = 126
= 0126
Find the worth after 1 year
750 times 0126 = 945
750 + 945 = 8445
Find the worth after 2 years
8445 times 0126 asymp 10641
8445 + 10641 = 95091
Find the worth after 3 years
95091 times 0126 asymp 11981
95091 + 11981 = 107072
The stock is worth $107072
Guided Practice
1 45h times 3 1 __ 5 or 32 miles per hour = 144 miles
144 miles divide 3 3 __ 5 or 36 miles per hour = 4 hours
2 2568 inches times -002375 asymp -061 inches
2568 inches - 061 asymp 2507 inches
3 Sample answer Using a calculator to solve a
problem that involves complicated arithmetic can
help you avoid errors It can also help you to check
solutions to any problems you solved by hand
Independent Practice
4 Find the total weight
78 times 3 = 234
Find the weight each climber carries
234 divide 4 = 585
Each climber carries 585 kg
Copyright copy by Houghton Mifflin Harcourt 20 All rights reserved
5 Find the available width on the page
12 - 3 1 __ 2 = 8 1 __
2
Find half the width
8 1 __ 2 divide 2 = 4 1 __
4
He should put the picture 4 1 __ 4 inches from each side
of the page
6 Find the amount of cereal needed for all the children
11 times 1 __ 3 = 3 2 __
3
10 times 3 __ 4 = 7 1 __
2
3 2 __ 3 + 7 1 __
2 = 11 1 __
6
Compare the total needed with the amount in the
box
11 1 __ 6 lt 12
Yes there is enough Oaties for all the children The
amount needed is 11 1 __ 6 cups and that is less than the
amount in the box 12 cups
7 Find half of the distance that the referee walked
41 3 __ 4 divide 2 = 20 7 __
8
Find how far that distance is from the goal line
50 - 20 7 __ 8 = 29 1 __
8
The referee is 29 1 __ 8 feet from the nearest goal line
8 Donovanrsquos score was 39 ___ 50
= 78 Marcirsquos score was
( 78 + 10 ) = 88
9 Find the number Marci answered correctly
88 = 88 ____ 100
= 44 ___ 50
Find how many more that Marci answered than
Donovan
44 - 39 = 5
Marcie answered 5 more questions correctly than
Donovan
10 Sample answer Donovan got about 40 out of 50
questions right or about 80 Since Marci scored
10 more that is about 90 90 times 50 is 45 So
Marci answered about 45 - 40 or 5 more questions
correctly than Donovan
11 Yes -075 is a reasonable estimate
19 ___ 37
is about 1 __ 2 and 143 is about 15 and
15 times ( - 1 __ 2 ) = -075
12 Sample answer approximately -07343 Use a
calculator Divide -19 by 37 multiply the quotient by
143 then round the product
13 Sample answer Yes -07343 asymp - 075
Focus on Higher Order Thinking
14 Find the time of the descent
-79 9 ___ 10
divide ( -188 ) = 425
Find the time for the ascent
19 1 __ 8 - 1275 - 425 = 2 1 __
8
Find the distance of the ascent
-28 9 ___ 10
- ( -79 9 ___ 10
) = 51
Find the rate of the ascent
51 divide 2 1 __ 8 = 24
The diverrsquos rate of change in elevation during the
ascent was 24 ftmin
15 Sample answer
(1) Convert the mixed number 27 3 __ 5 to the decimal
276 find the sum of 276 and 159 then multiply
the result by 037
(2) Convert the mixed number 27 3 __ 5 to the decimal
276 Then use the Distributive Property so that
(276 + 159)037 = (276)(037) + (159)(037)
Multiply both 276 and 159 by 037 and add the
products I would use the first method because
there are fewer steps and so fewer chances to
make errors
16 Sample answer You need to know how many
gallons of paint you need to paint a wall Measure
the length and width of the wall with a yardstick
then find the area Use the calculator to divide the
area by the number of square feet a gallon of the
paint covers Round up rather than down to the
nearest gallon so you have enough paint
MODULE 3
Ready to Go On
1 4 1 __ 5 =
5 times 4 + 1 _________
5 = 21 ___
5
42
5 ⟌ _
210
_ -20
1 0
_ -1 0
0
42
Copyright copy by Houghton Mifflin Harcourt 21 All rights reserved
2 12 14 ___ 15
= 15 times 12 + 14
___________ 15
= 194 ____ 15
129 _ 3
15 ⟌ _
194000
_ -15
44
_ -30
14 0
_ -13 5
50 first 50
_ -45
50 second 50
Because the number 50 repeats during the division
process the answer is a repeating decimal
129 _ 3 or 12933
3 5 5 ___ 32
= 32 times 5 + 5
__________ 32
= 165 ____ 32
515625
32 ⟌ _
16500000
_ -160
5 0
_ -3 2
1 80
_ -1 60
200
_ -192
80
_ -64
160
_ -160
0
515625
4 45 + 71 = 116
5 5 1 __ 6 + ( -3 5 __
6 ) = 4
6+1 ____
6 -3 5 __
6
= 1 2 __ 6
= 1 1 __ 3
6 - 1 __ 8 -6 7 __
8 = - 1 __
8 + ( -6 7 __
8 )
= -6 8 __ 8
= -7
7 142 - ( -49 ) = 142 + 49
= 191
8 -4 ( 7 ___ 10
) = - 4 __ 1 times 7 ___
10
= - 24 times 7 _______ 1 times 105
= - 2 times 7 _____ 1 times 5
= - 14 ___ 5 or -2 4 __
5
9 -32 ( -56 ) ( 4 ) = 32 times 56 times 4
= 7168
10 - 19 ___ 2 divide 38 ___
7 = -
119 times 7 _______ 2 times 382
= - 1 times 7 _____ 2 times 2
= - 7 __ 4
11 -3201 _______ -33
= 3201 _____ 33
97
33 ⟌ _
3201
_ -297
23 1
_ -23 1
0
97
12 Add the initial stock price with the increase from the
second day
$8360 + $1535 = $9895
Convert the percent decrease to a decimal
-4 3 __ 4 = -475 or -00475
Multiply the price on the second day times the
percent decrease and then subtract the result from
the price on the second day to find the final stock
price
$9895 times -00475 asymp -$47
$9895 - $47 = $9425
The final stock price is $9425 Yes this is
reasonable price on day 1 asymp $85 price on day
2 asymp $100 So the price on day 3 asymp $95
13 Sample answer You can use negative numbers to
represent temperatures below zero or decreases in
prices
Copyright copy by Houghton Mifflin Harcourt 22 All rights reserved
MODULE 4 Ratios and Proportionality
Are You Ready
1 3 __ 4 divide 4 __
5 = 3 __
4 times 5 __
4
= 15 ___ 16
2 5 __ 9 divide 10 ___
11 = 5 __
9 times 11 ___
10
= 1
5 __ 9 times 11 ___
10 2
= 11 ___ 18
3 3 __ 8 divide 1 __
2 = 3 __
8 times 2 __
1
= 4
3 __ 8 times 2 __
1 1
= 3 __ 4
4 16 ___ 21
divide 8 __ 9 = 16 ___
21 times 9 __
8
=thinsp 2
7 16 ___ 21
times 9 __ 8 3
1
= 6 __ 7
5 B ( -4 1 )
6 C ( 3 0 )
7 D ( 5 4 )
8 E ( -2 -2 )
9 F ( 0 0 )
10 G ( 0 -4 )
LESSON 41
Your Turn
3 1 __ 6 acre divide ( 1 __
4 hour ) = 1 __
6 times 4 __
1
= 3
1 times 4 _____ 6 times 1
2
= 1 times 2 _____ 3 times 1
= 2 __ 3 acre per hour
4 3 cups divide ( 3 __ 4 cups ) = 3 __
1 divide 3 __
4
= 3 __ 1 times 4 __
3
= 1
3 times 4 _____ 1 times 3
1
= 1 times 4 _____ 1 times 1
= 4 cups
5 Jaylan 3 __ 4 divide 1 __
5 = 3 __
4 times 5 __
1 = 15 ___
4 = 3 3 __
4
Wanchen 2 __ 3 divide 1 __
6 = 2 ___
1 3 times 6
2 __
1 = 4 __
1 = 4
Jaylanrsquos unit rate is 3 3 __ 4 cups of water per cup of lime
juice Wanchenrsquos unit rate is 4 cups of water per cup
of lime juice Wanchenrsquos limeade has a weaker lime
flavor because 4 gt 3 3 __ 4 and the limeade with a
greater ratio of water to lime juice will have a weaker
flavor
Guided Practice
1
Distance (mi) 8 1 __ 2 17 25 1 __
2 34 42 1 __
2
Time (h) 1 __ 2 1 1 1 __
2 2 2 1 __
2
2 3 1 __ 2 miles divide ( 1 1 __
4 hours ) = 7 __
2 divide 5 __
4 mi ___ h
= 7 times 4 _____ 2 times 5
= 1 7 times 4 _____ 2 times 5
2
= 7 times 2 _____ 1 times 5
= 14 ___ 5 mi ___
h
= 2 4 __ 5 miles per hour
3 5 __ 8 page divide ( 2 __
3 minute ) = 5 __
8 times 3 __
2
= 15 ___ 16
page per minute
4 1 __ 6 foot divide ( 1 __
3 hour ) = 1 __
6 times 3 __
1
= 2 1 times 3 _____ 6 times 1
1
= 1 times 1 _____ 2 times 1
= 1 __ 2 foot per hour
5 5 __ 8 sq ft divide ( 1 __
4 hour ) = 5 __
8 times 4 __
1
= 2 5 times 4 _____ 8 times 1
1
= 5 times 1 _____ 2 times 1
= 5 __ 2 or 2 1 __
2 square feet per hour
Solutions KeyRatios and Proportional Relationships
UNIT
2
Copyright copy by Houghton Mifflin Harcourt 23 All rights reserved
6 240 milligrams divide ( 1 __ 3 pickle ) = 240 ____
1 divide 1 __
3
= 240 ____ 1 times 3 __
1
= 720 ____ 1
Brand Arsquos rate is 720 mg per pickle
325 milligrams divide ( 1 __ 2 pickle ) = 325 ____
1 divide 1 __
2
= 325 ____ 1 times 2 __
1
= 650 ____ 1
Brand Brsquos rate is 650 milligrams per pickle and is
therefore lower than Brand A
7 The unit rate for Ingredient C is
1 __ 4 cup divide ( 2 __
3 serving ) = 1 __
4 times 3 __
2
= 3 __ 8
cup _______
serving
The unit rate for Ingredient D is
1 __ 3 cup divide ( 3 __
4 serving ) = 1 __
3 times 4 __
3
= 4 __ 9
cup _______
serving
To compare 3 __ 8 to 4 __
9 find the least common
denominator of 8 and 9 so that 3 __ 8 = 27 ___
72 and 4 __
9 = 32 ___
72
Therefore ingredient Crsquos unit rate is lower
8 Divide the number in the numerator by the number
in the denominator Write the result with the units of
the rate
For example 1 mile ______
1 __ 2 hour
= 1 __
1 __ 2 = 2 miles per hour
Independent Practice
9 a The unit rate in dollars per hour for On Call is
$10 divide ( 35 hours ) = 10 ___ 35
$ __
h asymp $286 per hour
The unit rate in dollars per hour for Talk Time is
$125 divide ( 1 __ 2 hours ) = 125 ____
05 $ __
h asymp $250 per hour
b Talk Time offers the better deal because its rate in
dollars per hour is lower
c To convert dollars per minute to dollars per hour
multiply by 60
$005 divide ( 1 minute )
= 005 ____ 1
$ ____
min times 60 min ______
1 h
= $3 per hour
d $3 per hour is more expensive than either On Call
or Talk Time so it is not a better deal than either
one
10 a Sample answer 1 __ 2 cup dried fruit to 1 __
8 cup
sunflower seeds in a granola recipe
b The ratio would not change if the recipe were
tripled because both numbers in the ratio would
be multiplied by the same number and therefore
the ratio would still be equivalent to what it was
originally
c 1 __ 2 divide 1 __
8 = 1 ___
1 2 times 8
4 __
1 = 4 __
1 = 4
Sample answer 4 cups dried fruit per 1 cup
sunflower seeds
11 10 songs
____________ 2 commercials
= 5 songs ____________
1 commercials
12 a Terrancersquos rate
6 mi divide ( 1 __ 2 h ) = 6 __
1 times 2 __
1
= 12 miles per hour
Jessersquos rate
2 mi divide ( 15 min ) = 2 __ 1 divide 1 __
4
= 2 __ 1 times 4 __
1 mi ___ h
= 8 miles per hour
b Terrance
50 mi divide ( 12 mi ___ h ) = 50 ___
1 times 1 ___
12
= 50 ___ 12
h
= 4 1 __ 6 h
= 4 10 ___ 60
h
= 4 hours and 10 minutes
Jesse
50 mi divide ( 8 mi ___ h ) = 50 ___
1 times 1 __
8
= 50 ___ 8 h
= 6 1 __ 4 h
= 6 15 ___ 60
h
= 6 hours and 15 minutes
c 8 mi divide ( 45 min ) = 8 __ 1 divide 3 __
4
= 8 __ 1 times 4 __
3
= 32 ___ 3
= 10 2 __ 3 miles per hour
Sandrarsquos unit rate is greater than Jessersquos but
lower than Terrancersquos so she runs slower than
Terrance but faster than Jesse
13 1 ___ 10
h = 6 ___ 60
h = 6 min
300 words _________ 6 min
= 50 words per min
1 ___ 12
h = 5 ___ 60
h = 5 min
300 words _________ 5 min
= 60 words per min
Faster Eli typed 50 words per minute in his first test
and 60 words per minute in his second test
Copyright copy by Houghton Mifflin Harcourt 24 All rights reserved
Focus on Higher Order Thinking
14 a For the 10-pack of 21 ounce bars
$1537 divide 10 bars asymp $154 per bar
For the 12-pack of 14 ounce bars
$1535 divide 12 bars asymp $128 per bar
The 12-pack has the better price per bar
b For the 10-pack
$1537 divide ( 10 times 21 oz ) = 1537 divide 21
asymp $073 per ounce
For the 12-pack
$1535 divide ( 12 times 14 oz ) = 1535 divide 168
asymp $091 per ounce
The 10-pack has a better price per ounce
c Sample answer Since I always eat them one bar
at a time the 12-pack is the better choice
15 Yes Half a room in half a day corresponds to a unit
rate of 1 __ 2 room divide ( 1 __
2 day ) = 1 room _____
day so at the same
rate the painter could paint 7 rooms in 7 days
16 Sample answer Take the reciprocal of the rate For
example a rate of 7 gallons per hour is equal to
1 hour per 7 gallons
LESSON 42
Your Turn
3 No the rates are not equal and therefore her speed
was not constant
4 Since the ratio of students to adults is constant the
relationship between them is proportional
students ________ adults
= 12 ___ 1 = 36 ___
3 = 60 ___
5 = 12 students per adult
If s = the number of students and a = the number
of adults then a = 1 ___ 12
s or s = 12a
Guided Practice
1 45 ___ 1 = 45 90 ___
2 = 45 135 ____
3 = 45 180 ____
4 = 45
The relationship is proportional
2 k = y __ x = 10 ___
2 = 5 y = 5x
3 k = y __ x = 2 __
8 = 1 __
4 y = 1 __
4 x
4 With the equation y = kx where k is the constant
of proportionality
Independent Practice
5 k = y __ x = 74 ___
4 = 1850 y = 1850x
6 $1099
_______ 05 days
= $2198 per day
7 Rent-All because it has the lowest price per day
($1850)
8 100 ft _____ 08 s
= 1000 _____ 8 ft __ s = 125 ft __ s
500 ft _____ 31 s
= 5000 _____ 31
ft __ s asymp 1613 ft __ s
1875 ft ______ 15 s
= 1875 ______ 15
ft __ s asymp 125 ft __ s
No Emtiaz assumed the relationship is proportional
but it is not The rate of change is not constant and
so his answer is not reasonable
9 $3125
______ 5 h
= $625 per hour and $5000
______ 8 h
= $625 per
hour Because the two unit rates are the same the
relationship between charge and time is proportional
10 The constant rate of change in this context means
that Steven charges $625 per hour
11 y = $625x where x is the number of hours Steven
babysits and y is the amount Steven charges
12 y = $625 ( 3 ) = $1875
13 300 ft _____ 2 min
= 6750
_____ 45
= 150 feet per minute
150 ft _____ min
times 60 min ______ 1 h
= 9000 feet per hour
14 y = 150x
15 Sample answer Feet per minute A submarine may
stay submerged for hours but it would not dive for
hours
Focus on Higher Order Thinking
16 Yes because there is a proportional relationship
so the distance and the time would increase by the
same factor
17 Sample answer Yes Even though the rates in the
table are not constant per ear of corn due to
rounding there is a constant rate for every 3 ears
of corn
LESSON 43
Your Turn
1 No because 11 ___ 1 ne 16 ___
2 Also the line drawn through
the points does not go through the origin
5 a The point ( 4 60 ) represents that the bicyclist can
ride a distance 60 miles in 4 hours
b k = 60 mi _____ 4 h
= 15 mi ___ h
c y = 15x where x is time in hours and y is
distance in miles
Guided Practice
1
Time (h) 3 5 9 10
Pages 195 325 585 650
Proportional the rate is a constant 65 pages
per hour
2
Time (h) 2 3 5 8
Earnings 15 2250 3750 60
Proportional the rate of is a constant $750 per hour
Copyright copy by Houghton Mifflin Harcourt 25 All rights reserved
3 Not proportional the relationship is linear but a line
drawn connecting the points will not pass through
the origin of ( 0 0 )
4 Proportional a line can be drawn that passes
through the points and also the origin of ( 0 0 )
5 k = 28 ft ____ 8 s
= 7 __ 2 ft __ s = 35 ft __ s y = 7 __
2 x or y = 35x where
x = time in seconds and y = height in feet
6 k = $2 ______
8 items = 1 __
4
$ _____
items = 025
$ _____
items so y = 1 __
4 x or
y = 025x where x = number of items and
y = cost in dollars
7 The graph is a straight line passing through the
origin
Independent Practice
8 It is the distance ( 0 miles ) that each horse runs in
0 minutes
9 Horse A runs 1 mile in 4 minutes
Horse B runs 1 mile in 25 minutes
10 For Horse A y = 1 __ 4 x
For Horse B y = 1 ___ 25
x or 2 __ 5 x
11 If x is time in minutes and y is distance in miles in
12 minutes Horse A will run 3 miles or 1 __ 4 ( 12 ) = 3
and Horse B will run 48 miles or 2 __ 5 ( 12 ) = 24 ___
5 = 48
12 Students may draw any straight line with a slope
steeper than 2 __ 5 that starts at the origin of ( 0 0 ) An
example is given below
2
2
4
6
8
10
4 6 8 10Time (min)
Dis
tanc
e (m
i)
A
B
O
13 Yes if the train is traveling at a constant speed the
ratio of miles traveled to time in hours will be
constant and therefore a graph comparing miles to
hours will form a straight line that passes through
the origin of ( 0 0 )
14 Sample answer When comparing relationships that
may be easier to observe on a graph than in an
equation
15 a
2
8
16
24
32
40
4 6 8 10DVDs
Cost
($)
O
b Sample answer The graph will pass through the
point ( 4 20 ) This point shows that four DVDs will
cost $20
16 The graph passes through the point ( 4 8 ) so
Glenda swam 8 feet in 4 seconds
17 Yes The graph is linear and passes through the
origin and therefore the rate of distance to time is
proportional at each point on the line
18 k = 8 ft ___ 4 s
= 2 ft __ s so y = 2x where x is time in
seconds and y is distance swam in feet It would
take 22 minutes to swim 1 __ 2 mile at this rate
Focus on Higher Order Thinking
19 Divide the second coordinate by the first to find the
constant of proportionality k Substitute the value of
k into the equation y = kx Then choose a value for x
and solve for y to find the ordered pair
20 Car 3 is not traveling at a constant speed
because 65 ___ 1 ne 85 ___
2
21 Since Car 4 is traveling at twice the speed it will
travel twice the distance as Car 2 in the same
amount of time Therefore the values in Car 4rsquos
distance column will be twice that shown in Car 2rsquos
distance column
MODULE 4
Ready to Go On
1 $140
_____ 18 ft 2
= $778 per square foot
2 $299
_____ 14 lb
asymp $021 per pound
3 $56 ______
25 gal = $224 per gallon
$3205
______ 15 gal
asymp $214 per gallon this is the better deal
4 $160
_____ 5 g
= $3200 per gram this is the better deal
$315
_____ 9 g
asymp $3500 per gram
5 No The ratio of dollars earned to lawns mowed is
not constant 15 ___ 1 ne 48 ___
3
Copyright copy by Houghton Mifflin Harcourt 26 All rights reserved
6 k = $9
___ 8euro
= $27 ____
24euro = 9 __
8 $ __
euro or 1125
$ __
euro So y = 9 __
8 x or
y = 1125x where x equals the number of euros
and y equals their value in dollars
7 The graph passes through the point ( 2 5 )
so k = 5 __ 2 servings
_______ pt
or k = 25 servings
_______ pt
Therefore
y = 5 __ 2
x or y = 25x where x equals the number
of pints and y equals the number of servings
8 The new graph will pass through the points ( 0 0 ) and ( 3 2 )
2
2
4
6
8
10
4 6 8 10Pints
Serv
ings
Frozen Yogurt
O
Therefore y = 2 __ 3 x where x equals the number of
pints and y equals the number of servings
9 Sample answer Compare corresponding values of
the variables to determine whether there is a
constant rate
Copyright copy by Houghton Mifflin Harcourt 27 All rights reserved
MODULE 5 Proportions and Percent
Are You Ready
1 22 = 22 ____ 100
= 022
2 75 = 75 ____ 100
= 075
3 6 = 6 ____ 100
= 006
4 189 = 100 + 89
= 100 ____ 100
+ 89 ____ 100
= 1 + 089
= 189
5 059 = 59
6 098 = 98
7 002 = 2
8 133 = 133
9 64
_ timesthinsp05
320
32
10 30
_ timesthinsp007
210
21
11 160
_ timesthinsp015
800
_ +1600
2400
24
12 62
_ timesthinsp032
124
_ +thinsp1860
1984
1984
13 4
_ timesthinsp12
8
_ +thinsp40
48
48
14 1000
_ timesthinsp006
6000
60
LESSON 51
Your Turn
2 x = ( $64 - 52 )
__________ $52
x = $12
____ $52
asymp 23
4 x = ( 18 - 12 )
________ 18
x = 6 ___ 18
asymp 33
5 x = ( 16 - 10 )
________ 16
x = 6 ___ 16
= 375
8 010 times $499 = $4990
$499 + $4990 = $54890
9 030 times $499 = $14970
$499 - $14970 = $34930
Guided Practice
1 x = ( $8 - $5 )
_________ $5
x = $3
___ $5
= 60
2 x = ( 30 - 20 )
_________ 20
x = 10 ___ 20
= 50
3 x = ( 150 - 86 )
__________ 86
x = 64 ___ 86
asymp 74
4 x = ( $389 - $349 )
______________ $349
x = $040
_____ $349
asymp 11
5 x = ( 14 - 13 )
________ 13
x = 1 ___ 13
asymp 8
6 x = ( 16 - 5 )
________ 5
x = 11 ___ 5 = 220
7 x = ( 64 - 36 )
_________ 36
x = 28 ___ 36
asymp 78
8 x = ( 80 - 64 )
_________ 80
x = 16 ___ 80
= 20
9 x = ( 95 - 68 )
_________ 95
x = 27 ___ 95
asymp 28
Copyright copy by Houghton Mifflin Harcourt 28 All rights reserved
10 x=( 90-45)_________
90
x=45___90
=50
11 x=( 145-132)__________
145
x=13____145
asymp9
12 x=( 64-21)_________
64
x=43___64
asymp67
13 x=( 16-0)________
16
x=16___16
=100
14 x=( 3-1__
2)_______
3
x=21__
2___
3 asymp83
15 010times$900=$090 $900+$090=$990
16 025times48=12 48-12=36cookies
17 020times340=68 $340-68=272pages
18 050times28=14 28+14=42members
19 004times$29000=$1160 $29000-$1160=$27840
20 130times810=1053 810+1053=1863songs
21 030times20=6 20+6=26miles
22 Dividetheamountofchangeinthequantitybytheoriginalamountthenexpresstheanswerasapercent
Independent Practice23
ItemOriginal
PriceNew Price
Percent Change
Increase or
DecreaseBike $110 $96 asympthinsp13 Decrease
Scooter $45 $56 asympthinsp24 Increase
TennisRacket $79 $8295 5 Increase
Skis $580 $435 25 Decrease
24 a 55
x=( 8-3)_______
8 =5__
8=625
x=( 12-7)________
12 =5___
12asymp417
Theamountofchangeisthesamebutthepercentofchangeislessfrom2010to2011
b Changewasgreatestbetween2009and2010
x=( 12-3)________
3
x=9__3=300increase
25 a Amountofchange=( 5-4)=1
Percentdecrease=1__5=20
b $100_____5 =$020each$100_____
4 =$025each
Amountofchange=$025-$020=$005
Percentincrease=$005_____$020
=25
26 Percenterror=( 136-133)___________
136 times100
=03____136
times100asymp2
Focus on Higher Order Thinking
27 a Theyhavethesame$100+$10=$110and$100+10( $100)=$110
b SylviahasmoreLeroihas$110+$10=$120andSylviahas$110+10( $110)=$121
c BecauseSylviawillhavemoreafterthesecondadditionaldepositandshewillbedepositingincreasingamountsshewillalwayshavemoreinheraccount
28 Thefinalamountisalways0becausea100decreaseofanyamountwouldbe0
29 NoOnlythefirstwithdrawalis$10Eachwithdrawalafterthatislessthan$10becauseitis10oftheremainingbalanceTherewillbemoneyleftafter10withdrawals
LESSON 52
Your Turn
2 a 1c+01c11c
b s=11times$28=$3080
3 a 200
b 1c+2c3c
5 a
1b - 024b
1b024b
b 1b-024b=076b
6 a 1p-005p095p
b 095p=$1425
CopyrightcopybyHoughtonMifflinHarcourt 29 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U2M05indd 29 103113 214 AM
Guided Practice
1 a 035s
b 1s + 035s 135s
c 135 times $3200 = $4320
d 035 times $3200 = $1120
Item Price Markup MarkupRetail
Price
2 Hat $18 15 $270 $2070
3 Book $2250 42 $945 $3195
4 Shirt $3375 75 $2531 $5906
5 Shoes $7499 33 $2475 $9974
6 Clock $4860 100 $4860 $9720
7 Painting $18500 125 $23125 $41625
8 $4500 - 022 ( $4500 ) = $3510
9 $8900 - 033 ( $8900 ) = $5963
10 $2399 - 044 ( $2399 ) = $1343
11 $27999 - 075 ( $27999 ) = $7000
12 Write the percent of markdown as a decimal
subtract the product of this decimal and the regular
price from the regular price
Independent Practice
13 a 046b
b 1b - 046b 054b
c 054 times $2900 = $1566
d 046 times $2900 = $1334
14 Regular Price $329
Sale Price $201
Regular Price $419
Sale Price $245
Regular Price $279
Sale Price $115
Regular Price $309
Sale Price $272
Regular Price $377
Sale Price $224
15 a Sample answer original price $100 final price
$050
b Sample answer original price $100 final price
$9950
c Sample answer original price $100 final price
$350
16 p = 127 ( $7400 ) = $9398
s = 127 ( $4800 ) = $6096
j = 127 ( $32500 ) = $41275
2 ( 9398 ) + 3 ( $6096 ) + $41275 = $78359
17 Either buy 3 get one free or 1 __ 4 off Either case would
result in a discount of 25 which is better than 20
Focus on Higher Order Thinking
18 No she is taking a loss Her cost for the tea is t so
the retail price is 12t The discounted price is
08 ( 12t ) or 096t which is less than t
19 No first change 201 decrease second change
251 increase The second percent change is
greater
20 Rafael can purchase the coat after 11 or 12 weeks
after 11 weeks the price is $10932 after 12 weeks
the price is $10385 and after that Danielle donates
the coat
LESSON 53
Your Turn
1 005 times $2000 = $100 $100 + $2000 = $2100
3 005 times $40000 = $2000
$2000 times 4 years = $8000
$40000 + $8000 = $48000
4 Commission $4500 times 00375 = $16875
Total $2200 + $16875 = $236875
Guided Practice
1 005 times $3000 = $150
2 015 times $7000 = $1050
3 0004 times $10000 = $040
4 15 times $2200 = $3300
5 001 times $8000 = $080
6 20 times $500 = $1000
7 a 007 times $4399 = $308
b $4399 + $308 = $4707
8 115 times $7550 = $8683
9 007 times $2000 = $140
$140 times 5 years = $700
10 003 times $550 = $1650
$1650 times 10 years = $165
$550 + $165 = $715
11 a 090 times $20 = $18
b 1085 times $18 = $1953
12 020 times $2999 = $600 tip
00625 times $2999 = $187 tax
$2999 + $600 + $187 = $3786 total
13 Write the tax rate as a decimal Then multiply the
decimal by the price of the item and add the result
to the price
Independent Practice
14 $3275 + $3988 = $7263 total meal cost
014 times $7263 = $1017 tip
$7263 + $1017 = $8280 total with tip
15 $7865 times 015 = $1180 meal discount
$7865 times 020 = $1573 tip
$7865 + $1573 - $1180 = $8258 total
16 $125 times 235 = $29375 retail ring cost
0075 times $29375 = $2203 tax
$29375 + $2203 = $31578 total with tax
Copyright copy by Houghton Mifflin Harcourt 30 All rights reserved
17 $7999 times 012 = $960 discount
$7999 - $960 = $7039 price before tax
$7039 times 10675 = $7514 total with tax
18 4 times $999 times 020 = $799 discount
4 times $999 - $799 = $3197 price before tax
$3197 times 10675 = $3413 total with tax
19 $4500 + 00725 = $32625 commission
$750 + $32625 = $107625 total income
20 $700 times 0055 = $3850 commission
$475 + $3850 = $51350 total income
21 a Multiply Sandrarsquos height by 010 and add the
product to 4 to get Pablorsquos height Then multiply
Pablorsquos height by 008 and add the product to
Pablorsquos height to get Michaelarsquos height
b Using 48 inches for 4 feet
48 inches times 01 = 48 inches so Pablorsquos height is
53 inches or 4 feet 5 inches to the nearest inch
53 inches times 008 = 42 inches so Michaelarsquos
height is 57 inches or 4 feet 9 inches to the
nearest inch
22 a $4998 times 05 = $2499 50 discount
$2499 - $1000 = $1499 $10 discount
b $4998 - $1000 = $3998 $10 discount
$3998 times 05 = $1999 50 discount
23 a $95 times 09 = $8550 discounted camera
$8550 + $1599 = $10149 total
b $1599 times 09 = $1439 discounted battery
$95 + $1439 = $10939 total
c Eric should apply the discount to the digital
camera he can save $8
d $10149 times 008 = $812 tax
$10149 + $812 = $10961 total
24 a Store 1 $22 divide 2 = $11
Store 2 $1299 times 09 = $1169
Store 1 charges $11 per shirt and Store 2
charges $1169 Therefore I would save
$069 per shirt at Store 1
b Store 3 $2098 times 045 = $944
Yes It is selling shirts at $944
Focus on Higher Order Thinking
25 Marcus should choose the option that pays $2400
plus 3 of sales He would make $2550 to $2700
per month The other option would pay only $1775
to $2050 per month
26 Percent error = ǀ 132 - 137 ǀ
____________ 137
times 100 = 05 ____ 137
asymp 36
MODULE 5
Ready to Go On
1 x = ( 63 - 36 )
_________ 36
x = 27 ___ 36
= 75 increase
2 x = ( 50 - 35 )
_________ 50
x = 15 ___ 50
= 30 decrease
3 x = ( 72 - 40 )
_________ 40
x = 32 ___ 40
= 80 increase
4 x = ( 92 - 69 )
_________ 92
x = 23 ___ 92
= 25 decrease
5 $60 times 015 = $9
$60 + $9 = $69
6 $32 times 0125 = $4
$32 + $4 = $36
7 $50 times 022 = $11
$50 - $11 = $39
8 $125 times 030 = $3750
$12500 - $3750 = $8750
9 $4800 times 0065 = $312 commission
$325 + $312 = $637 total income
10 $5310
______ $1735
asymp 31
11 Find the amount per hour that Priya makes if she
makes 20 more than James
$700 times 020 = $140
$700 + $140 = $840
Next find the amount Slobhan makes if he makes
5 less than Priya
$840 times 005 = $042
$840 - $042 = $798
Slobhan makes $798 per hour
12 Both the 6 tax and the 20 tip are applied to the
initial cost of the meal so the two percents can be
added together and multiplied by the cost
$45 times 026 = $1170
$45 + $1170 = $5670
The total cost of the meal is $5670
13 Sample answer sales tax increase discount
decrease tip increase
Copyright copy by Houghton Mifflin Harcourt 31 All rights reserved
MODULE 6 Expressions and Equations
Are You Ready
1 5 + x
2 11 - n
3 -9 ___ y
4 2x - 13
5 2x + 3
= 2 ( 3 ) + 3
= 6 + 3
= 9
6 -4x + 7
= -4 ( 1 ) + 7
= -4 + 7
= 11
7 15x - 25
= 15 ( 3 ) - 25
= 45 - 25
= 2
8 04x + 61
= 04 ( -5 ) + 61
= -20 + 61
= 41
9 2 __ 3 x - 12
= 2 __ 3
( 18 ) - 12
= 2 __ 3
times ( 18 ___ 1 ) - 12
= 36 ___ 3 - 12
= 0
10 - 5 __ 8
x + 10
= - 5 __ 8 ( -8 ) + 10
= - 5 __ 8 times- 8 __
1 + 10
= - 5 ___ 1 8
times- 8 1 __
1 + 10
= - 5 __ 1 times- 1 __
1 + 10
= 5 + 10
= 15
11 1 __ 2 divide 1 __
4
= 1 times 4 _____ 2 times 1
= 1 times 4 2 ______
1 2 times 1
= 1 times 2 _____ 1 times 1
= 2
12 3 __ 8 divide 13 ___
16
= 3 __ 8 times 16 ___
13
= 3 times 16 2 _______
1 8 times 13
= 3 times 2 ______ 1 times 13
= 6 ___ 13
13 2 __ 5 divide 14 ___
15
= 2 __ 5 times 15 ___
14
= 1 2 times 15
3 ________
1 5 times 14 7
= 1 times 3 _____ 1 times 7
= 3 __ 7
14 4 __ 9 divide 16 ___
27
= 4 __ 9 times 27 ___
16
= 1 4 times 27
3 ________
1 9 times 16 4
= 1 times 3 _____ 1 times 4
= 3 __ 4
LESSON 61
Your Turn
2 ( 3x + 1 __ 2 ) + ( 7x - 4 1 __
2 )
= 3x + 7x + 1 __ 2 - 4 1 __
2
= 10x - 4
3 ( -025x - 3 ) - ( 15x + 14 ) = -025x - 3 - 15x - 14
= -175x - 44
4 02(3b - 15c) + 6c
= 06b - 3c + 6c
= 06b + 3c
5 2 __ 3 (6e + 9f - 21g) - 7f
= 4e + 6f - 14g - 7f
= 4e - f - 14g
6 5x - 3(x - 2) - x
= 5x - 3x + 6 - x
= x + 6
7 83 + 34y - 05(12y - 7)
= 83 + 34y - 6y + 35
= 118 - 26y
Solutions KeyExpressions Equations and Inequalities
UNIT
3
Copyright copy by Houghton Mifflin Harcourt 32 All rights reserved
Guided Practice
1 baseballs 14 + (12)n tennis balls 23 + (16)n
14 + 12n + 23 + 16n
14 + 23 + 12n + 16n
37 + 28n
So the total number of baseballs and tennis balls is
37 + 28n
2 37 + 28n
37 + 28 ( 9 )
= 37 + 252
= 289
3 14 + 5(x + 3) - 7x = 14 + 5x + 15 - 7x
= 29 - 2x
4 3 ( t - 4 ) - 8 ( 2 - 3t ) = 3t - 12 - 16 + 24t
= 27t - 28
5 63c - 2 ( 15c + 41 ) = 63c - 3c - 82
= 33c - 82
6 9 + 1 __ 2 ( 7n - 26 ) - 8n = 9 + 35n - 13 - 8n
= -4 - 4 1 __ 2 n
7 2x + 12
2 ( x + 6 )
8 12x + 24
12 ( x + 2 )
9 7x + 35
7 ( x + 5 )
10 You multiply numbers or expressions to produce a
product You factor a product into the numbers or
expressions that were multiplied to produce it
Independent Practice
11 Let d = number of days
Fee for 15 food booths 15 ( 100 + 5d ) Fee for 20 game booths fee 20 ( 50 + 7d ) Amount the company is paid for the booths
15 ( 100 + 5d ) + 20 ( 50 + 7d ) = 15 ( 100 ) + 15 ( 5d ) + 20 ( 50 ) + 20 ( 7d )
= 1500 + 75d + 1000 + 140d
= 1500 + 1000 + 75d + 140d
= 2500 + 215d
12 New length 96 + l
New width 60 + w
Perimeter of new pattern
2(96 + l) + 2(60 + w)
=2(96) + 2l + 2(60) + 2w
192 + 2l + 120 + 2w
192 + 120 + 2l + 2w
312 + 2l + 2w
13 Width 3
Length 1 x-tile and 2 +1-tiles
Factors 3 and x + 2
Product 3 ( x + 2 ) = 3x + 6
14 Width 4
Length 2 x-tiles and 1 -1-tile
Factors 4 and 2x - 1
Product 4 ( 2x - 1 ) = 8x - 4
15 The area is the product of the length and width
( 6 times 9 ) It is also the sum of the areas of the
rectangles separated by the dashed line ( 6 times 5
and 6 times 4 ) So 6 ( 9 ) = 6 ( 5 ) + 6 ( 4 )
16 Perimeter of triangle ( x + 3 ) + ( 2x + 4 ) +
6x = ( x + 3 ) + ( 2x + 4 ) +
6x = 3x + 7 +
-3x = _ -3x
3x = 7 +
_ -7 = _ -7
3x - 7 =
The length of the side is 3x - 7
17 Perimeter of rectangle 2 ( 3x - 3 ) + 2 ( )
10x + 6 = 2 ( 3x - 3 ) + 2 ( )
10x + 6 = 6x - 6 + 2
_ -6x = _ -6x
4x + 6 = - 6 + 2
_ + 6 = _ + 6
4x + 12 = 2
( 4x + 12 ) divide 2 = ( 2 ) divide 2
2x + 6 =
The length of the side is 2x + 6
18 a P = 2l + 2w
Perimeter of tennis court T
2(2x + 6) + 2(x)
= 4x + 12 + 2x
= 6x + 12
Perimeter of basketball court B
2(3x - 14) + 2( 1 __ 2 x + 32)
= 6x - 28 + x + 64
= 7x + 36
b (7x + 36) - (6x + 12)
= 7x + 36 - 6x - 12
= x + 24
c Find the length of tennis court
Let x = 36
2x + 6 = 2 ( 36 ) + 6
= 72 + 6
= 78
Find the width of the basketball court
Let x = 36
1 __ 2 x + 32 = 1 __
2 ( 36 ) + 32
= 18 + 32
= 50
Find the length of the basketball court
Let x = 36
3x - 14 = 3 ( 36 ) - 14
= 108 - 14
= 94
The tennis court is 36 ft by 78 ft The basketball
court is 50 ft by 94 ft
Focus on Higher Order Thinking
19 Find the area of each small square and rectangle
( x ) ( x ) = x 2
( x ) 1 = x
( 1 ) 1 = 1
Copyright copy by Houghton Mifflin Harcourt 33 All rights reserved
x
x
1
11
1 1
x2 x x x
x 1 1 1x 1 1 1
Area =
x 2 + x + x + x + x + x + 1 + 1 + 1 + 1 + 1 + 1
= x 2 + 5x + 6
( x + 3 ) ( x + 2 ) = x 2 + 5x + 6
20 Agree To find 58 times 23 let 23 = 3 + 20 Then find
the product 58 ( 3 + 20 ) First step 58 ( 3 ) = 174
Second step 58 ( 20 ) = 1160 Third step 174 +
1160 = 1334 So 58 ( 23 ) = 58 ( 3 ) + 58 ( 20 )
21 ( 1 ) Think of 997 as 1000 - 3 So 8 times 997 = 8 ( 1000 - 3 ) By the Distributive Property
8 ( 1000 - 3 ) = 8000 - 24 = 7976
( 2 ) Think of 997 as 900 + 90 + 7 By the Distributive
Property 8 ( 900 + 90 + 7 ) = 7200 + 720 + 56 =
7976
LESSON 62
Your Turn
1 49 + z = -9
_ -49 _ -49
z = -139
2 r - 171 = -48
_ +171 _ +171
r = 123
3 -3c = 36
-3c ____ -3
= 36 ___ -3
c = -12
5 x - 15 = 525
_ +15 _ +15
x = 675
The initial elevation of the plane is 675 miles
6 x ___ 35
= -12
x ___ 35
( 35 ) = -12 ( 35 )
x = -42
The decrease in the value of the stock was $420
7 25x = 75
25x ____ 25
= 75 ___ 25
x = 3
The power was restored in 3 hours
Guided Practice
1 Let x represent the number of degrees warmer the
average temperature is in Nov than in Jan
x + ( -134 ) = -17 or x - 134 = -17
x - 134 = -17
_ +134 _ +134
x = 117
The average temperature in November is 117degF
warmer
2 Let x represent the number of days it takes the
average temperature to decrease by 9degF
-1 1 __ 2 x = -9
( - 2 __ 3 ) ( - 3 __
2 x ) = ( - 2 __
3 ) ( -9 )
x = 18 ___ 3
x = 6
It took 6 days for the temperature to decrease by 9degF
3 -2x = 34
-2x ____ -2
= 34 ___ -2
x = -17
4 y - 35 = -21
_ + 35 _ + 35
y = 14
y = 14
5 2 __ 3 z = -6
( 3 __ 2 ) 2z ___
3 = ( 3 __
2 ) ( -6 )
z = -9
6 Sample answer It helps me describe the problem
precisely and solve it using inverse operations
Independent Practice
7 Let x equal the elevation of Mt Everest
x - 870737 = 203215
_ +870737 _ +870 737
x = 2902887
The elevation of Mt Everest is 2902887 ft
8 Let x equal the number of feet Liam descended
2825131 - x = 2320106
_ -2825131 _ -2825131
-x = - 505025
x = 505025
Liam descended 505025 ft
His change in elevation was -505025 ft
9 Let x equal the elevation of Mt Kenya
2825131 - x = 1119421
_ -2825131 _ -2825131
-x = -1705710
x = 1705710
The elevation of Mt Kenya is 170571 ft
10 Find the change in elevation
1250 - 935 = 315
Use an equation
Let x = the number of minutes the balloon
descends
( -22 1 __ 2 ) x = -315
( - 45 ___ 2 ) x = -315
( - 2 ___ 45
) ( - 45 ___ 2 ) x = -315 ( - 2 ___
45 )
x = 14
It will take the balloon 14 minutes to descend
11 Find the change in elevation
4106 - 3205 = 901
Use an equation to find the rate of descent
Copyright copy by Houghton Mifflin Harcourt 34 All rights reserved
Let x = rate of descent
34x = 901
34x ____ 34
= 901 ____ 34
x = 265 = 26 1 __ 2
The rate of descent was 26 1 __ 2 feet per minute
12 Let x = the number of degrees warmer Montanarsquos
average temperature is than Minnesotarsquos
- 25 + x = -07
_ + 25 _ + 25
x = 18
Montanarsquos average 3-month temperature is 18degC
warmer than Minnesotarsquos
13 Let x = the number of degrees warmer Floridarsquos
average temperature is than Montanarsquos
181 - x = -07
_ - 181 _ -181
-x = -188
x = 188
Floridarsquos average 3-month temperature is 188degC
warmer than Montanarsquos
14 Let x = the number of degrees the average
temperature in Texas would have to change
125 + x = 181
_ -125 _ -125
x = 56
It would have to increase by 56degC
15 Let x = the number of yards the team must get on
their next play
-26 1 __ 3
+ x = 10
+26 1 __ 3
______
+26 1 __ 3
______
x = 36 1 __ 3
The team needs to get 36 1 __ 3 yards on their next play
16 Let x = the number of seconds
( -2 1 __ 2 ) x = -156
( -25 ) x = -156
( -25 _____ -25
) x = -156 ______ -25
x = 624
It takes the diver 624 seconds to reach -156 feet
17 Sample answer The elevation is the product of the
rate and the time
18 Let x = the total amount withdrawn
x __ 5 = 455
( 5 ) x __ 5 = 455 ( 5 )
x = 2275
The total amount she withdrew was $22750
Sample answer
$4550 asymp $50 and $50 times 5 = $250 which is close
to $22750
Focus on Higher Order Thinking
19 ( 1 ) The elevations of the diver and the reef both are
below sea level
( 2 ) The change in the planersquos elevation the plane
descends the plane is moving from a higher to a
lower elevation
20 -4x = -48
( -4x ____ -4
) = -48 _____ -4
x = 12
- 1 __ 4 x = -48
( -4 ) ( - 1 __ 4 ) x = -48 ( -4 )
x = 192
192 ____ 12
= 16
In the first case -4x = -48 you divide both sides
by -4 In the second - 1 __ 4 x = -48 you multiply
both sides by -4 The second solution (192) is
16 times the first (12)
21 Add the deposits and the withdrawals Let x repre-
sent the amount of the initial deposit Write and
solve the equation x + deposits - withdrawals =
$21085
LESSON 63
Your Turn
4 Let x represent the number of video games Billy
purchased
Original balance on gift card $150
Cost for x video games $35 middot x
Final balance on gift card $45
Original balance minus $35 times number of games equals $45
darr darr darr darr darr darr darr $150 - $35 middot x = $45
Equation 150 - 35x = 45
5 Sample answer You order x pounds of coffee from
Guatemala at $10 per pound and it costs $40 to
ship the order How many pounds can you order so
that the total cost is $100
Guided Practice
1
+ + ++ ++
+++ + +
+++
2
----
+ ++ ++
- - -
Copyright copy by Houghton Mifflin Harcourt 35 All rights reserved
3 Let a represent the number of adults that attend
Ticket cost for 1 child = $6
Ticket cost for a adults = $9 middot a
Total cost for movie = $78
cost for child plus $9 times number of adults equals $78
darr darr darr darr darr darr darr $6 + $9 middot a = $78
Equation 6 + 9a = 78
4 x is the solution of the problem
2x is the quantity you are looking for multiplied by 2
+ 10 means 10 is added to 2x
= 16 means the result is 16
5 Sample answer A department store is having a sale
on recliners buy two and get a discount of $125
Sanjay purchases two recliners and the total cost
(before taxes) is $400 What is the price of a single
recliner not including any discounts
6 Choose a variable to represent what you want to
find Decide how the items of information in the
problem relate to the variable and to each other
Then write an equation tying this all together
Independent Practice
7 On one side of a line place three negative variable
tiles and seven +1-tiles and then on the other side
place 28 +1-tiles
8 Let d represent the number of days Val rented the
bicycle
Flat rental fee $5500
Cost for d days of rental $850 middot dTotal cost $123
$850 times number of days plus flat fee equals total cost
darr darr darr darr darr darr darr $850 bull d + $55 = $123
Equation 85d + 55 = 123
9 Let r represent the number of refills
Refill mug cost $675
Cost for r refills $125 middot r Total cost $3175
$125 times number of refills plus refill mug cost equals total cost
darr darr darr darr darr darr darr $125 bull r + $675 = $3175
Equation 125r + 675 = 3175
10 Let n represent the number of weekday classes
The Saturday class lasts 60 minutes
The length of time for the weekday classes is 45 middot n
The total number of minutes for all classes in a week
is 28545 minutes times number of plus minutes for equals total minutes
weekday classes Saturday class
darr darr darr darr darr darr darr45 bull n + 60 = 285
Equation 45n + 60 = 285
11 Let n represent the number of African animals
Half the number of African animals is 1 __ 2 n
45 more than the number of African animals
means + 45
The total number of animals is 172
half times number of and 45 more than number equals total number
African animals of African animals of animals
darr darr darr darr darr darr
1 _ 2
bull n + 45 = 172
Equation 1 __ 2 n + 45 = 172
12 Let u represent the number of uniforms
Cost for basketball equipment $548
Cost for u uniforms $2950 middot uTotal cost $2023
$2950 times number of plus cost for basketball equals total cost
uniforms equipment
darr darr darr darr darr darr darr $2950 bull u + $548 = $2023
Equation 295u + 548 = 2023
13 Let x represent the number of weeks
Initial amount in account $500
$20 per week 20 middot xFinal amount in account $220
initial amount minus 20 times number of equals final amount
weeks
darr darr darr darr darr darr darr 500 - 20 bull x = 220
Equation 500 - 20x = 220
14 a The equation adds 25 but Deenarsquos scenario
involves subtracting 25
b Let x represent the number of shirts
Cost of shirts before discount 9 middot xDiscount means subtract
Amount of discount $25
Total bill $88
9 times number of minus discount equals total
shirts bill
darr darr darr darr darr darr darr 9 bull x - 25 = 88
Equation 9x - 25 = 88
c Sample answer I bought some shirts at the store
for $9 each and a pair of jeans for $25 making
my bill a total of $88 How many shirts did I buy
15 a Let c represent the number of children
Flat fee for Sandy $10
Cost per child for Sandy $5 middot cTotal charge for Sandy $10 + $5c
Total charge for Kimmi $25
To compare the two costs set these values equal
Equation 10 + 5c = 25
b Solve the equation to find c the number of
children a family must have for Sandy and Kimmi
to charge the same amount
10 + 5c = 25
10 - 10 + 5c = 25 - 10
5c = 15
5c ___ 5 = 15 ___
5
c = 3
3 children
c They should choose Kimmi because she charges
only $25 If they chose Sandy they would pay
10 + 5 ( 5 ) = $35
Copyright copy by Houghton Mifflin Harcourt 36 All rights reserved
Focus on Higher Order Thinking
16 To get Andresrsquo equation you can multiply every
number in Peterrsquos equation by 4 To get Peterrsquos
equation you can divide every number in Andrewrsquos
equation by 4 or multiply by 1 __ 4
17 Part of the equation is written in cents and part in
dollars All of the numbers in the equation should be
written either in cents or dollars
18 Sample answer Cici has a gift card with a balance
of 60 She buys several T-shirts for $8 each Her new
balance is $28 after the purchases Write an
equation to help find out how many T-shirts Cici
bought
LESSON 64
Your Turn
1 Model the equation
+ ++ +
+ ++ ++ +
+ ++ ++ +
++
Remove 5 +1-tiles from each side of the mat
+ ++ +
+ ++ ++ +
+ ++ ++ +
++
Divide each side into two equal groups
++
+ ++ +
++
The solution is x = 3
++ ++
2 Model the equation
+ + ++ + ++ +
+++
+++
__
Add 1 +1-tile to each side of the mat Note that
a negative-positive tile pair results in zero
+ + ++ + ++
++ +
+++
+++
__
Divide each side into two equal groups
+ + ++++ + +++
The solution is n = 3
+ + +++
3 Model the equation
++++
______
______
____
Add 3 +1-tiles to each side of the mat Note that
a negative-positive tile pair results in zero
++++
+
++
+
++
______
______
____
Divide each side into two equal groups
++++
____
The solution is a = -1
++ __
Copyright copy by Houghton Mifflin Harcourt 37 All rights reserved
4 Model the equation
____
________
++
Add 2 -1-tiles to each side of the mat Note that
a negative-positive tile pair results in zero
________
________
++
____
Divide each side into two equal groups
________
________
We get -y = -1
____
In order to change -y to y add a positive y-variable
tile to each side
++
__ ++ __
Add 1 +1-tile to each side of the mat
++++
__
The solution is y = 1
+++
6 3n + 10 = 37
Solve the equation for n
3n + 10 = 37
-10 ____
-10 ____
3n = 27
3n ___ 3 = 27 ___
3
n = 9
The triplets are 9 years old
7 n __ 4 - 5 = 15
Solve the equation for n
n __ 4 - 5 = 15
+5 ___
+5 ___
n __ 4 = 20
n __ 4 ( 4 ) = 20 ( 4 )
n = 80
The number is 80
8 -20 = 5 __ 9 ( x - 32 )
Solve the equation for x
-20 = 5 __ 9 ( x - 32 )
-20 = 5 __ 9 x - 160 ____
9
+ 160 ____ 9
______
+ 160 ____ 9
______
- 20 ___ 9 = 5 __
9 x
- 20 ___ 9 divide ( 5 __
9 ) = 5 __
9 x divide ( 5 __
9 )
4 20 times 9
1 _______
9 1 times 5
1 = x
- 4 __ 1 = x
-4 = x
The temperature in the freezer is -4degF
9 120 - 4x = 92
Solve the equation for x
120 - 4x = 92
-120 _____
-120 _____
- 4x = -28
-4x ____ -4
= -28 ____ -4
x = 7
She had 7 incorrect answers
Copyright copy by Houghton Mifflin Harcourt 38 All rights reserved
Guided Practice
1 To solve the equation with algebra tiles first remove
one +1-tile from both sides Then divide each side
into two equal groups
2 Remove 1 +1-tile from each side
++++
+ +++++++++
Divide each side into two equal groups
++++
++++++++
The solution is x = 4
++ + + + +
3 Let w = the width of the frame
2 times height plus 2 times width equals perimeter
darr darr darr darr darr darr darr darr darr2 bull 18 + 2 bull w = 58
Solve the equation
2 ( 18 ) + 2w = 58
36 + 2w = 58
36 - 36 + 2w = 58 - 36
2w = 22
2w ___ 2 = 22 ___
2
w = 11
The width is 11 inches
4 1200 minus 25x = 500
Solve the equation for x
1200 - 25x = 500
_ -1200 _ -1200
-25x = -700
-25x _____ -25
= -700 _____ -25
x = 28
The manager will reorder in 28 days
5 Use the inverse operations of the operations
indicated in the problem If the equation does
not involve parentheses use addition or subtraction
before multiplication or division to solve the
equation
Independent Practice
6 9s + 3 = 57
9s + 3 - 3 = 57 - 3
9s = 54
9s ___ 9 = 54 ___
9
s = 6
7 4d + 6 = 42
4d + 6 - 6 = 42 - 6
4d = 36
4d ___ 4 = 36 ___
4
d = 9
8 115 - 3y = -485
115 - 115 - 3y = -485 - 115
thinsp-3y = -60
-3y
____ -3
= -60 ____ -3
y = 20
9 k __ 2 + 9 = 30
k __ 2 + 9 - 9 = 30 - 9
k __ 2 = 21
2 sdot k __ 2 = 2 sdot 21
k = 42
10 g
__ 3 - 7 = 15
g
__ 3 - 7 + 7 = 15 + 7
g
__ 3 = 22
3 sdot g
__ 3 = 3 sdot 22
g = 66
11 z __ 5 + 3 = -35
z __ 5 + 3 - 3 = -35 - 3
z __ 5 = -38
5 sdot z __ 5 = 5 ( -38 )
z = -190
12 -9h - 15 = 93
-9h - 15 + 15 = 93 + 15
-9h = 108
-9h ____ -9 = 108 ____
-9
h = -12
13 - 1 __ 3 (n + 15) = -2
- 1 __ 3 n - 5 = -2
- 1 __ 3 n - 5 + 5 = -2 + 5
- 1 __ 3 n = 3
-3 sdot - 1 __ 3 n = -3 sdot 3
n = -9
14 -17 + b __ 8 = 13
-17 + 17 + b __ 8 = 13 + 17
b __ 8 = 30
8 sdot b __ 8 = 8 sdot 30
b = 240
Copyright copy by Houghton Mifflin Harcourt 39 All rights reserved
15 7 ( c - 12 ) = -21
7c - 84 = -21
_ +84 _ +84
7c = 63
7c ___ 7 = 63 ___
7
c = 9
16 -35 + p
__ 7 = -52
-35 + 35 + p
__ 7 = -52 + 35
p
__ 7 = -17
7 sdot p
__ 7 = -17 sdot 7
p = -119
17 46 = -6t - 8
46 + 8 = -6t - 8 + 8
54 = -6t
54 ___ -6
= -6t ____ -6
t = -9
18 Let a = the original amount in the account
Double the (original plus 26) equals new
sum of amount amount
darr darr darr darr darr darr
2 (a + $26) = $264
Solve the equation
2 ( a + 26 ) = 264
2 ( a + 26 )
_________ 2 = 264 ____
2
a + 26 = 132
a + 26 - 26 = 132 - 26
a = 106
Puja originally had $106 in the account
19 Let t = the temperature 6 hours ago
Twice temperature less 6 degrees equals current
6 hours ago temperature
darr darr darr darr darr darr 2middot t - 6 = 20
Solve the equation
2t - 6 = 20
2t - 6 + 6 = 20 + 6
2t = 26
2t __ 2 = 26 ___
2
t = 13
Six hours ago it was 13 degF in Smalltown
20 -35 = 5 __ 9 ( x - 32 )
-35 = 5 __ 9 x - 160 ____
9
+ 160 ____ 9
______
+ 160 ____ 9
- 155 ____ 9 = 5 __
9 x
thinsp- 155 ____ 9 divide ( 5 __
9 ) = 5 __
9 x divide ( 5 __
9 )
-thinsp 31
155 times 9
1
= x
9 1
times 5
1
- 31 ___ 1 = x
-31 = x
The temperature is -31degF
21 Let a = Artaudrsquos ageopposite of Artaudrsquos age add 40 equals 28
darr darr darr darr darr darr(-) a + 40 = 28
Solve the equation
-a + 40 = 28
-a + 40 - 40 = 28 - 40
-a = -12
-a ___ -1
= -12 ____ -1
a = 12
Artaud is 12 years old
22 Let c = number of customers when Sven startedtwice number of
customers when Sven started
plus 11 more equals present number of customers
darr darr darr darr darr2 middot c +11 = 73
Solve the equation
2c + 11 = 73
2c + 11 - 11 = 73 - 11
2c = 62
2c ___ 2 = 62 ___
2
c = 31
Sven had 31 customers when he started
23 Let p = original price of the jacket
half original less $6 equals amount
price paid
darr darr darr darr darr
1 __ 2
middot p -6 = 88
Solve the equation
1 __ 2 p - 6 = 88
1 __ 2 p - 6 + 6 = 88 + 6
1 __ 2 p = 94
2 sdot 1 __ 2 p = 2 sdot 94
p = 188
The original price was $188
Copyright copy by Houghton Mifflin Harcourt 40 All rights reserved
24 115 minus 8n = 19
Solve the equation for n
115 - 8n = 19
_ -115 _ -115
-8n = -96
-8n _____ -8
= -96 _____ -8
n = 12
They had 19 apples left after 12 days
25 -55x + 056 = -164
-55x + 056 - 056 = -164 - 056
-55x = -22
-55x ______ -22
= -22 _____ -22
x = 04
26 -42x + 315 = -651
-42x + 315 - 315 = -651 - 315
-42x = -966
-42x ______ -42
= -966 ______ -42
x = 23
27 k ___ 52
+ 819 = 472
k ___ 52
+ 819 - 819 = 472 - 819
k ___ 52
= -347
52 sdot k ___ 52
= 52 ( -347 )
k = -18044
28 Sample answer -3x - 5 = -26
29 Sample answer x __ 5 + 10 = 5
30 When dividing both sides by 3 the student forgot to
divide 2 by 3
3x + 2 = 15
3x ___ 3 + 2 __
3 = 15 ___
3
x + 2 __ 3 = 5
- 2 __ 3
___
- 2 __ 3
___
x = 5 - 2 __ 3
x = 5 times3
___ 1
times3 - 2 __
3
x = 15 ___ 3 - 2 __
3
x = 13 ___ 3 or 4 1 __
3
The solution should be x = 4 1 __ 3
31 a 2(x + 40) = 234
Solve the equation for x
2x + 80 = 234
2x + 80 - 80 = 234 - 80
2x = 154
2x ___ 2 = 154 ____
2
x = 77
Trey saved $77
b Sample answer In both solutions you would
divide $234 by 2 then subtract 40 234 divide 2 ndash 40
= 77 These are the same operations applied in
the same order as when solving the equation
Focus on Higher Order Thinking
32 F = 18c + 32
F - 32 = 18c + 32 - 32
F - 32 = 18c
F - 32 ______ 18
= 18c ____ 18
F - 32 ______ 18
= c
33 P = 2 ( ℓ + w ) P = 2ℓ + 2w
P - 2ℓ = 2ℓ - 2ℓ + 2w
P - 2ℓ = 2w
P - 2ℓ ______ 2 = 2w ___
2
P - 2ℓ ______ 2 = w
34 ax + b = c
ax + b - b = c - b
ax = c - b
ax ___ a = c - b ______ a
x = c - b ______ a
MODULE 6
Ready to Go On
1 Add the amounts for the cost of first day of the field
trip with the second day of the field trip where n is
the number of members in the club
15n + 60 + 12n + 95
Therefore the total cost of the two-day field trip can
be written as the expression 27n + 155
2 h + 97 = -97
_ -97 _ -97
h = -194
3 - 3 __ 4 + p = 1 __
2
+ 3 __ 4 + 3 __
4
p = 1 __ 2 + 3 __
4
p = 1 times2
___ 2
times2 + 3 __
4
p = 2 __ 4 + 3 __
4
p = 5 __ 4
4 -15 = -02k
-15 _____ -02
= -02k ______ -02
75 = k
Copyright copy by Houghton Mifflin Harcourt 41 All rights reserved
5 y ___
-3 = 1 __
6
y ___
-3 ( -3 ) = 1 __
6 ( -3 )
y = 1 __ 6 times -3 ___
1
y = -3 ___ 6
y = -1 ___ 2
6 - 2 __ 3
m = -12
- 2 __
3 m _____
- 2 __ 3 = -12 ____
- 2 __ 3
m = -12 divide - 2 __ 3
m = -12 ____ 1 divide - 2 __
3
m = -12 ____ 1 times - 3 __
2
m = -36 ____ -2
m = 18
7 24 = - t ___ 45
24 ( 45 ) = - t ___ 45
( 45 )
108 = -t
-108 = t
8 Let d represent the number of the day after the first
day for example d = 1 means the first day after the
day he started number of number number
2 times day after plus of sit-ups equals of sit-ups
first day first day today
darr darr darr darr darr darr darr
2 middot d + 15 = 33
Equation 2d + 15 = 33
9 5n + 8 = 43
5n + 8 - 8 = 43 - 8
5n = 35
5n ___ 5 = 35 ___
5
n = 7
10 y __
6 - 7 = 4
y __
6 - 7 + 7 = 4 + 7
y __
6 = 11
6 sdot y __
6 = 6 sdot 11
y = 66
11 8w - 15 = 57
8w - 15 + 15 = 57 + 15
8w = 72
8w ___ 8 = 72 ___
8
w = 9
12 g
__ 3 + 11 = 25
g
__ 3 + 11 - 11 = 25 - 11
g
__ 3 = 14
3 sdot g
__ 3 = 3 sdot 14
g = 42
13 f __ 5 - 22 = -25
f __ 5 - 22 + 22 = -25 + 22
f __ 5 = -03
5 sdot f __ 5 = 5 ( -03 )
f = -15
14 - 1 __ 4 (p + 16) = 2
- 1 __ 4 p - 4 = 2
- 1 __ 4 p - 4 + 4 = 2 + 4
- 1 __ 4 p = 6
-4 sdot - 1 __ 4 p = 6 sdot -4
p = -24
15 Sample answer Analyze the situation to determine
how to model it using a two-step equation Solve
the equation Interpret the solution in the given
situation
Copyright copy by Houghton Mifflin Harcourt 42 All rights reserved
MODULE 7 Inequalities
Are You Ready
1 9w = -54
9w ___ 9 = -54 ____
9
w = -6
2 b - 12 = 3
thinsp _ + 12 = _ + 12
b = 15
3 n __ 4
= -11
4 times n __ 4
= 4 ( -11 )
n = -44
4-7
ndash5ndash10 0 5 10
75 4 6
8 3 - (-5)
3 + 5
8
9 -4 - 5
-9
10 6 - 10
-4
11 -5 - (-3)
-5 + 3
-2
12 8 - (-8)
8 + 8
16
13 9 - 5
4
14 -3 - 9
-12
15 0 - (-6)
0 + 6
6
LESSON 71
Your Turn
4 y minus 5 ge minus7
_ +5 _ +5
y ge minus2
-4-5 -3 -2-1 0 1 2 3 4 5
Check Substitute 0 for y
minus1 ge -8
minus1(minus2) le -8(minus2)
2 le 16
5 21 gt 12 + x
_ -12 _ minus12
9 gt x
x lt 9
10 2 3 4 5 6 7 8 9 10
Check Substitute 8 for x
21 gt 12 + 8
21 gt 12 + 8
21 gt 20
6 -10y lt 60
-10y
_____ -10
lt 60 ____ -10
y gt -6
-10-9 -8 -7 -6 -5 -4 -3 -2-1 0 1
Check Substitute -5 for y
-10y lt 60
-10(-5) lt 60
50 lt 60
7 7 ge - t __ 6
7(-6) le - t __ 6 (-6)
-42 le t
t ge -42
-46 -45 -44 -43 -42 -41 -40-47
Check Substitute -36 for t
7 ge - t __ 6
7 ge - ( -36 ____
6 )
7 ge 6
8 Write and solve an inequality
Let m = the number of months
35m le 315
35m ____ 35
le 315 ____ 35
m le 9
Tony can pay for no more than 9 months of his gym
membership using this account
Guided Practice
1 -5 le -2
_ +7 _ +7
2 le 5
2 -6 lt -3
-6 ___ -3
gt -3 ___ -3
2 gt 1
3 7 gt -4
_ -7 _ -7
0 gtthinsp -11
Copyright copy by Houghton Mifflin Harcourt 43 All rights reserved
4 -1 ge -8
-1 ( -2 ) le -8 ( -2 )
2 le 16
5 n - 5 ge -2
_ +5 _ +5
n ge 3
-5 -4 -3 -2-1 0 3 4 51 2
Check Substitute 4 for n
n - 5 ge -2
4 - 5 ge -2
-1 ge -2
6 3 + x lt 7
_ -3 _ -3
x lt 4
-2-1 0 3 4 5 6 7 81 2
Check Substitute 3 for x
3 + x lt 7
3 + 3 lt 7
6 lt 7
7 -7y le 14
-7y
____ -7 ge 14 ___ -7
y ge -2
-5-6-7 -4 -3 -2-1 0 1 2 3
Check Substitute -1 for y
-7y le 14
-7 ( -1 ) le 14
7 le 14
8 b __ 5 gt -1
b __ 5 ( 5 ) gt -1 ( 5 )
b gt -5
-5-6-7-8 -4 -3 -2-1 0 1 2
Check Substitute 0 for b
b __ 5 gt -1
0 __ 5 gt
-1
0 gt -1
9 a -4t ge -80
b -4t ge -80
-4t ____ -4
le -80 ____ -4
t le 20
It will take the physicist 20 or fewer hours to change
the temperature of the metal
c The physicist would have to cool the metal for
more than 20 hours for the temperature of the
metal get cooler than -80deg C
10 You reverse the inequality symbol when you divide
or multiply both sides of an inequality by a negative
number
Independent Practice
11 x - 35 gt 15
_ + 35 _ +35
x gt 50
100 20 30 40 50 60 70 80 90100
Check Substitute 51 for x
x - 35 gt 15
51 minus 35 gt 15
16 gt 15
12 193 + y ge 201
_ -193 _ minus193
y ge 8
10 2 3 4 5 6 7 8 9 10
Check Substitute 9 for y
193 + y ge 201
193 + 9 ge 201
202 ge 201
13 - q
__ 7 ge -1
- q
__ 7 ( -7 ) le -1 ( -7 )
q le 7
8 9 105 6 70 1 2 3 4
Check Substitute ndash14 for q
- q
__ 7 ge -1
- -14 ____ 7 ge
-1
2 ge -1
14 -12x lt 60
-12x _____ -12
gt 60 ____ -12
x gt -5
0-10-9 -8 -7 -6 -5 -4 -3 -2-1
Check Substitute -4 for x
-12x lt 60
-12 ( -4 ) lt 60
48 lt 60
15 5 gt z -3
_ +3 _ +3
8 gt z
z lt 8
10 2 3 4 5 6 7 8 9 10
Check Substitute 7 for z
5 gt z - 3
5 gt 7 - 3
5 gt 4
Copyright copy by Houghton Mifflin Harcourt 44 All rights reserved
16 05 le y __
8
05 ( 8 ) le y __
8 ( 8 )
4 le y
y ge 4
8 9 105 6 70 1 2 3 4
Check Substitute 8 for y
05 le y __
8
05 le 8 __
8
05 le 1
17 Write and solve an inequality
Let x = the number of inches
12 + x le 28
_ -12 _ -12
x le 16
The puppy will grow at most 16 inches more
18 Write and solve an inequality
Let w = the total weight of the kittens
w __ 7 lt 35
w __ 7 ( 7 ) lt 35 ( 7 )
w lt 245
The possible combined weights of the kittens is any
weight less than 245 ounces but greater than 0
19 Write and solve an inequality
Let s = the number of sides
6s le 42
6s ___ 6 le 42 ___
6
s le 7
The length of a side is at most 7 inches
20 Write and solve an inequality
Let x = the amount Tom needs to spend
3025 + x ge 50
_ -3025 _ -3025
x ge 1975
Tom needs to spend at least $1975
21 Write and solve an inequality
Let w = the width of the region
155w ge 1705
155w ______ 155
ge 1705 _____ 155
w ge 11
The possible width of the region is at least 11 feet
22 Write and solve an inequality
Let t = the number of seconds
thinsp-12t lt -120
-12t _____ -12
gt -120 _____ -12
t gt 10
No let t be the number of seconds the descent
takes the inequality is ndash12t lt -120 so t gt 10 so
the submarinersquos descent takes 10 seconds or more
23 Write and solve an inequality
Let s = the amount of spinach
3s le 10
3s ___ 3 le 10 ___
3
s le 3 1 __ 3
The greatest amount of spinach she can buy is 3 1 __ 3
pounds
24 Write and solve an inequality
Let m = the amount of money Gary has
m ___ 05
le 55
m ___ 05
( 05 ) le 55 ( 05 )
m le 275
Gary has at most $275
25 Write and solve an inequality
Let x = the number of pounds of onions
125x le 3
125x _____ 125
le 3 ____ 125
x le 24
No 125x le 3 x le 24 so 24 pounds of onions is
the most Florence can buy 24 lt 25 so she cannot
buy 25 pounds
Focus on Higher Order Thinking
26 If you divide both sides of -7z ge 0 by -7 and do
not reverse the inequality symbol you get z ge 0
This is incorrect because if you choose a value from
the possible solutions such as z = 1 and substitute
it into the original equation you get -7 ge 0 which is
not true
27 x gt 9 for each inequality in each case the number
added to x is 9 less than the number on the right
side of each inequality so x gt 9 is the solution
28 Find the formula for the volume of a rectangular
prism
V = lwh
Write and solve an inequality
Let h = the height in inches
( 13 ) ( 1 __ 2 ) h lt 65
65h lt 65
65h ____ 65
lt 65 ___ 65
h lt 10
All heights greater than 0 in and less than 10 in
( 13 ) ( 1 __ 2 ) h lt 65 65h lt 65 h lt 10 A height cannot
be 0 or less than 0 so h gt 0 and h lt 10
Copyright copy by Houghton Mifflin Harcourt 45 All rights reserved
LESSON 72Your Turn
3 Let a represent the amount each member must
raise
Number of members 45
Starting amount $1240
Target amount $6000
starting number amount each is greater target
amount plus of members times member than or amount
must raise equal to
darr darr darr darr darr darr darr $1240 + 45 middot a ge $6000
Equation 1240 + 45a ge 6000
4 Let n represent the greatest number of rides Ella
can go on
Starting amount $40
Admission price $6
Cost for each ride $3
admission cost for number is less starting
price plus each ride times of rides than or amount
equal to
darr darr darr darr darr darr darr $6 + $3 middot n le $40
Equation 6 + 3n le 40
5 x is the solution of the problem the quantity you
are looking for
3x means that for a reason given in the problem
the quantity you are looking for is multiplied by 3
+ 10 means that for a reason given in the problem
10 is added to 3x
gt 30 means that after multiplying the solution x by
3 and adding 10 to it the result must be greater
than 30
Sample answer An exam consists of one essay
question worth 10 points and several multiple choice
questions worth 3 points each If Petra earns full
points on the essay question how many multiple
choice questions must she get right in order to get
a score greater than 30 points
6 x is the solution of the problem the quantity you are
looking for
5x means that for a reason given in the problem
the quantity you are looking for is multiplied by 5
-50 means that for a reason given in the problem
50 is subtracted from 5x
le 100 means that after multiplying the solution x by
5 and subtracting 50 from it the result must be less
than or equal to 100
Sample answer Miho has $100 to spend on her
garden She spends $50 on gardening supplies
Vegetable plants cost $5 each What is the greatest
number of plants she can buy
Guided Practice
1
- -- -
-
lt
++++++
+ + ++ + +
+
2
---
gt
+ + ++ + +
+ + ++ + +
+ + +
3 Let a represent the amount each member must
raise
Amount to be raised $7000
Amount already raised $1250
Number of members 92 amount number of amount each is greater target
already plus members times member than or amount
raised raises equal to
darr darr darr darr darr darr darr 1250 + 92 times a ge 7000
The inequality that represents this situation is
1250 + 92a ge 7000
4 x is the solution of the problem 7x is the solution
multiplied by 7 -18 means that 18 is subtracted
from 7x le 32 means that the result can be no
greater than 32
5 Sample answer Alexa has $32 to spend on T-shirts
for her friends She has a gift card worth $18 T-shirts
cost $7 each How many T-shirts can Alexa buy
6 Sample answer Choose a variable to represent
what you want to find Decide how the information in
the problem is related to the variable Then write an
inequality
Independent Practice
7 number possible amount is
of times amount each minus for more $200
friends friend earns supplies than
darr darr darr darr darr darr darr 3 middot a - $28 gt $200
3a + 28 gt 200
Let a = possible amount each friend earned
8 cost of number cost of less than amount
bagel times of bagels plus cream or equal Nick
cheese to has
darr darr darr darr darr darr darr $075 middot n + $129 le $700
075n + 129 le 700
Let n = the number of bagels Nick can buy
9 number max amount amount less than total amount
of shirts times each shirt minus of gift or equal Chet can
can cost certificate to spend
darr darr darr darr darr darr darr 4 sdot a - 25 le 75
4a - 25 le 75Let a = the maximum amount each shirt can cost
Copyright copy by Houghton Mifflin Harcourt 46 All rights reserved
10 number of number number of is less total
seats in plus of rows on times seats in than equal number
balcony ground floor one row equal to of people
darr darr darr darr darr darr darr 120 + 32 middot n le 720
120 + 32n le 720
Let n = the number of people in each row
11 amount commission amount greater than earning
earned per plus rate times of sales or equal to for this
month month
darr darr darr darr darr darr darr 2100 + 005 middot s ge 2400
2100 + 005s ge 2400
Let s = the amount of her sales
12 number number average greater
of cans plus of days times number of than goal
collected cans per day
darr darr darr darr darr darr darr 668 + 7 n gt 2000
668 + 7n gt 2000
Let n = the average number of cans collected each
day
13 cost per cost per number of less than total amount
month plus CD times CDs she or equal spent in
buys to a month
darr darr darr darr darr darr darr
$7 + $10 middot c le $100
7 + 10c le 100
Let c = the number of CDs Joanna buys
14 cost of cost for number of less than total amount
belt plus each times shirts he or equal of money
shirt can buy to Lionel has
darr darr darr darr darr darr darr
$22 + $17 middot n le $80
22 + 17n le 80
Let n = the number of shirts he can buy
15 Sample answer Mr Craig is buying pizzas for the
7th grade field day He can spend up to $130 and
needs 15 pizzas He has a $20 coupon How much
can he spend per pizza $10 or less per pizza
16 ldquoat leastrdquo in this case means m ge 25
17 ldquono greater thanrdquo in this case means k le 9
18 ldquoless thanrdquo in this case means p lt 48
19 ldquono more thanrdquo in this case means b le -5
20 ldquoat mostrdquo in this case means h le 56
21 ldquono less thanrdquo in this case means w ge 0
22 The average score of the three tests Marie has
already taken and the three she will still take
is given by
95 + 86 + 89 + 3s
________________ 6
where s is the average score on the three remaining
tests
This value needs to be greater than or equal to 90
so the inequality can be written as
95 + 86 + 89 + 3s
________________ 6 ge 90 or
95 + 86 + 89 + 3s ge 540 or
270 + 3s ge 540
Focus on Higher Order Thinking
23 5 + 10 lt 20 Sample answer If the combined length
of two sides of a triangle is less than the length of
the third side the two shorter sides will not be long
enough to form a triangle with the third side Here
the combined length of 5 ft and 10 ft is 15 ft not
enough to make a triangle
24 -m gt 0 Sample answer Since m is less than 0 it
must be a negative number -m represents the
opposite of m which must be a positive number
since the opposite of a negative number is positive
So -m gt 0
25 n gt 1 __ n if n gt 1
n lt 1 __ n if n lt 1
n = 1 __ n if n = 1
LESSON 73
Your Turn
1 Model the inequality
++
++++
+++
++++
++++
+++
gt
Add seven -1-tiles to both sides of the mat
++
++++
+++
++++
++++
+++
gt
- -- -- --
- -- -- --
Remove zero pairs from both sides of the mat
++
++++
gt
Divide each side into equal groups
++
++++
gt
Copyright copy by Houghton Mifflin Harcourt 47 All rights reserved
The solution is x gt 2
+ + +gt
2 Model the inequality
+++++
----
+++++
+ +++++
ge
Add four +1-tiles to both sides of the mat
+++++
----
+++++
+ ++
++++
+++
++++
ge
Remove zero pairs from the left side of the mat
+++++
+++++
+ +++++
++++
ge
Divide each side into equal groups
+++++
+++++
+ +++++
++++
ge
The solution is h ge 3
+ + + +ge
3 Use inverse operations to solve the inequality
5 - p
__ 6 le 4
5 - 5 - p
__ 6 le 4 - 5
thinsp- p
__ 6 le -1
thinsp-6 ( - p
__ 6 ) ge -6 ( -1 )
p ge 6
Graph the inequality and interpret the circle and
arrow
0 1 4 5 72 3 6 8 9 10
Joshua has to run at a steady pace of at least 6 mih
4 Substitute each value for v in the inequality
3v - 8 gt 22
v = 9 v = 10 v = 11
3 ( 9 ) - 8 gt 22 3 ( 10 ) - 8 gt 22 3 ( 11 ) - 8 gt 22
Evaluate each expression to see if a true inequality
results
3 ( 9 ) - 8 gt 22 3 ( 10 ) - 8 gt
22 3 ( 11 ) - 8 gt
22
27 - 8 gt 22 30 - 8 gt
22 33 - 8 gt
22
19 gt 22 22 gt
22 25 gt
22
not true not true true
v = 11
5 Substitute each value for h in the inequality
5h + 12 le -3
h = -3 h = -4 h = -5
5 ( -3 ) + 12 le -3 5 ( -4 ) + 12 le -3 5 ( -5 ) + 12 le -3
Evaluate each expression to see if a true inequality
results
5 ( -3 ) + 12 le -3 5 ( -4 ) + 12 le
-3 5 ( -5 ) + 12 le
-3
-15 + 12 le -3 -20 + 12 le
-3 -25 + 12 le
-3
-3 le -3 -8 le
-3 -13 le
-3
true true true
h = -3 h = -4 h = -5
Copyright copy by Houghton Mifflin Harcourt 48 All rights reserved
Guided Practice
1 Remove 4 +1-tiles from both sides then divide each
side into 3 equal groups the result is x lt 3
2 Use inverse operations to solve the inequality
5d - 13 lt 32
5d - 13 + 13 lt 32 + 13
5d lt 45
5d ___ 5 lt 45 ___
5
d lt 9
Graph the inequality
20 6 84 10 12 14 16 18 20
3 Use inverse operations to solve the inequality
-4b + 9 le -7
-4b + 9 - 9 le -7 - 9
-4b le -16
-4b ____ -4
ge -16 ____ -4
b ge 4
Graph the inequality
20 6 84 10 12 14 16 18 20
4 Substitute each value for m in the inequality
2m + 18 gt - 4
m = -12 m = -11 m = -10
2 ( -12 ) + 18 gt -4 2 ( -11 ) + 18 gt -4 2 ( -10 ) + 18 gt -4
Evaluate each expression to see if a true inequality
results
2 ( -12 ) + 18 gt -4 2 ( -11 ) + 18 gt
- 4 2 ( -10 ) + 18 gt
- 4
- 24 + 18 gt -4 - 22 + 18 gt
- 4 - 20 + 18 gt
- 4
- 6 gt - 4 - 4 gt
- 4 - 2 gt
- 4
not true not true true
m = -10
5 Substitute each value for y in the inequality
- 6y + 3 ge 0
y = 1 y = 1 __ 2 y = 0
-6 ( 1 ) + 3 ge 0 -6 ( 1 __ 2 ) + 3 ge 0 -6 ( 0 ) + 3 ge 0
Evaluate each expression to see if a true inequality
results
-6 ( 1 ) + 3 ge 0 - 6 ( 1 __
2 ) + 3 ge
0 - 6 ( 0 ) + 3 ge
0
-6 + 3 ge 0 -3 + 3 ge
0 0 + 3 ge
0
-3 ge 0 0 ge
0 3 ge
0
not true true true
y = 1 __ 2
y = 0
6 Solve the inequality
65 - 4t ge 15
65 - 65 - 4t ge 15 - 65
-4t ge -5
-4t ____ -4
le -5 ___ -4
t le 125
Graph the inequality
0 05 1 15 2 25
Lizzy can spend from 0 to 125 h with each student
No 15 h per student will exceed Lizzyrsquos available
time
7 Sample answer Apply inverse operations until you
have isolated the variable If you multiply or divide
both sides of the inequality by a negative number
reverse the direction of the inequality symbol
Independent Practice
8 2s + 5 ge 49
2s + 5 - 5 ge 49 - 5
2s ge 44
2s ___ 2 ge 44 ___
2
s ge 22
10 14 1612 18 20 22 24 26 28 30
9 -3t + 9 ge -21
-3t + 9 - 9 ge -21 -9
-3t ge -30
-3t ____ -3
le -30 ____ -3
t le 10
ndash2ndash4ndash6ndash8ndash10 0 2 4 6 8 10
10 55 gt -7v + 6
55 - 6 gt -7v + 6 - 6
49 gt - 7v
49 ___ -7 lt -7v ____ -7
v gt -7
-10-9 -8 -7 -6 -5 -4 -3 -2 -1 0
11 21 1 __ 3 gt 3m - 2 2 __
3
21 1 __ 3 + 2 2 __
3 gt 3m - 2 2 __
3 + 2 2 __
3
24 gt 3m
24 ___ 3 gt 3m ___
3
8 gt m or m lt 8
0 1 4 5 72 3 6 8 9 10
12 a ___ -8
+ 15 gt 23
a ___ -8
+ 15 - 15 gt 23 - 15
a ___ -8
gt 8
-8 ( a ___ -8
) lt -8 ( 8 )
a lt -64
-70 -68 -66 -64 -62 -60
Copyright copy by Houghton Mifflin Harcourt 49 All rights reserved
13 f __ 2 - 22 lt 48
f __ 2 - 22 + 22 lt 48 + 22
f __ 2 lt 70
2 ( f __ 2 ) lt 2 ( 70 )
f lt 140
100 110 120 130 140 150
14 -25 + t __ 2 ge 50
-25 + 25 + t __ 2 ge 50 + 25
t __ 2 ge 75
2 ( t __ 2 ) ge 2 ( 75 )
t ge 150
130 140 150 160 170 180
15 10 + g ___
-9 gt 12
10 - 10 + g ___
-9 gt 12 - 10
g ___
-9 gt 2
-9 ( g ___
-9 ) lt -9 ( 2 )
g lt -18
-20 -18 -14 -12 -10-16
16 252 le -15y + 12
252 - 12 le -15y + 12 - 12
24 le - 15y
24 ____ -15
ge -15y
_____ -15
y le -16
-20 -18 -14 -12 -10-16
17 -36 ge -03a + 12
-36 - 12 ge -03a + 12 - 12
-48 ge -03a
-48 _____ -03
le -03a ______ -03
a ge 16
10 11 12 13 14 16 17 18 19 2015
18 80 - 2w ge 50
80 - 80 - 2w ge 50 - 80
- 2w ge -30
-2w ____ -2
le -30 ____ -2
w le 15
The width is a positive number no greater than
15 inches the possible widths in inches will be 10
11 12 13 14 and 15
19 Inequality 7n - 25 ge 65
7n - 25 ge 65
7n - 25 + 25 ge 65 + 25
7n ge 90
7n ___ 7 ge 90 ___
7
n ge 12 6 __ 7
Grace must wash at least 13 cars because n must
be a whole number
Focus on Higher Order Thinking
20 No Sample answer If x lt x - 1 then subtracting
x from both sides of the inequality 0 lt -1 That is
untrue so no value of x can be less than x - 1
21 a
10 3 42 5 6 7 8 9 10
b
10 3 42 5 6 7 8 9 10
c A number cannot simultaneously be less than 2
and greater than 7 Therefore there is no number
that satisfies both inequalities
d Consider the graph of x gt 2 and x lt 7
The solution includes all the numbers on the
number line so the solution set is all numbers
22 Sample answer Joseph might have reasoned that n
was first multiplied by 2 then increased by 5 to give
a result less than 13 Working backward he would
have subtracted 5 from 13 ( to get 8 ) then divided by
2 ( to get 4 ) giving n lt 4 Shawnee would have
followed these same steps but would have used a
variable and invers operations
MODULE 7
Ready to Go On
1 n + 7 lt -3
thinsp _ -7
_ -7
n lt -10
2 5p ge -30
5p
___ 5 ge -30 ____
5
p ge -6
3 14 lt k + 11
_ -11 _ -11
3 lt k
4 d ___ -3
le minus6
( -3 ) ( d ) ge ( -3 ) ( -6 )
d ge 18
Copyright copy by Houghton Mifflin Harcourt 50 All rights reserved
5 c - 25 le 25
_ +25 _ +25
c le 5
6 12 ge -3b
12 ___ -3
le -3b _____ -3
-4 le b
7 Let n be the number of minimum points Jose must
score 562 + n ge 650
Solve the inequality
562 + n ge 650
_ -562 _ -562
n ge 88
8 Let t be the number of minutes Lainey can descend
-20 - 20t ge -100
9 2s + 3 gt 15
_ -3 _ -3
2s gt 12
2s ___ 2
gt 12 ___ 2
s gt 6
10 - d ___ 12
- 6 lt 1
_ +6 _ +6
- d ___ 12
lt 7
12 ( - d ___ 12
) lt 12 ( 7 )
-d lt 84
d gt -84
11 -6w - 18 ge 36
_ +18 _ +18
thinsp-6w ge 54
-6w _____ -6
le 54 ___ -6
w le -9
12 z __ 4 + 22 le 38
_ -22 _ -22
z __ 4 le 16
4 ( z __ 4 ) le 4 ( 16 )
z le 64
13 b __ 9 - 34 lt -36
_ +34 _ +34
b __ 9 lt -2
9 ( b __ 9 ) lt 9 ( -2 )
b lt -18
14 -2p + 12 gt 8
-12 ____
-12 ____
-2p gt -4
-2p
____ -2 lt -4 ___
-2
p lt 2
15 Sample answer Look for key words or phrases
that indicate inequality such as ldquogreater thanrdquo
ldquoless thanrdquo ldquoat mostrdquo or ldquoat leastrdquo
Copyright copy by Houghton Mifflin Harcourt 51 All rights reserved
MODULE 8 Modeling Geometric Figures
Are You Ready
1 3x + 4 = 10
3x + 4 - 4 =10 - 4
3x = 6
3x ___ 3 = 6 __
3
x = 2
2 5x - 11 = 34
5x - 11 + 11 = 34 + 11
5x = 45
5x ___ 5 = 45 ___
5
x = 9
3 -2x + 5 = -9
-2x + 5 - 5 = -9 - 5
-2x = -14
-2x ____ -2
= -14 ____ -2
x = 7
4 -11 = 8x + 13
-11 - 13 = 8x + 13 - 13
-24 = 8x
-24 ____ 8 = 8x ___
8
-3 = x
5 4x - 7 = -27
4x - 7 + 7 = -27 + 7
4x = -20
4x ___ 4 = -20 ____
4
x = -5
6 1 __ 2 x + 16 = 39
1 __ 2 x + 16 - 16 = 39 - 16
1 __ 2 x = 23
( 2 ) 1 __ 2 x = ( 2 ) 23
x = 46
7 12 = 2x - 16
12 + 16 = 2x - 16 + 16
28 = 2x
28 ___ 2 = 2x ___
2
14 = x
8 5x - 15 = -65
5x - 15 + 15 = -65 + 15
5x = -50
5x ___ 5 = -50 ____
5
x = -10
9 x __ 5 = 18 ___
30
x times 30 = 5 times 18
30x = 90
30x ____ 30
= 90 ___ 30
x = 3
10 x ___ 12
= 24 ___ 36
x times 36 = 12 times 24
36x = 288
36x ____ 36
= 288 ____ 36
x = 8
11 3 __ 9 = x __
3
3 times 3 = 9 times x
9 = 9x
9 __ 9 = 9x ___
9
1 = x
12 14 ___ 15
= x ___ 75
14 times 75 = 15 times x
1050 = 15x
1050 _____ 15
= 15x ____ 15
70 = x
13 8 __ x = 14 ___ 7
8 times 7 = x times 14
56 = 14x
56 ___ 14
= 14x ____ 14
4 = x
14 14 ___ x = 2 __ 5
14 times 5 = x times 2
70 = 2x
70 ___ 2 = 2x ___
2
35 = x
15 5 __ 6 = x ___
15
5 times 15 = 6 times x
75 = 6x
75 ___ 6 = 6x ___
6
125 = x
Solutions KeyGeometry
UNIT
4
Copyright copy by Houghton Mifflin Harcourt 52 All rights reserved
16 81 ___ 33
= x ____ 55
81 times 55 = 33 times x
4455 = 33x
4455 _____ 33
= 33x ____ 33
135 = x
LESSON 81
Your Turn
6 Length 132 in times 5 ft ____ 3 in
= 22 ft
Width 6 in times 5 ft ____ 3 in
= 10 ft
Area 10 ft ( 22 ft ) = 220 square feet
Guided Practice
1
Blueprint
length (in)3 6 9 12 15 18
Actual
length (ft)5 10 15 20 25 30
a The wall is 30 feet long
b 25 ft times 3 in ____ 5 ft
= 15 in
2 The width is 7 in times 4 ft ____ 2 in
= 14 ft and the length is
14 in times 4 ft ____ 2 in
= 28 ft and the area is
28 ft ( 14 ft ) = 392 square feet
3 Length 10 cm times 5 m _____ 2 cm
= 25 m
Width 6 cm times 5 m _____ 2 cm
= 15 m
Area 25 m ( 15 m ) = 375 square meters
4 a
b Length is 36 m and width is 24 m using both
scales
5 If the scale drawing is complete and accurate you
can use it to find any length or area of the object of
the drawing
Independent Practice
6 a 2 in times 40 cm ______ 1 in
= 80 cm
15 in times 40 cm ______ 1 in
= 60 cm
The dimensions of the painting are 80 cm by 60 cm
b 80 cm times 60 cm = 4800 c m 2
c 80 cm times 1 in _______ 254 cm
asymp 315 in
60 cm times 1 in _______ 254 cm
asymp 236 in
The dimensions of the painting are approximately
315 in by 236 in
d 315 in times 236 in asymp 743 i n 2
7 120 ft times 1 unit _____ 5 ft
= 24 units
75 ft times 1 unit _____ 5 ft
= 15 units
The dimensions of the drawing are 24 units by
15 units
8 Sample answer 2 in6 ft 1 in3 ft and 1 in1 yd
9 Because the scale is 10 cm1 mm and because
10 cm is longer than 1 mm the drawing will be
larger
10 a Let r represent the scale
54 ft times r = 810 m
r = 810 m ______ 54 ft
r = 150 m ______ 1 ft
The scale is 1 ft = 150 m
b 54 ft times 12 in _____ 1 ft
= 648 in
Let b represent the number of tiny bricks
b = 648 in times 1 brick ______ 04 in
b = 162 bricks
The model is 162 tiny bricks tall
11 a Let h represent the height of the model
h = 30 ft times 126 cm _______ 1 ft
h = 378 cm
Let n represent the number of toothpicks
n = 378 cm times 1 toothpick
_________ 63 cm
n = 6 toothpicks
The model will be 6 toothpicks tall
b 378 cm times 1 swab ______ 76 cm
asymp 5 swabs
The model will be about 5 cotton swabs tall
Focus on Higher Order Thinking
12 If the area of the scale drawing is 100 square cm
then one side is 10 cm Let s represent the side
length of the actual floor
s = 10 cm times 2 ft _____ 1 cm
s = 20 ft
So the area is 20 ft(20 ft) = 400 ft 2
The ratio of areas is 100 square cm 400 square feet
or 1 square cm 4 square feet
Copyright copy by Houghton Mifflin Harcourt 53 All rights reserved
13 Decide on the new scale yoursquod like to use Then find
the ratio between the old scale and the new scale
and redraw the scale drawing accordingly For
example the ratio could be 13 In that case you
would redraw the dimensions at three times the
original size
14 Sample answer 1 __ 4 in 8 ft 40 ft by 24 feet 960 f t
2
LESSON 82
Guided Practice
1 The two angles 45deg and a right angle or 90deg with
the included side 8 cm determine the point at which
the sides meet so a unique triangle is formed
2 The sum of the measures of the two short sides
4 + 3 = 7 The sum is less than the measure of the
long side 11 so no triangle is formed
3 The two angles 40deg and 30deg with the included side
7 cm determine the point at which the sides meet
so a unique triangle is formed
4 The sum of the measures of the two short sides
6 + 7 = 13 The sum is greater than the measure of
the long side 12 so a unique triangle is formed
5 Sample answer Segments with lengths of 5 in
5 in and 100 in could not be used to form a
triangle
Independent Practice
6 A figure with side lengths of 3 centimeters and 6
centimeters and an included angle of 120deg deter-
mine the length of the third side of a triangle and so
produce a unique triangle
6 cm
3 cm120˚
7 The side lengths proposed are 15 ft 21 ft and 37 ft
The sum of the measures of the two shorter sides
15 + 21 = 36 So the sum is less than the measure
of the long side 37 No such triangle can be created
8 The three angle measures can be used to form
more than one triangle The sign and the scale
drawing are two different-sized triangles with the
same angle measures
Focus on Higher Order Thinking
9 More than one triangle can be formed Two triangles
can be created by connecting the top of the 2-in
segment with the dashed line once in each spot
where the arc intersects the dashed line The
triangles are different but both have side lengths of
2 in and 1 1 __ 2 in and a 45deg angle not included
between them
10 The third side has a length of 15 in The third side
must be congruent to one of the other two sides
because the triangle is isosceles The third side
cannot measure 6 in because 6 + 6 is not greater
than 15 So the third side must measure 15 in
LESSON 83
Guided Practice
1 triangle or equilateral triangle
2 rectangle
3 triangle
4 rainbow-shaped curve
5 Sample answer Draw the figure and the plane
Independent Practice
6 Sample answer A horizontal plane results in cross
section that is a circle A plane slanted between
horizontal and vertical results in an oval cross
section A vertical plane through the cylinder results
in a rectangle A vertical plane along an edge of the
cylinder results in a line cross section
7 You would see circles or ovals with a cone but not
with a pyramid or prism
Focus on Higher Order Thinking
8 The plane would pass through the cube on a
diagonal from the top to the bottom of the cube
9 a It is a circle with a radius of 12 in
b The cross sections will still be circles but their
radii will decrease as the plane moves away from
the spherersquos center
10 The dimensions of two faces are 12 in by 8 in two
are 8 in by 5 in and two are 12 in by 5 in the
volume is 480 in 3
11 Sample answer If you think of a building shaped like
a rectangular prism you can think of horizontal
planes slicing the prism to form the different floors
Copyright copy by Houghton Mifflin Harcourt 54 All rights reserved
LESSON 84
Your Turn
5 Supplementary angles sum to 180deg Sample answer angFGA and angAGC
6 Vertical angles are opposite angles formed by two
intersecting lines
Sample answer angFGE and angBGC
7 Adjacent angles are angles that share a vertex and
one side but do not overlap Sample answer
mangFGD and mangDGC
8 Complementary angles are two angles whose
measures have a sum of 90deg Sample answer
mangBGC and mangCGD
9 Because mangFGE = 35deg and angFGE and angBGC are
vertical angles that means mangBGC = 35deg also
Because lines _
BE and _
AD intersect at right angles
mangBGD = 90deg so mangBGC + mangCGD = 90deg which means
mangBGC + mangCGD = 90deg 35deg + x = 90deg 35deg minus 35deg + x = 90deg minus 35deg x = 55deg
mangCGD = 55deg
10 angJML and angLMN are supplementary so their
measures sum to 180deg mangJML + mangLMN = 180deg 3x + 54deg = 180deg 3x + 54deg - 54deg = 180deg - 54deg 3x = 126deg
3x ___ 3 = 126deg ____
3
x = 42deg
mangJML = 3x = 3 ( 42deg ) = 126deg
11 Sample answer You can stop at the solution step
where you find the value of 3x because the measure
of angJML is equal to 3x
Guided Practice
1 angUWV and angUWZ are complementary angles
2 angUWV and angVWX are adjacent angles
3 angAGB and angDGE are vertical angles
so mangDGE = 30deg
4 mangCGD + mangDGE + mangEGF = 180deg 50deg + 30deg + 2x = 180deg 80deg + 2x = 180deg 2x = 100deg mangEFG = 2x = 100deg
5 mangMNQ + mangQNP = 90deg 3x - 13deg + 58deg = 90deg so 3x + 45deg = 90degThen 3x = 45deg and x = 15deg mangMNQ = 3x - 13deg = 3 ( 15deg ) - 13deg = 45deg - 13deg = 32deg
6 Sample answer Let mangS = x Write and solve an
equation ( x + 3x = 180deg ) to find x then multiply the
value by 3
Independent Practice
7 Sample answer angSUR and angQUR are adjacent
They share a vertex and a side
8 Sample answer angSUR and angQUP
9 Sample answer angTUS and angQUN
10 mangQUR = 139deg Sample answer angSUR and angSUP
are supplementary so mangSUP = 180deg - 41deg = 139deg angSUP and angQUR are vertical angles so they are
congruent and mangQUR = mangSUP = 139deg
11 mangRUQ is greater Sample answer angSUR and
angNUR are complementary so
mangNUR = 90deg - 41deg = 49deg mangTUR = 41deg + 90deg which is less than
mangRUQ = 49deg + 90deg
12 Because angKMI and angHMG are vertical angles their
measures are equal
mangKMI = mangHMG
84 = 4x
84 ___ 4 = 4x ___
4
x = 21deg
13 Because angKMH and angKMI are supplementary
angles the sum of their measures is 180deg mangKMH + mangKMI = 180deg x + 84 = 180
x + 84 - 84 = 180 - 84
x = 96
mangKMH = 96deg
14 Because angCBE and angEBF are supplementary
angles the sum of their measures is 180deg mangCBE + mangEBF = 180deg x + 62 = 180
x + 62 - 62 = 180 - 62
x = 118
mangCBE = 118deg
15 Because angABF and angFBE are complementary
angles the sum of their measures is 90deg mangABF + mangFBE = 90deg x + 62 = 90
x + 62 - 62 = 90 - 62
x = 28
mangABF = 28deg
16 Because angCBA and angABF are supplementary
angles the sum of their measures is 180deg mangABF = 28deg so
mangCBA + mangABF = 180deg x + 28 = 180 - 28
x + 28 - 28 = 152
mangCBA = 152deg
Copyright copy by Houghton Mifflin Harcourt 55 All rights reserved
17 If the two angles are complementary the sum of
their angles is 90degmangA + mangB = 90deg ( x + 4deg ) + x = 90deg 2x + 4deg = 90deg _ -4deg _ -4deg 2x = 86deg
2x ___ 2 = 86deg ___
2
x = 43degBecause x = mangB then mangB = 43deg and
mangA = 43deg + 4deg so mangA = 47deg
18 If the two angles are supplementary the sum of their
angles is 180degmangD + mangE = 180deg 5x + x = 180deg 6x = 180deg
6x ___ 6 = 180deg ____
6
x = 30degBecause x = mangE then mangE = 30deg and
mangD = 30deg x 5 so mangD = 150deg
19 If the two angles are complementary the sum of
their angles is 90deg When angles are divided into
minutes and seconds one apostrophe signifies a
minute and two apostrophes signifies a second
mangJ + mangK = 90deg0000
48deg268+ mangK = 90deg0000
_ -48deg268 _ -48deg268
mangK = 41deg3352
mangK = 41deg3352 or mangK = 41 degrees
33 minutes 52 seconds
Focus on Higher Order Thinking
20 Yes a parking lot can be built because the measure
of angle K is 180deg - ( 50deg + 90deg ) or 40deg which is
greater than 38deg
21 Disagree the sum of the measures of a pair of
complementary angles is 90deg So the measure of
each angle must be less than 90deg 119deg gt 90deg
22 a The sum of mangA and its complement will be 90deg Let x represent the complement
mangA + x = 90deg 77deg + x = 90deg _ -77deg = _ -77deg x = 13deg The complement of mangA has a measure of 13deg
and a complement of a complement of mangA
would have an angle equal to mangA or 77deg b A complement of a complement of an angle has
the same measure of the angle itself Let xdeg be
the measure of an angle The measure of a
complement of the angle is ( 90 - xdeg ) A complement of that angle has a measure of
( 90 - ( 90 - xdeg ) ) = ( 90 - 90 + xdeg ) = xdeg
MODULE 8
Ready to Go On
1
Living
roomKitchen Office Bedroom Bedroom Bathroom
Actual
ℓ times w ( ft ) 16 times 20 12 times 12 8 times 12 20 times 12 12 times 12 6 times 8
Blueprint
ℓ times w ( in ) 4 times 5 3 times 3 2 times 3 5 times 3 3 times 3 15 times 2
2 No The side lengths proposed are 8 cm 4 cm and
12 cm The sum of the measures of the two shorter
sides 4 + 8 = 12 So no such triangle can be
created
3 The longest side could be 15 cm because 20 cm is
too long given the lengths of the other sides
4 A circle is a possible cross section of a sphere
A point is another
5 A circle rectangle oval and line are possible cross
sections of a cylinder
6 mangBGC and mangFGE are vertical angles so
mangFGE = 50deg
7 If the two angles are complementary the sum of
their angles is 90deg mangS + mangY = 90deg
( 2 ( mangY ) - 30deg ) + mangY = 90deg 3 ( mangY ) - 30deg = 90deg _ +30deg = _ +30deg 3 ( mangY ) = 120deg
3 ( mangY ) ________ 3 = 120deg ____
3
mangY = 40deg
mangY = 40deg
8 Sample answer You can use scale drawings to plan
rooms or gardens
Copyright copy by Houghton Mifflin Harcourt 56 All rights reserved
MODULE 9 Circumference Area and Volume
Are You Ready
1 416
_ times 13
1248
_ +thinsp4160
5408
5408
2 647
_ times thinsp04
2588
2588
3 705
_ times thinsp94
2820
_ +thinsp63450
66270
6627
4 256
_ timesthinsp049
2304
_ +thinsp10240
12544
12544
5 1 __ 2 ( 14 ) ( 10 )
7 ( 10 )
70 i n 2
6 ( 35 ) ( 35 )
1225 ft 2
7 ( 8 1 __ 2 ) ( 6 )
17 ___ 1 2 sdot 6 3 __
1
51 i n 2
8 1 __ 2 ( 125 ) ( 24 )
1 __ 2 ( 24 ) ( 125 )
( 12 ) ( 125 )
15 m 2
LESSON 91
Your Turn
3 d = 11 cm
C = πd
C asymp 314 ( 11 )
C asymp 3454
The circumference is about 3454 cm
6 C = πd
44 asymp 314d
44 ____ 314
asymp d
d asymp 1401 yards
Divide the diameter of the garden by the digging
rate
1401 divide 7 = 2001
It takes Lars about 2 hours to dig across the garden
Guided Practice
1 d = 9 in
C asymp 314 ( 9 )
C asymp 2826 in
2 r = 7 cm
C = 2πr
C asymp 2 ( 22 ___ 7 ) ( 7 )
C asymp 44 cm
3 d = 25 m
C = πd
C asymp 314 ( 25 )
C asymp 785 m
4 r = 48 yd
C = 2πr
C asymp 2 ( 314 ) ( 48 )
C asymp 3014 yd
5 r = 75 in
C = 2πr
C asymp 2 ( 314 ) ( 75 )
C asymp 471 in
6 Find the diameter
C = πd
66 asymp 314d
66 ____ 314
asymp 314d _____ 314
21 asymp d
Find the cost
Carlos needs 21 + 4 = 25 feet of rope
25 times $045 = $1125
Carlos will pay $1125 for the rope
7 Because C = π yd and C = πd d = 1 yd then
r = 05 yd
d = 1 yd
8 Because C = 788 ft and C = 2πr
2πr = 788
2πr ___ 2π
= 788 ____ 2π
r asymp 788 _______ 2 ( 314 )
r asymp 1255 ft
d = 2r asymp 2 ( 1255 ft )
d asymp 2510 ft
9 d = 2r so r = d __ 2 asymp 34 ___
2
r asymp 17 in
C = πd asymp 314 ( 34 )
C = 1068 in
Copyright copy by Houghton Mifflin Harcourt 57 All rights reserved
10 Use the formula C = πd and substitute
314 for π and 13 for the diameter
Independent Practice
11 d = 59 ft
C = πd
C asymp 314 ( 59 )
C asymp 1853 ft
12 r = 56 cm
C = 2πr
C asymp 2 ( 22 ___ 7 ) ( 56 )
C asymp 352 cm
13 d = 35 in
C = πd
C asymp ( 22 ___ 7 ) ( 35 )
C asymp 110 in
14 Sample answer In exercises 12 and 13 the radius
or diameter is a multiple of 7
15 r = 94 ft
d = 2r = 2 ( 94 )
d = 188 ft
C = πd
C asymp 314 ( 188 )
C asymp 590 ft
16 d = 475 in
r = d __ 2 = 475 ____
2
r = 2375 in
C = πd
C asymp 314 ( 475 )
C asymp 14915 in
17 d = 18 in
r = d __ 2 = 18 ___
2
r = 9 in
C = πd
C asymp 314 ( 18 )
C asymp 5652 in
18 r = 15 ft
C = 2πr
C asymp 2 ( 314 ) ( 15 ) = 942 ft
The cost for edging is C times $075 per foot
so ( 942 ) ( 075 ) = 7065 or about $707
19 C = πd
C asymp ( 22 ___ 7 ) ( 63 )
C asymp 198 ft
The distance traveled is 12 times the
circumference of the Ferris wheel so
distance = 12 ( 198 ) or about 2376 ft
20 C = πd asymp 314 ( 2 )
C asymp 628 ft
Converting km to ft
2 km sdot ( 3280 ft _______
1 km ) = 6560 ft
6560 ft
_______ 628 ft
= 104459
The wheel makes about 1045 revolutions
21 The distance your friend walks is half the
circumference of the pond
1 __ 2 C = 1 __
2 πd asymp 1 __
2 sdot 314 ( 025 ) = 03925
Your friend walks approximately 03925 mi
The difference is 03925 - 025 = 01425
Your friend walks about 014 mi farther
22 Capitol Rotunda Dimensions
Height 180 ft
Circumference 3015 ft
Radius r = C ___ 2π asymp 3015
_______ 2 ( 314 )
asymp 48 ft
Diameter d = 2r = 2 ( 48 ) = 96 ft
Focus on Higher Order Thinking
23 The length of the fence is half the circumference
plus the diameter
1 __ 2 C = 1 __
2 πd asymp 1 __
2 sdot 314 ( 30 ) = 471
The total distance is 471 + 30 = 771 ft
The total cost is the length of fence times the cost
per linear foot
( 771 ft ) ( $925 _____
ft ) = $71318
It will cost about $71318
24 The circumference of the patio is
C = πd asymp 314 ( 18 ) = 5652 ft
Converting the length of one strand of lights from
inches to feet
( 54 in ) ( 1 ft _____ 12 in
) = 45 ft
To find the number of strands of lights divide the
circumference by the length of one strand
5652 ft _______ 45 ft
= 1256
Because Sam cannot buy a fraction of a strand he
must buy 13 strands
25 The distance is the difference in the circumferences
C inner
= πd asymp 314 ( 150 ) = 471 ft
The outer diameter is 150 ft + 2 ( 2 ft ) = 154 ft
C outer
= πd asymp 314 ( 154 ) = 48356 ft
The difference is 48356 - 471 = 1256 ft
It is about 1256 ft farther
26 No The circumference of the larger gear is about
πd asymp 314 ( 4 ) = 1256 inches The circumference of
the smaller gear is about πd asymp 314 ( 2 ) = 628
inches So the circumference of the larger gear is
628 inches more than the circumference of the
smaller gear
Copyright copy by Houghton Mifflin Harcourt 58 All rights reserved
27 Pool B about 057 m or 184 ft Sample answer
24 feet asymp 732 m so the diameter of Pool B is
greater and the circumference is greater
314 ( 75 ) - 314 ( 732 ) = 314 ( 018 ) asymp 057
057 m asymp 187 ft
LESSON 92
Your Turn
4 A = π r 2 A = π ( 10 ) 2
A asymp 314 ( 10 ) 2
A asymp 314 sdot 100
A asymp 314 f t 2
Guided Practice
1 r = d __ 2 = 14 ___
2 = 7 m
A = π r 2 A = π ( 7 ) 2
A asymp 314 ( 7 ) 2
A asymp 314 sdot 49
A asymp 1539 m 2
2 A = π r 2 A = π ( 12 ) 2
A asymp 314 ( 12 ) 2
A asymp 314 sdot 144
A asymp 4522 m m 2
3 r = d __ 2 = 20 ___
2 = 10 yd
A = π r 2 A = π ( 10 ) 2
A asymp 314 ( 10 ) 2
A asymp 314 sdot 100
A asymp 314 y d 2
4 A = π r 2 A = π ( 8 ) 2
A asymp 314 ( 8 ) 2
A asymp 314 sdot 64
A asymp 20096 i n 2
5 r = d __ 2 = 12 ___
2 = 6 cm
A = π r 2 A = π ( 6 ) 2
A asymp 314 ( 6 ) 2
A asymp 314 sdot 36
A asymp 11304 c m 2
6 r = d __ 2 = 13 ___
2 = 65 in
A = π r 2 A = π ( 65 ) 2
A asymp 314 ( 65 ) 2
A asymp 314 sdot 4225
A asymp 13267 i n 2
7 C = 4π = 2πr
4π ___ 2π
= 2πr ___ 2π
r = 2
A = π r 2 A = π ( 2 ) 2
A = 4π square units
8 C = 12π = 2πr
12π ____ 2π
= 2πr ___ 2π
r = 6
A = π r 2 A = π ( 6 ) 2
A = 36π square units
9 C = π __ 2 = 2πr
π __ 2 divide 2π = 2πr ___
2π
π __ 2 sdot 1 ___
2π = r
1 __ 4 = r
A = π r 2
A = π ( 1 __ 4 ) 2 = π ( 1 ___
16 )
A = π ___ 16
square units
10 A = π r 2 = 64π
π r 2 ___ π = 64π ____ π
r 2 = 64
r = 8
C = 2πr
= 2π ( 8 )
=16π yd
11 A = π r 2
Independent Practice
12 r = d __ 2 = 10 ___
2 = 5 in
A = π r 2 A = π ( 5 ) 2
A asymp 314 ( 5 ) 2
A asymp 314 sdot 25
A asymp 785 i n 2
13 A = π r 2 A = π ( 16 ) 2
A asymp 314 ( 16 ) 2
A asymp 314 sdot 256
A asymp 80384 c m 2
14 The area of the window is half the area of a circle of
diameter 36 in
r = d __ 2 = 36 ___
2 = 18 in
A semicircle
= 1 __ 2 π r 2
A semicircle
= 1 __ 2 π ( 18 ) 2
A semicircle
asymp 1 __ 2 ( 314 ) ( 18 ) 2
A semicircle
asymp 05 sdot 314 sdot 324
A asymp 50868 i n 2
Copyright copy by Houghton Mifflin Harcourt 59 All rights reserved
15 If the point ( 3 0 ) lies on the circle and the origin is
its center the radius of the circle is 3 units
A = π r 2 A = π ( 3 ) 2
A asymp 314 ( 3 ) 2
A asymp 314 sdot 9A asymp 2826 square units
16 The difference in areas is given by
A r = 75 mi
- A r = 50 mi
π ( 75 ) 2 - π ( 50 ) 2
= π ( 7 5 2 minus 5 0 2 ) = π ( 5625 minus 2500 ) = π ( 3125 ) asymp 98125
The area of the relayed signal is about 9813 mi 2
greater
17 The area of the field which is not reached by the
sprinkler is the area of the field minus the area
reached by the sprinkler or s 2 minus π r 2 where
s = 12 m and r is the radius of the circular area The
diameter of the circle is equal to a side of the field
12 m so the radius is 12 ___ 2 = 6 m So
s 2 minus π r 2 = 1 2 2 minus π ( 6 ) 2
= 144 minus π ( 36 )
asymp 144 minus 11304 = 3096
The area not reached by the sprinkler is
approximately 3096 m 2
18 No the area of the regular pancake is 4π in 2 and the
area of the silver dollar pancake is π in 2 so the area
of the regular pancake is 4 times the area of the
silver dollar pancake
19 No the top of the large cake has an area 9 times
that of the small cake The area of the top of the
large cake is 144π in 2 and that of the small cake is
16π in 2
20 Sample answer First find the radius of the circle by
using the formula C = 2πr Then substitute the
radius into the formula for the area of a circle
21 The 18-inch pizza is a better deal because it costs
about $20
_____ π ( 9 ) 2
asymp $008 or 8 cents per square inch
while the 12-inch pizza costs about $10
_____ π ( 6 ) 2
asymp $009
or 9 cents per square inch
22 a Because the bear can walk at a rate of 2 miles
per hour and was last seen 4 hours ago the
radius of the area where the bear could be found
is given by ( 2 miles per hour ) ( 4 hours ) = 8 miles
A = π r 2 = π ( 8 ) 2
= π ( 64 )
asymp 20096
The searchers must cover an area of about
201 mi 2
b The additional area is the difference in areas of
circles with radii ( 2 miles per hour ) ( 5 hours )
= 10 miles and the original 8 miles
A new
minus A old
= π ( 10 ) 2 - π ( 8 ) 2
= π ( 1 0 2 - 8 2 ) = π ( 100 - 64 )
= π ( 36 ) asymp 11304
The searchers would have to cover about 113 mi 2
more area
Focus on Higher Order Thinking
23 No the combined area is 2π r 2 while the area of a
circle with twice the radius is 4π r 2
24 The area is multiplied by a factor of n 2
25 To find the part that is the bullrsquos-eye take the ratio of
the area of the bullrsquos-eye to that of the whole target
The radius of the bullrsquos-eye is 3 __ 2 = 15 in and
the radius of the whole target is 15 ___ 2 = 75 in
A
bullrsquos-eye ________
A whole target
=
π ( 15 ) 2 ______
π ( 75 ) 2
= ( 15 ) 2
_____ ( 75 ) 2
= 225 _____ 5625
= 004
The bullrsquos-eye is 004 or 4 of the whole target
LESSON 93
Your Turn
2 The figure can be separated into a rectangle and
two right triangles
The dimensions of the large rectangle are
length = 8 + 3 = 11 ft width = 4 ft
The dimensions of the two small triangles are
base = 3 ft height = 2 ft ( upper triangle ) base = 3 ft height = 3 ft ( lower triangle ) The area of the rectangle is
A = ℓw = 11 sdot 4 = 44 f t 2
The area of the upper triangle is
A = 1 __ 2 bh = 1 __
2 sdot 3 sdot 2 = 3 f t 2
The area of the lower triangle is
A = 1 __ 2 bh = 1 __
2 sdot 3 sdot 3 = 45 f t 2
Therefore the total area of the figure is
44 + 3 + 45 = 515 f t 2
3 The figure can be separated into a square and a
semicircle
Each side of the square is equal to 10 m
The radius of the semicircle is half the diameter
or 10 ___ 2 = 5 m
The area of the square is
A = s 2 = 1 0 2 = 100 m 2
The area of the semicircle is
A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 5 ) 2
A asymp 1 __ 2 sdot 314 sdot 25
A asymp 3925 m 2
Therefore the approximate total area of the figure is
100 + 3925 = 13925 m 2
Copyright copy by Houghton Mifflin Harcourt 60 All rights reserved
4 The composite figure is made up of a rectangle and two
semicircles which can be combined to form one circle
The dimensions of the rectangle are
length = 5 ft width = 4 ft
The diameter of the circle is 4 ft so the radius is
4 __ 2 = 2 ft
The area of the rectangle is
A = ℓw = 5 sdot 4 = 20 f t 2
The area of the circle is
A = π r 2 A asymp 314 sdot ( 2 ) 2
A asymp 314 sdot 4A asymp 1256 f t 2
The approximate total area is the sum of these
two areas
20 + 1256 = 3256 f t 2
Because the glass costs $28 per square foot
multiply the total area by the cost per square foot
( 3256 f t 2 ) ( $28 ____
f t 2 ) = $91168
It will cost about $91168 to replace the glass
Guided Practice
1 Separate the figure into a triangle a rectangle and
a parallelogram
Find the area of each figure
For triangle A = 1 __ 2 bh = 1 __
2 ( 4 ) ( 2 ) = 4
For rectangle A = ℓw = ( 5 ) ( 3 ) = 15
For parallelogram A = bh = ( 5 ) ( 3 ) = 15
Triangle 4 cm 2 rectangle 15 cm
2 parallelogram
15 cm 2
Step 3 Find the area of the composite figure
4 + 15 + 15 = 34 cm 2
The area of the irregular shape is 34 cm 2
2 Method 1
A 1 = ℓw A
2 = ℓw
= 12 sdot 9 = 20 sdot 9 = 108 = 180
Total area = 288 c m 2
Method 2
A 1 = ℓw A
2 = ℓw
= 9 sdot 8 = 12 sdot 8 = 72 = 216
Total area = 288 c m 2
3 Separate the figure into a trapezoid with h = 5 ft
b 1 = 7 ft and b 2 = 4 ft and a parallelogram with
base = 4 ft and height = 4 ft
For trapezoid A = 1 __ 2 h ( b
1 + b
2 )
A = 1 __ 2 ( 5 ) ( 7 + 4 )
A = 1 __ 2 ( 5 ) ( 11 ) = 275 f t 2
For parallelogram A = bh = ( 4 ) ( 4 ) = 16 f t 2
Find the area of the composite figure
275 + 16 = 435 ft 2
Multiply the total area by the cost per square foot to
find the cost
( 435 f t 2 ) ( $225 _____
f t 2 ) = $9788
4 The first step is separating the composite figure into
simpler figures
Independent Practice
5 Area of square A = s 2 = 2 6 2 = 676 i n 2
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 13 ) 2
A asymp 1 __ 2 sdot 314 sdot 169
A asymp 26533 i n 2
The approximate total area is the sum
676 + 26533 = 94133 in 2
6 a The floor of the closet is a composite of a
rectangle with length = 10 ft and width = 4 ft and
a triangle with base = 6 ft and height = 3 + 4 = 7 ft
Area of rectangle A = ℓw = 10 sdot 4 = 40 f t 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 6 sdot 7
A = 1 __ 2 sdot 42
A = 21 f t 2
The total area is the sum
40 + 21 = 61 f t 2
b The cost is the area multiplied by the cost per
square foot
( 61 f t 2 ) ( $250 _____
f t 2 ) = $15250
7
O 42-2-4
2
-4
y
A (-2 4) B (0 4)
C (2 1)D (5 1)
E (5 -2)F (-2 -2)
The area can be thought of as a composite of a
trapezoid and a rectangle
For trapezoid Let b 1 of the trapezoid be the
segment from the point ( -2 1 ) point C with length
4 units b 2 be from point A to point B with length
2 units and height equal to 3 units
For rectangle The corners of the rectangle are
( -2 1 ) D E and F Let the length of the rectangle
be 7 units and the width be 3 units
Area of trapezoid
A = 1 __ 2 h ( b
1 + b
2 )
A = 1 __ 2 ( 3 ) ( 4 + 2 )
A = 1 __ 2 ( 3 ) ( 6 ) = 9 square units
Copyright copy by Houghton Mifflin Harcourt 61 All rights reserved
Area of rectangle A = ℓw
A = 7 sdot 3 A = 21 square units
The total area is the sum
9 + 21 = 30 square units
8 The field is a composite of a square with side = 8 m
a triangle with base = 8 m and height = 8 m and a
quarter of a circle with radius = 8 m
Area of square A = s 2 = 8 2 = 64 m 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 8 sdot 8
A = 1 __ 2 sdot 64
A = 32 m 2
Area of quarter circle A = 1 __ 4 π r 2
A asymp 1 __ 4 sdot 314 sdot ( 8 ) 2
A asymp 1 __ 4 sdot 314 sdot 64
A asymp 5024 f t 2
The approximate total area is the sum
64 + 32 + 5024 = 14624 m 2
9 The bookmark is a composite of a rectangle with
length = 12 cm and width = 4 cm and two
semicircles which combine to form a full circle with
diameter = 4 cm so radius = 4 __ 2 = 2 cm
Area of rectangle A = ℓw = 12 sdot 4 = 48 c m 2
Area of circle A = π r 2 A asymp 314 sdot ( 2 ) 2
A asymp 314 sdot 4 A asymp 1256 c m 2
The approximate total area is the sum
48 + 1256 = 6056 cm 2
10 The pennant is a composite of a rectangle with
length = 3 ft and width = 1 ft and a triangle with
base = 1 ft and height = 1 ft
Area of rectangle A = ℓw = 3 sdot 1 = 3 f t 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 1 sdot 1
A = 1 __ 2 sdot 1
A = 05 f t 2
The area of one pennant is the sum
3 + 05 = 35 ft 2
Alex is making 12 pennants so the total area of all
12 pennants is 12 sdot 35 = 42 ft 2
The cost for the pennants will be the total area times
the fabric cost per square foot
( 42 f t 2 ) ( $125 _____
f t 2 ) = $5250
11 The area of the square is the total area minus the
area of triangle
325 ft 2 - 75 ft 2 = 25 ft 2
The area of a square is A = s 2 so s 2 = 25 f t 2
Because 5 sdot 5 = 25 the length of each side of the
square is 5 ft
Focus on Higher Order Thinking
12 The area of the garden can be found from counting
squares there are 18 full squares and 4 half-squares
for a total of 20 square units Each square unit will
grow about 15 carrots So Christina will grow about
20 ( 15 ) or 300 carrots
13 To find the length of the three sides of the square
subtract the lengths of the two sides of the triangle
from the perimeter The total length of three sides of
the square is 56 - 20 = 36 in Divide by 3 to find
that the length of one side and the base of the
triangle is equal to 12 in The total area of the figure
is the area of the square plus the area of the
triangle
Area of square A = s 2 = 1 2 2 = 144 i n 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 12 sdot 8
A = 1 __ 2 sdot 96
A = 48 i n 2
The total area is the sum
144 + 48 = 192 in 2
14 Think of the scarf as a rectangle minus two
semicircles The rectangle has length = 28 in and
width = 15 in The circle has diameter = 15 in so
its radius is 15 ___ 2 = 75 in
Area of rectangle A = ℓw = 28 sdot 15 = 420 i n 2
Area of circle A = π r 2 A asymp 314 sdot ( 75 ) 2
A asymp 314 sdot 5625
A asymp 176625 i n 2
The total area is the difference
420 - 176625 = 243375 in 2 or 243 3 __
8 i n 2
15 a The window is a composite of a square and a
semicircle Because each square in the window
has an area of 100 in 2 the length of each side is
10 in So each side of the square portion of the
entire window has length 10 sdot 4 = 40 in The
diameter of the semicircle is also 40 in so
the radius is 40 ___ 2 = 20 in
Area of square A = s 2 = 4 0 2 = 1600 i n 2
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 20 ) 2
A asymp 1 __ 2 sdot 314 sdot 400
A asymp 628 i n 2
The approximate total area is the sum
1600 + 628 = 2228 in 2
Copyright copy by Houghton Mifflin Harcourt 62 All rights reserved
b The shade is a composite of a rectangle and
a semicircle The length of the rectangle is equal
to the length of one side of the square portion
of the window plus 2 sdot 4 inches for a total of
40 + 2 sdot 4 = 48 in
The height of the rectangular portion of the shade
is equal to 4 times the length of one side of the
square portion of the window plus 4 inches for a
total of 40 + 4 = 44 in
The diameter of the semicircle at the top is the
same as the length of the bottom of the shade
48 in so the radius = 48 ___ 2 = 24 in
Area of rectangle A = ℓw = 48 sdot 44 = 2112 i n 2
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 24 ) 2
A asymp 1 __ 2 sdot 314 sdot 576
A asymp 90432 i n 2
The approximate total area of the shade is
the sum
2112 + 90432 asymp 3016 in 2
LESSON 94
Your Turn
3 Find the area of a base
B = l times w
= 9 times 2
= 18 square inches
Find the perimeter of the base
P = 2 ( 9 ) + 2 ( 2 )
= 18 + 4 = 22 inches
Find the surface area
S = Ph + 2B
S = 22 ( 1 1 __ 2 ) + 2 ( 18 )
= 33 + 36
= 69
The surface area of the box is 69 square inches
4 Find the area of the base of the larger prism
B = times w
= 12 times 12
= 144 square inches
Find the perimeter of the base
P = 4 ( 12 )
= 48 inches
Find the surface area of the larger prism
S = Ph + 2B
S = 48 ( 12 ) + 2 ( 144 )
= 576 + 288
= 864 square inches
Find the area of the base of the smaller prism
B = l times w
= 8 times 8
= 64 square inches
Find the perimeter of the base
P = 4 ( 8 )
= 32 inches
Find the surface area of the smaller prism
S = Ph + 2B
S = 32 ( 8 ) + 2 ( 64 )
= 256 + 128
= 384 square inches
Add the surface areas of the two prisms and
subtract the areas not stained (the bottom of the
larger prism and the smaller prism and an equal
area of the top of the larger prism where the smaller
prism sits) Surface area = 864 + 384 - 144 - 64
- 64 = 976 The surface area of the part of the plant
stand that she will stain is 976 square inches
Guided Practice
1 Perimeter of base = 5 + 5 + 8 = 18
Perimeter of base = 18 ft
Height = 7 ft
Base area = 1 __ 2 ( 3 ) ( 8 ) = 12 ft 2
Surface area
S = ( 18 ft ) ( 7 ft ) + 2 ( 12 ft 2 ) = 150 ft 2
2 Find the area of a base of the cube
B = l times w
= 25 times 25
= 625 m 2
Find the perimeter of the base of the cube
P = 4 ( 25 )
= 10 m
Find the surface area of the cube
S = Ph + 2B
S = 10 ( 25 ) + 2 ( 625 )
= 25 + 125
= 375
Surface area of cube
S = 375 m 2
Find the area of a base of the rectangular prism
B = l times w
= 11 times 9
= 99 m 2
Find the perimeter of the base of the rectangular
prism
P = 2 ( 11 ) + 2 ( 9 )
= 22 + 18
= 40 m
Find the surface area of the rectangular prism
S = Ph + 2B
S = 40 ( 7 ) + 2 ( 99 )
= 280 + 198
= 478
Surface area of rectangular prism
S = 478 m 2
Find the overlapping area the bottom of the cube
A = ( 25 ) ( 25 ) = 625
Overlapping area A = 625 m 2
Surface area of composite figure
= 375 + 478 -2 ( 625 ) = 503 m 2
3 Find the surface area of each of the prisms that
make up the solid Add the surface areas and
subtract the areas of any parts that are not on the
surface
Copyright copy by Houghton Mifflin Harcourt 63 All rights reserved
Independent Practice
4 Find the area of a base
B = l times w
= 10 times 3
= 30 in 2
Find the perimeter of the base
P = 2 ( 10 ) + 2 ( 3 )
= 20 + 6
= 26 in
Find the surface area
S = Ph + 2B
S = 26 ( 4 ) + 2 ( 30 )
=104 + 60
= 164 in 2
She needs 164 in 2 of wrapping paper
5 Find the area of the base
B = l times w
= 20 times 15
= 300 cm 2
Find the perimeter of the base
P = 2 ( 20 ) + 2 ( 15 )
= 40 + 30
= 70 cm
Find the surface area of the box
S = Ph + 2B
S = 70 ( 9 ) + 2 ( 300 )
= 630 + 600
= 1230 cm 2
Find the surface area of the top and sides
1230 - 300 = 930 cm 2
Find the area of a glass tile
Area of tile = 5 times 5 = 25 mm 2
Convert cm 2 to mm
2
930 cm 2 times 100 mm
2 ________
1 cm 2 = 93000 mm
2
Find the number of tiles needed
93000 divide 25 = 3720
3720 tiles are needed
6 Find the area of the L-shaped base
Area of L-shape = 2 times 1 + 3 times 1
= 2 + 3 = 5 in 2
Find the perimeter of the L-shaped base
Perimeter = 3 + 3 + 1 + 2 + 2 + 1
= 12 in
Find the surface area
S = Ph + 2B
S = 12 ( 3 ) + 2 ( 5 )
= 36 + 10
= 46 in 2
The surface area of each brace is 46 in 2
7 Find the area of the triangular prism
Perimeter = 25 + 25 + 3 = 8 ft
Base area = 1 __ 2 ( 2 ) ( 3 ) = 3 ft 2
Surface area = Ph + 2B
= 8 ( 4 ) + 2 ( 3 )
= 32 + 6 = 38 ft 2
Find the area of the rectangular prism
Perimeter = 2 ( 3 ) + 2 ( 4 ) = 14 ft
Base area = 3 times 4 = 12 ft 2
Surface area = Ph + 2B
= 14 ( 2 ) + 2 ( 12 )
= 28 + 24 = 52 ft 2
Add the surface areas of the two prisms and
subtract the parts not on the surface
Surface area = 38 + 52 - 12 - 12 = 66 ft 2
The total surface area of the doghouse is 66 ft 2
8 Treat the figure as ( 1 ) a composite of two triangular
prisms and one rectangular prism or ( 2 ) a prism
with a base that is a trapezoid
9 Find the area of the trapezoid base
Area of trapezoid = 1 __ 2 ( b
1 + b
2 ) h
1 __ 2 ( 16 + 48 ) 12 = 384 in
2
Find the perimeter of the base
P = 48 + 20 + 16 + 20 = 104 in
Find the surface area
S = Ph + 2B
S = 104 ( 24 ) + 2 ( 384 )
= 2496 + 768
= 3264 in 2
The surface area of the ramp is 3264 in 2
10 Find the area of the base of the larger prism
B = l times w
= 7 times l
= 7 ft 2
Find the perimeter of the base
P = 2 ( 7 ) + 2 ( 1 )
= 14 + 2
= 16 ft
Find the surface area of the larger prism
S = Ph + 2B
S = 16 ( 2 ) + 2 ( 7 )
= 32 + 14
= 46 f t 2
Find the area of the base of the smaller prism
B = l times w
= 1 times 1
= 1 ft 2
Find the perimeter of the base
P = 2 ( 1 ) + 2 ( 1 )
= 2 + 2 = 4 ft
Find the surface area of the smaller prism
S = Ph + 2B
S = 4 ( 3 ) + 2 ( 1 )
= 12 + 2
= 14 ft 2
Add the surface areas of the two prisms and
subtract the parts not on the surface
Surface area = 46 + 14 - 1 - 1 = 58 ft 2
The surface area of the stand is 58 ft 2
11 Find the number of cans of paint needed
58 divide 25 = 232
It takes 2 full cans and 1 partial can so 3 cans are
needed
Find the cost of 3 cans of paint
3 times 679 = 2037
No they need 3 cans which will cost $2037
Copyright copy by Houghton Mifflin Harcourt 64 All rights reserved
12 Find the area of the base of the box
B = l times w
= 27 times 24
= 648 cm 2
Find the perimeter of the base
P = 2 ( 27 ) + 2 ( 24 )
= 54 + 48
= 102 cm
Find the surface area of the box
S = Ph + 2B
S = 102 ( 10 ) + 2 ( 648 )
= 1020 + 1296
= 2316 cm 2
2316 cm 2 will be covered with paper
13 Area of the original base B = l times w
Area of the new base = 2l times 2w = 4lw = 4B
Perimeter of the original = 2l + 2w
Perimeter of the new = 2 ( 2l ) + 2 ( 2w ) =
2 ( 2l + 2w ) = 2P
Original S = Ph + 2B
New S = 2Ph + 2 ( 4B )
No Ph doubles and 2B quadruples S more than
doubles
Focus on Higher Order Thinking
14 Find the area of the base of the prism
B = l times w
= 25 times 25
= 625 ft 2
Find the perimeter of the base
P = 4 ( 25 )
= 10 ft
Find the surface area of the prism
S = Ph + 2B
S = 10 ( 35 ) + 2 ( 625 )
= 35 + 135
= 485 ft 2
Find the surface area less the area of the bottom
surface of the prism
485 - 625 = 4225 ft 2
Find what percent of the surface area less the area
of the bottom is compare to the total surface area
4225 _____ 485
times 100 asymp 87
Sample answer She would be painting about 87
of the total surface area so she will use about 87
of the total amount of paint
15
Circumference ofcircle πd = πtimes4
r = 2 in
9 in
Find the area of the circle base
A = πr 2
asymp 31 4 ( 2 ) 2 = 1256 in 2
Find the circumference of the circle
C = πd
asymp 314 ( 4 ) = 1256 in 2
Find the area of the rectangle
Area asymp 9 times 1256 = 11304 in 2
Find the surface area of the cylinder
S = Ch + 2B
asymp 1256 ( 9 ) + 2 ( 1256 ) = 13816 in 2
Round to the nearest tenth 1382 in 2
The surface area of the oatmeal box is
approximately 1382 in 2
Find the amount of cardboard for 1500 boxes
1500 times 1382 = 207300 in 2
Convert square inches to square feet and round to
the nearest whole number
( 207300 in 2 ) 1 ft 2 _______
144 in 2 asymp 1440 ft 2
It would take about 1440 ft 2 of cardboard
16 Each face has 9 squares 1 cm by 1 cm so S =
54 cm 2 The surface area stays the same when one
or more corner cubes are removed ( Fig 2 3 ) because the number of faces showing is still the
same In Fig 4 S increases because 2 more faces
show
LESSON 95
Your Turn
2 Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 24 ) 7
= 84 m 2
Find the volume of the prism
V = Bh
= ( 84 ) ( 22 )
= 1848 m 3
The volume of the prism is 1848 m 3
5 Find the base area B of the trapezoidal prism
B = 1 __ 2 ( b 1 + b 2 ) h
= 1 __ 2 ( 8 + 12 ) 10
= 1 __ 2 ( 20 ) 10 = 100 cm
2
Find the volume of the prism
V = Bh
= ( 100 ) ( 22 )
= 2200 cm 3
The volume of the prism is 2200 cm 3
7 Find the volume of each prism
Find the base area B of the rectangular prism
B = bh
= ( 13 ) 13
= 169 in 2
Find the volume of the rectangular prism
V = Bh
= ( 169 ) ( 30 )
= 5070 in 3
Copyright copy by Houghton Mifflin Harcourt 65 All rights reserved
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 9 ) 13
= 585 in 2
Find the volume of the triangular prism
V = Bh
= ( 585 ) ( 30 )
= 1755 in 3
Find the sum of the volumes
5070 + 1755 = 6825 in 3
The volume of the composite figure is 6825 in 3
Guided Practice
1 B = 1 __ 2 bh = 1 __
2 ( 8 ) ( 3 ) = 12 ft 2
V = Bh = ( 12 times 7 ) ft 3 = 84 ft 3
2 B = 1 __ 2 ( b 1 + b 2 ) h = 1 __
2 ( 15 + 5 ) 3 = 30 m
2
V = Bh = ( 30 times 11 ) m 3 = 330 m 3
3 Find the base area B of the rectangular prism
B = bh
= ( 4 ) 6 = 24 ft 2
Find the volume of the rectangular prism
V = Bh
= ( 24 ) ( 12 ) = 288 ft 3
The volume of the rectangular prism = 288 ft 3
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 6 ) 4 = 12 ft 2
Find the volume of the triangular prism
V = Bh
= ( 12 ) ( 6 ) = 72 ft 3
The volume of the triangular prism = 72 ft 3
Find the sum of the volumes
288 + 72 = 360 ft 3
The volume of the composite figure = 360 ft 3
4 Find the base area B of the rectangular prism
B = bh
= ( 40 ) ( 50 ) = 2000 ft 2
Find the volume of the rectangular prism
V = Bh
= ( 2000 ) ( 15 ) = 30000 ft 3
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 40 ) ( 10 ) = 200 ft 2
Find the volume of the triangular prism
V = Bh
= ( 200 ) ( 50 ) = 10000 ft 3
Find the sum of the volumes
30000 + 10000 = 40000 ft 3
The volume of the barn is 40000 ft 3
5 Find the base area B of the trapezoidal prism
B = 1 __ 2 ( b 1 + b 2 ) h
= 1 __ 2 ( 10 + 12 ) 5
= 1 __ 2 ( 22 ) 5 = 55 cm
2
Find the volume of the trapezoidal prism
V = Bh
= ( 55 ) ( 7 ) = 385 cm 3
The volume of the container is 385 cm 3
6 Find the volume of each prism using the formula
V = Bh Then add the volumes of all the prisms
Independent Practice
7 The area of the base of the prism is given 35 in 2
Find the volume of the prism
V = Bh
= ( 35 ) ( 5 ) = 175 in 3
The volume of the trap is 175 in 3
8 The shape of the ramp is triangular prism
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 7 ) ( 6 ) = 21 in
2
Find the volume of the triangular prism
V = Bh
= ( 75 ) ( 7 ) = 525 in 3
The volume of the ramp is 525 in 3
9 Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 8 ) ( 4 ) = 16 ft 2
Find the volume of the triangular prism
V = Bh
= ( 16 ) ( 24 ) = 384 ft 3
The space contained within the goal is 384 ft 3
10 Find the base area B of the trapezoidal prism
B = 1 __ 2 ( b 1 + b 2 ) h
= 1 __ 2 ( 7 + 5 ) 4
= 1 __ 2 ( 12 ) 4 = 24 in
2
Find the volume of the trapezoidal prism
V = Bh
= ( 24 ) ( 8 ) = 192 in 3
The volume of the gift box is 192 in 3
11 Find the volume of the triangular prism
V = Bh
= ( 20 ) ( 15 ) = 300 in 3
The units for volume are incorrect the volume is
300 cubic inches
12 The area of the base of the hexagonal prism is
given B = 234 in 3
Find the volume of the hexagonal prism
V = Bh
= ( 234 ) ( 3 ) = 702 in 3
Copyright copy by Houghton Mifflin Harcourt 66 All rights reserved
Find the base area B of the rectangular prism
B = bh
= ( 3 ) ( 3 ) = 9 in 2
Find the volume of the rectangular prism
V = Bh
= ( 9 ) ( 3 ) = 27 in 3
Find the sum of the volumes
702 + 27 = 972 in 3
The volume of the figure is 972 in 3
13 Find the base area B of the larger rectangular prism
B = bh
= ( 75 ) 375 = 28125 m 2
Find the volume of the larger rectangular prism
V = Bh
= ( 28125 ) ( 75 ) asymp 21094 cm 3
Find the base area B of the smaller rectangular
prism
Find the measure of the base
15 - 75 = 75
Find the base area B of the larger rectangular prism
B = bh
= ( 75 ) 375 = 28125 m 2
Find the volume of the smaller rectangular prism
V = Bh
= ( 28125 ) ( 375 ) asymp 10547 cm 3
Find the sum of the volumes of the prisms
21094 + 10547 = 31641 m 3
The volume of the figure rounded to the nearest
hundredth is 31641 m 3
14 Find the volume of the hexagonal candle
V = Bh
= ( 21 ) ( 8 ) = 168 cm 3
Find the amount of wax Josie would have after
making the hexagonal candle
260 - 168 = 92 cm 3
Find the volume of the triangular candle
V = Bh
= ( 7 ) ( 14 ) = 98 cm 3
Find the amount of wax Josie would have after
making the hexagonal candle
260 - 168 = 92 cm 3
Find the area of the base of a triangular candle with
a height of 14 cm
V = Bh
92 = B ( 14 )
92 ___ 14
= B ( 14 ) _____ 14
6 8 ___ 14
= B asymp 657
No the area of the base of the triangular candle
must be less than or equal to about 657 cm 2
15 The base of trapezoidal prism is given 36 in 2 Find
the volume of the trapezoidal prism
V = Bh
= ( 36 ) ( 5 ) = 180 in 3
The base of triangular prism is given 32 in 2
Find the volume of the trapezoidal
prism V = Bh
= ( 32 ) ( 6 ) = 192 in 3
Triangular prism you get 192 in 3 for the same price
you would pay for 180 in 3 with the trapezoidal prism
Focus on Higher Order Thinking
16 Find the area of the base of the trapezoidal prism
V = Bh
286 = B ( 8 )
286 ____ 8 = B ( 8 )
3575 = B
Find the missing dimension of the base of the
trapezoidal prism
1 __ 2 ( 2 + b 2 ) 13 = 3575
1 __ 2 ( 2 + b 2 ) ( 13 ___
13 ) = 3575 _____
13
( 2 ) 1 __ 2 ( 2 + b 2 ) = ( 2 ) 275
2 + b 2 = 55
_ -2 _ -2
b 2 = 35 ft
The missing dimension is 35 ft
17 Find the area of the base of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 10 ) 6 = 30 cm
2
Find the volume of the triangular prism
V = Bh
= ( 30 ) ( 25 ) = 75 cm 3
Find the mass of the doorstop
mass asymp ( V in cm 3 ) ( 86 g
_____ cm
3 )
asymp ( 75 cm 3 ) ( 86 g
_____ cm
3 ) = 645 g
The volume of the doorstop is 75 cm 3 The mass is
about 645 g
18 If both the base and height of the triangular base are
tripled the area of the base is multiplied by 9
Tripling the height of the prism as well means the
volume of the prism is multiplied by 27
19 Use the formula for the volume of a trapezoidal
prism to find a set of dimensions that have a volume
of 120 cm 3
V = Bh
V = [ 1 __ 2 ( b 1 + b 2 ) h 1 ] h 2
120 ≟ [ 1 __ 2 ( 2 + 6 ) 4 ] 75
= [ 1 __ 2 ( 8 ) 4 ] 75
= [ 16 ] ( 75 ) = 120
Try another set of dimensions in the formula
V = Bh
V = [ 1 __ 2 ( b 1 + b 2 ) h 1 ] h 2
120 ≟ [ 1 __ 2 ( 1 + 7 ) 25 ] 12
= [ 1 __ 2 ( 8 ) 25 ] 12
= [ 10 ] 12 = 120
Copyright copy by Houghton Mifflin Harcourt 67 All rights reserved
Sample answers ( 1 ) height of trapezoid = 4 cm
base lengths = 2 cm and 6 cm height of prism
= 75 cm ( 2 ) height of trapezoid = 25 cm base
lengths = 1 cm and 7 cm height of prism = 12 cm
MODULE 9
Ready to Go On
1 r = 7 m A = π r 2 C = 2πr A asymp 314 sdot ( 7 ) 2
C asymp 2 sdot 314 sdot 7 A asymp 314 sdot 49
C asymp 4396 m A asymp 15386 m 2
2 d = 12 cm d = 6 cm so r = 12 ___ 2 = 6 ft
C = πd A = π r 2 C asymp 314 ( 12 ) A asymp 314 sdot ( 6 ) 2
C asymp 3768 cm A asymp 314 sdot 36
A asymp 11304 ft 2
3 The figure is a composite of a semicircle with
diameter = 16 m so radius is 16 ___ 2 = 8m and a
triangle with base = 16 m and height = 10 m
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 8 ) 2
A asymp 1 __ 2 sdot 314 sdot 64
A asymp 10048 m 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 16 sdot 10
A = 1 __ 2 sdot 160
A = 80 m 2
The total area is the sum
80 + 10048 = 18048 m 2
4 The figure is a composite of a parallelogram with
base = 20 cm and height = 45 cm and a rectangle
with length = 20 cm and height = 55 cm
Area of parallelogram A = bh
A = 20 sdot 45
A = 90 c m 2
Area of rectangle
A = ℓw = 20 sdot 55 = 110 c m 2
The total area is the sum
90 + 110 = 200 cm 2
5 Find the area of the triangular base
Area of triangle = 1 __ 2 bh
1 __ 2 ( 4 ) 3 = 6 cm 2
Find the perimeter of the base
P = 3 + 4 + 5 = 12 cm
Find the surface area
S = Ph + 2B
S = 12 ( 10 ) + 2 ( 6 )
thinsp=120 + 12
thinsp= 132 cm 2
Find the volume of the prism
V = Bh
= ( 6 ) 10
= 60 cm 3
6 Find the area of the composite base formed by a
rectangle and a triangle
Area of triangle = 1 __ 2 bh
1 __ 2 ( 4 ) 15 = 3 yd 2
Area of rectangle = bh
( 4 ) 2 = 8 yd 2
Area of the composite base 3 + 8 = 11 yd 2
Find the perimeter of the composite base
P = 4 + 2 + 25 + 25 + 2 = 13 yd
Find the surface area
S = Ph + 2B
S = 13 ( 25 ) + 2 ( 11 )
thinsp= 325 + 22
thinsp= 545 yd 2
The area of the base of the pentagonal prism
is given
B = 234 yd 3
Find the volume of the prism
V = Bh
= ( 11 ) 25
= 275 yd 3
7 Sample answer You can use a composite figure to
model a room then find surface area to decide how
much paint you need to paint the room
Copyright copy by Houghton Mifflin Harcourt 68 All rights reserved
Solutions KeyStatistics
unit
5MODULE 10 Random Samples and Populations
Are You Ready
1 x ___16
=45___40
40x=720
40x ____40
=720____40
x=18
2 x __5=1__
4
4x=5
4x ___4
=5__4
x=5__4=125
3 25___10
=x ___10
125=10x
125____10
=10x ____10
125=x
4 x __6
=2__9
9x= 12
9x ___9
=12___9
x=12___9=4__
3
5 4748495152575960range=60-47=13
6 4566689121213range=13-4=9
7 95979799100106108115range=115-95=20
8 121319273539476671range=71-12=59
9 mean=3+5+7+3+6+4+8+6+9+5_________________________________10
=56
10 mean=81+94+113+67+62+75____________________________6
=82
LESSON 101
Your Turn
4 Yeseveryemployeehadanequalchanceofbeingselected
5 Thequestionisbiasedsincecatsaresuggested
6 ThequestionisnotbiasedItdoesnotleadpeopletopickaparticularseason
Guided Practice
1 Method1ASampleanswer
Random Sample of Seventh Grade Male Students
Student Shoe SizeArturo 75
Jimmy 80
Darnell 90
Ping 75
Zach 85
Jamar 80
BSampleanswer
75+80+90+75+85+80___________________________6
=485____6
asymp81
Meanasymp81
Method2ASampleanswer
Student Shoe Size Student Shoe SizeReggie 85 Ling 85
Stan 80 Marcus 90
Alejandro 90 Tio 85
BSampleanswer
85+80+90+85+90+85____________________________6
=515____6 =86
Mean=size86
2Method1producesresultsthataremorerepresentativeoftheentirestudentpopulationbecauseitisarandomsample
3 Method2producesresultsthatarelessrepresentativeoftheentirestudentpopulationbecauseitisabiasedsample
4 YesSampleanswerWhatisyourfavoritecolor
5 Selectarandomsampleofsufficientsizethatrepresentsthepopulationandaskeachparticipantunbiasedquestions
Independent Practice
6 SampleanswerPaulrsquossamplewasbiasedMaybehisfriendsstudiedmorethanothers
7 SampleanswerNancyrsquossampledidnotincludeasmanystationsThereportcouldincludestationsnationwide
8 ItisabiasedsampleStudentswhoarenrsquotontheteamwonrsquotbeselected
CopyrightcopybyHoughtonMifflinHarcourt 69 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U5M10indd 69 103113 216 AM
9 Itisbiasedbecausestudentswhoarenrsquotinthatclasswonrsquotbeselected
10 Itisarandomsamplebecauseallseventhgradershaveanequalchanceofbeingselected
11 Itisarandomsamplebecausetheorganizationselectsnamesatrandomfromallregisteredvoters
12 Itisbiasedbecausebasketballismentioned
13 Jaersquosquestionisnotbiasedsinceitdoesnotsuggestatypeofarttostudents
Focus on Higher Order Thinking
14 CollinrsquosmethodbetterrepresentstheentirestudentpopulationbecauseheusedarandomsampleKarlrsquosmethodpickedpeoplethatcouldallbefriendsthatgotofootballgamestogetherThesamplemaynotbestrepresenttheentirestudentpopulation
15 a Every10thstudentoutof600meansthatBarbarasurveyed60studentsThiswasarandomsample
b 35___60
= x ____100
xasymp58
Thepercentis58____100
=58
ItappearsreasonablebecauseBarbarausedarandomsampleandsurveyedasignificantpercentofthestudents
16 CarloiscorrectTherearemanyvalidwaystoselectarepresentativesamplefromapopulation
LESSON 102
Your Turn
5 damagedMP3sinsample
______________________sizeofsample
=damagedMP3sinpopulation
________________________sizeofpopulation
6___50
= x_____3500
6sdot70______50sdot70
= x _____3500
420_____3500
= x_____3500
x=420420damagedMP3s
Guided Practice
1
6 7 8 9 10 11 12 13 14 1550 1 2 3 4
2 Orderthedatafindtheleastandgreatestvaluesthemedianandthelowerandupperquartiles
6 7 7 107 114 4 54
Leastvalue
4
Lower quartile
4
Median
65
Upper quartile
7
Greatestvalue11
Drawaboxplot
10 1550
3 Themostcommonagesofchildrenthatusethelibraryare4and7
4 Therangeofagesofchildrenthatusethelibraryisfrom4to11
5 Themedianageofchildrenthatusethelibraryis65
6 defectivephonesinsample
______________________sizeofsample
=defectivephonesinpopulation
_________________________sizeofpopulation
4___60
= x_____4200
4sdot70______60sdot70
= x_____4200
280_____4200
= x_____4200
x=280About280smartphonesintheorderarelikelytobedefective
7 infectedelkinsample
__________________sizeofsample
=infectedelkinpopulation
____________________sizeofpopulation
8___50
= x_____4500
8sdot90______50sdot90
= x_____4500
720_____4500
= x_____4500
x=720About720elkarelikelytobeinfected
8 YoucansetupproportionsusinginformationobtainedinarandomsampleofthepopulationForinstancethenumberofdefectivepartsinabatchcanbeusedtopredicthowmanypartswillbedefectiveinadifferent-sizebatch
divide060
divide060
CopyrightcopybyHoughtonMifflinHarcourt 70 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U5M10indd 70 103113 218 AM
Independent Practice
9 number of people with mispriced item in sample
_______________________________________ size of sample
=
number of people with mispriced item in one day
_______________________________________ size of population
4 ___ 50
= x ____ 600
4 sdot 12 ______ 50 sdot 12
= x ____ 600
48 ____ 600
= x ____ 600
x = 48
About 48 people are likely to have a mispriced item
10 number of boxes with at least one broken crayon in sample
_______________________________________________ size of sample
=
total number of boxes with at least one broken crayon
___________________________________________ size of population
2 ___ 20
= x ____ 130
2 sdot 65 _______ 20 sdot 65
= x ____ 130
13 ____ 130
= x ____ 130
x = 13
About 13 boxes will have at least one broken crayon
11 number of puppies
________________ size of sample
= total number of puppies
___________________ size of population
12 ___ 60
= x _____ 1200
12 sdot 20 ______ 60 sdot 20
= x _____ 1200
240 _____ 1200
= x _____ 1200
x = 240
About 240 puppies are in all of the cityrsquos animal
shelters
12 number of hawks building nests
__________________________ size of sample
= total number of hawks
__________________ size of population
12 ___ 72
= x ______ 10800
12 sdot 150 _______ 72 sdot 150
= x ______ 10800
1800
______ 10800
= x ______ 10800
x = 1800
About 1800 hawks are building nests
13 Yes this seems reasonable because 23 + 27
_______ 2 = 25
is the median of the data
14 Order the data
11 12 12 12 13 13 13 14 14 14 15 17 18 18
19 22
The total number of marathoners is 16 and of those
12 run 13 miles or more
12 ___ 16
= x ____ 100
12 sdot 625 ________ 16 sdot 625
= x ____ 100
75 ____ 100
= x ____ 100
x = 75
No The statement should say that 75 of female
marathoners run 13 or more miles a week
15
6 7 8 9 1050 1 2 3 4
Sample answer Most students at Garland have 2 or
fewer siblings
16 The box plot should show that at least 50 of the
ages are between 20 and 40 years of age
17 Kudrey needs to find the median and the lower and
upper quartiles and plot those points He assumed
all quartiles would be equally long when each
quartile represents an equal number of data values
Focus on Higher Order Thinking
18 Yes the least and greatest data values The median
and quartiles may or may not be actual data values
depending on how many values are in the data
19 A box plot Since every number is different a dot
plot would only have one dot over each value which
doesnrsquot give much information The box plot would
show the median the range and where data values
are concentrated if in fact they are
20 The typical salary at this company is $24000 the
median Yes it is misleading the average is thrown
off by the outlier value of $79000
Copyright copy by Houghton Mifflin Harcourt 71 All rights reserved
9 a 56 + 43 + 62 + 63 + 33 + 34 + 38 + 51 + 59 + 59
___________________________________________ 10
= 498
The average is 498 palms
b 498 sdot 64 = 31872
There are about 3187 palms on the entire farm
Focus on Higher Order Thinking
10 55 + 57 + 57 + 58 + 59 + 59 + 59 + 59 + 59 + 61 + 62 + 62 + 63 + 64 + 66
_________________________________________________________________ 15
= 60
The mean height is 60 inches Yes it is a good sample generated randomly and contains about 20 of the entire
population so it should provide a good estimate of the mean height of all competitors But taking more samples to
gauge the variability among the samples would make for a more valid estimate
11 Sample answer Answers will vary based on each studentrsquos results but should be about 13 or 14
12 Sample answer The larger the size of the random sample the more likely it is to represent the population
accurately
LESSON 103
Guided Practice
1 (1 600) 20
2 50 51 600
3 No In the sample 4 numbers (38 26 31 and 31)
represent defective batteries which is 20 of the
total In the shipment 50 out of 600 or about 8 of
the batteries are defective
4 Sample answer A too-small or non-random sample
is likely to pick unrepresentative data values
Independent Practice
5 Shop A 10 ___ 50
times 500 = 100
Shop B 23 ____ 100
times 500 = 115
Shop C 7 ___ 25
times 500 = 140
Shop A sells 100 whole-wheat bagels
Shop B sells 115 whole-wheat bagels
Shop C sells 140 whole-wheat bagels
6 From most to least likely B A C Shop Brsquos sample
would be the most representative because it
contained the most bagels Shop Crsquos sample would
be the least representative because it contained the
fewest bagels
7 She could use either the Shop A or Shop B sample
Both use a sufficient number of bagels to be
reasonably accurate The sample from Shop C uses
too few bagels to be accurate
8 2 of the 20 T-shirts in the sample are below quality
standards Because 2 ___ 20
times 1000 = 100 the predic-
tion would be that about 100 of the 1000 T-shirts are
below quality standards This is 1 1 __ 3 times the actual
count of 75
Copyright copy by Houghton Mifflin Harcourt 72 All rights reserved
MODULE 10
Ready to Go On
1 The population is the customers in the companyrsquos
computer database The sample is biased because
the customers surveyed are more likely to value their
service
2 number of students who speak 3 or more languages
__________________________________________ size of sample
= total number of students ____________________ size of population
18 ____ 270
= x ______ 30330
18 sdot 337 ____
3 ________
270 sdot 337 ____ 3
= x ______ 30330
2022
______ 30330
= x ______ 30330
x = 2022
About 2022 students speak three or more
languages
3 Two of the random numbers 13 and 167 represent
defective MP3 players
simulated defective players
______________________ size of simulation
= defective players
______________ shipment
2 ___ 10
= x _____ 5000
2 middot 500 _______ 10 middot 500
= x _____ 5000
1000
_____ 5000
= x _____ 5000
x = 1000
Based on the sample about 1000 MP3 players are
defective
4 No the sample is too small compared to the size of
the shipment
5 Sample answer You can make predictions about
populations that are too large to survey
Copyright copy by Houghton Mifflin Harcourt 73 All rights reserved
MODULE 11 Analyzing and Comparing Data
Are You Ready
0875
1 8 ⟌ _
7000
_ -6 400
600
_ -560
40
_ -40
0
0875 875
08
2 5 ⟌ _
40
_ -4 0
0
08 80
025
3 4 ⟌ _
100
_ -80
20
_ -20
0
025 25
03
4 10 ⟌ _
30
_ -3 0
0
03 30
5 4 6 7 7 9 11 15 17
7 + 9
_____ 2 = 8
Median = 8
Mode = 7
6 36 37 40 43 44 49 50 51 56
Median = 44
Mode none
7 9 + 16 + 13 + 14 + 10 + 16 + 17 + 9
________________________________ 8
= 13
Mean = 13
8 108 + 95 + 104 + 96 + 97 + 106 + 94
________________________________ 7 = 100
Mean = 100
LESSON 111
Your Turn
2 Shape dot plots for field hockey players and
softball players have a similar spread
Center center of the field hockey dot plot is less
than the center for softball or basketball players
Spread dot plots for field hockey players and softball
players have a similar spread
3 The median is the middle value Listing the values
in order
1 4 4 4 5 5 5 6 6 6 6 7 7 8 11
In this case median 6 h
range 10 h
The median for internet usage is greater than the
median for exercise and the range is less than the
range for exercise
Guided Practice
1 Class A clustered around two areas
Class B clustered in the middle The dot plots
appear to have about half of the data clustered in
one area
2 Class A two peaks at 4 and 13 mi
Class B looks centered around 7 mi
3 Class A spread from 4 to 14 mi a wide gap with
no data
Class B spread from 3 to 9 mi
4 Class A
4 4 4 4 4 5 5 5 6 6 12 13 13 13 13 14 14
median 6
Class B
3 4 4 4 5 5 5 5 6 6 7 7 7 7 7 8 8 9
median 6
The median for both dot plots is 6 miles
5 Range for class A 14 - 4 = 10 mi
Range for class B 9 - 3 = 6 mi
6 The medians allow you to compare the centers
The ranges allow you to compare the spreads
Independent Practice
7 The dots have a relatively even spread with a peak
at 8 letters
8 The center of the graph is between 6 and 7 letters
9 The dots spread from 3 to 9 letters
10 The mean is the average
3 + 4 + 4 + 5 + 5 + 6 + 7 + 7 + 8 + 8 + 8 + 9
________________________________________ 12
74 ___ 12
asymp 617
Mean asymp 617
3 3 4 5 5 6 7 7 8 8 8 9
Because there are two middle values take their
average
6 + 7
_____ 2 = 13 ___
2 = 65
Median 65
Range 9 - 3 = 6
11 AL clustered in one small interval with an outlier to
the left
VA relatively uniform in height over the same
interval
Copyright copy by Houghton Mifflin Harcourt 74 All rights reserved
12 ALcenteredbetween8and9daysofrainVAcenteredaround10daysofrain
13 ALspreadsfrom1to12daysofrainanoutlierat1VAspreadsfrom8to12daysofrain
14 LynchburgVAhasmoreconsistentlevelsofrainandmorerainpermonthcomparedtoMontgomeryAL
15 GroupAclusteredtotheleftofsize9GroupBclusteredtotherightofsize9
16 OrderedvaluesforgroupA6577757575888888585913Thereare15itemsofdataSince15isoddthereisamiddlenumber8Sothereisnoneedtoaverageanyvalues
MedianforGroupAsize8OrderedvaluesforgroupB859999959595951010105105105115MedianforGroupBsize95
17 GroupArangewithoutlier=13-65=65withoutoutlier=9-65=25GroupBrange=115-85=3
18 SampleanswerGroupAcouldbechildrenandGroupBcouldbeadults
Focus on Higher Order Thinking
19 YesSampleansweronegroupoffivestudentscouldhavethefollowingnumberofpets12345Anothergroupoffivestudentscouldhavethefollowingnumberofpets13335Forbothgroupsofstudentsthemedianwouldbe3andtherangewouldbe4
20RangeanoutliergreatlyincreasestherangewhereasthemedianwillgenerallynotbegreatlyaffectedasitisinthemiddleofallthevaluesAdotplotwillshowboth
LESSON 112
Your Turn
3 SampleanswerTheboxeshavesimilarshapesalthoughGroupBhasashorterboxandshorterwhiskersGroupBrsquosmedianisgreaterthanGroupArsquosGroupBrsquosshorterboxmeansthemiddle50ofitsdataareclosertogetherthanthemiddle50ofGroupArsquos
4 SampleanswerTheshapeissimilartoStoreArsquosThemedianisgreaterthanStoreArsquosandlessthanStoreBrsquosTheinterquartilerangeisaboutthesameasStoreArsquosandlongerthanBrsquos
Guided Practice
1 Minimum72 Maximum88
2 Median79
3 Range88-72=16 IQR85-75=10
4 Themedianheightforhockeyplayersis70inthemedianheightforvolleyballplayersis74Thereforevolleyballplayershavethegreatermedianheight
5 Theminimumheightforhockeyplayersis64intheminimumheightforvolleyballplayersis67inSohockeyplayershavetheshortestplayer
6 IQRforhockeyplayers76-66=10IQRforvolleyballplayers78-68=10BothgroupshaveanIQRof10
7 SampleanswerMinimumandmaximumvaluesmedianrangeandIQRs
Independent Practice
8 CarAhasaminimumof165inandamaximumof210inCarBhasaminimumof160inandamaximumof205inCarAhasamedianof180inCarBhasamedianof185in
9 RangeofCarA210-165=45RangeofCarB205-160=45IQRofCarA195-170=25IQRofCarB200-175=25Bothcarshaverangesof45inandinterquartilerangesof25in
10 CarBhasagreatermediandistancethanCarATheinterquartilerangesarethesamesothemiddle50ofthejumpdistancesforthetwocarshavethesamevariability
11 CarAhaslessvariabilityinthelowestquarterofitsdataandgreatervariabilityinthehighestquarterofitsdataThevariabilityisreversedforCarB
12 CityBhasthelowestpriceof$400andalsohasthehighestpriceof$625
13 MedianforCityA$475MedianforCityB$450Difference475-450=$25CityAhasthehighermedianpriceanditis$25higher
14 SampleanswerCityBabout50ofcarsinCityBleaseforlessthan$450ascomparedtoonly25ofcarsinCityA
15 SampleanswerCityAhasagreatermediancarleasingcostthanCityBCityAhasagreaterIQRofcarleasingcoststhanCityBCityBhasamorepredictablecarleasingcostthanCityAforthemiddle50ofdatavalues
CopyrightcopybyHoughtonMifflinHarcourt 75 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U5M11indd 75 103113 221 AM
Focus on Higher Order Thinking
16 The box plot with the longer box has more variability
in the middle 50 of the values
17 You can identify the minimum and maximum values
and the range of the data You can identify the
quartiles including the lower and upper quartiles
and the median as well as the interquartile range
Together these values help you recognize the
center of the data both the median and the middle
50 It helps you to recognize how spread out the
data are overall and how spread out the middle
50 of the values are around the median A dot
plot contains all the data values which a box plot
does not
18 Sample answer The range tells you very little but
the interquartile range tells you how closely the
middle half of the data cluster around the median
LESSON 113
Your Turn
1 Team 1
Mean
44 + 47 + 67 + 89 + 55 + 76 +85 + 80 + 87 + 69 + 47 + 58 = 804
804 divide 12 = 67
Mean absolute deviation
ǀ 44 - 67 ǀ = 23 ǀ 47 - 67 ǀ = 20
ǀ 67 - 67 ǀ = 0 ǀ 89 - 67 ǀ = 22
ǀ 55 - 67 ǀ = 12 ǀ 76 - 67 ǀ = 9
ǀ 85 - 67 ǀ = 18 ǀ 80 - 67 ǀ = 13
ǀ 87 - 67 ǀ = 20 ǀ 69 - 67 ǀ = 2
ǀ 47 - 67 ǀ = 20 ǀ 58 - 67 ǀ = 11
Mean of absolute values
23 + 20 + 0 + 22 + 12 + 9 +18 + 13 + 20 + 2 + 20 + 11 = 170
170 divide 12 asymp 142
Team 2
Mean
40 + 32 + 52 + 75 + 65 + 70 +72 + 61 + 54 + 43 + 29 + 32 = 625
625 divide 12 asymp 521
Mean absolute deviation
ǀ 40 - 521 ǀ = 121 ǀ 32 - 521 ǀ = 201
ǀ 52 - 521 ǀ = 01 ǀ 75 - 521 ǀ = 229
ǀ 65 - 521 ǀ = 129 ǀ 70 - 521 ǀ = 179
ǀ 72 - 521 ǀ = 199 ǀ 61 - 521 ǀ = 89
ǀ 54 - 521 ǀ = 19 ǀ 43 - 521 ǀ = 91
ǀ 29 - 521 ǀ = 231 ǀ 32 - 521 ǀ = 201
Mean of absolute values
121 + 201 + 01 + 229 +129 + 179 + 199 + 89 +19 + 91 + 231 + 201 = 169
169 divide 12 asymp 141
Difference in means
67 - 521 = 149
149 divide 141 asymp 11
The difference of the means is about 11 times the
MAD
2 There is much more overlap between the two
distributions
Guided Practice
1 Class 1 mean
12 + 1 + 6 + 10 + 1 + 2 + 3 +10 + 3 + 8 + 3 + 9 + 8 + 6 + 8 = 90
90 divide 15 = 6
Class 2 mean
11 + 14 + 11 + 13 + 6 + 7 + 8 + 6 +8 + 13 + 8 + 15 + 13 + 17 + 15 = 165
165 divide 15 = 11
Class 1 mean absolute deviation
ǀ 12 - 6 ǀ = 6 ǀ 1 - 6 ǀ = 5 ǀ 6 - 6 ǀ = 0
ǀ 10 - 6 ǀ = 4 ǀ 1 - 6 ǀ = 5 ǀ 2 minus 6 ǀ = 4
ǀ 3 - 6 ǀ = 3 ǀ 10 - 6 ǀ = 4 ǀ 3 - 6 ǀ = 3
ǀ 8 - 6 ǀ = 2 ǀ 3 - 6 ǀ = 3 ǀ 9 - 6 ǀ = 3
ǀ 8 - 6 ǀ = 2 ǀ 6 - 6 ǀ = 0 ǀ 8 - 6 ǀ = 2
6 + 5 + 0 + 4 + 5 + 4 + 3 + 4 +3 + 2 + 3 + 3 + 2 + 0 + 2 = 46
46 divide 15 asymp 3
Class 2 mean absolute deviation
ǀ 11 - 11 ǀ = 0 ǀ 14 - 11 ǀ = 3 ǀ 11 - 11 ǀ = 0
ǀ 13 - 11 ǀ = 2 ǀ 6 - 11 ǀ = 5 ǀ 7 - 11 ǀ = 4
ǀ 8 - 11 ǀ = 3 ǀ 6 - 11 ǀ = 5 ǀ 8 - 11 ǀ = 3
ǀ 13 - 11 ǀ = 2 ǀ 8 - 11 ǀ = 3 ǀ 15 - 11 ǀ = 4
ǀ 13 - 11 ǀ = 2 ǀ 17 - 11 ǀ = 6 ǀ 15 - 11 ǀ = 2
0 + 3 + 0 + 2 + 5 + 4 + 3 + 5 +3 + 2 + 3 + 4 + 2 + 6 + 2 = 44
44 divide 15 asymp 3
2 Difference in means
11 minus 6 = 5
5 divide 3 asymp 167
3 Sample answer The variation and overlap in the
distributions make it hard to make any convincing
comparison
4 To see how statistical measures vary among the
different samples
Independent Practice
5 23 + 38 + 39 + 48 + 55 + 56 + 71 +86 + 57 + 53 + 43 + 31 = 600
600 divide 12 = 50
ǀ 23 - 50 ǀ = 27 ǀ 38 - 50 ǀ = 12
ǀ 39 - 50 ǀ = 11 ǀ 48 - 50 ǀ = 2
ǀ 55 - 50 ǀ = 5 ǀ 56 - 50 ǀ = 6
ǀ 71 - 50 ǀ = 21 ǀ 86 - 50 ǀ = 36
ǀ 57 - 50 ǀ = 7 ǀ 53 - 50 ǀ = 3
ǀ 43 - 50 ǀ = 7 ǀ 31 - 50 ǀ = 19
27 + 12 + 11 + 2 + 5 + 6 + 21 +36 + 7 + 3 + 7 + 19 = 156
156 divide 12 = 13
The mean is 50degF and the MAD is 13degF
Copyright copy by Houghton Mifflin Harcourt 76 All rights reserved
6 ǀ 23 - 8 ǀ = 15 ǀ 38 - 23 ǀ = 15
ǀ 39 - 24 ǀ = 15 ǀ 48 - 33 ǀ = 15
ǀ 55 - 40 ǀ = 15 ǀ 56 - 41 ǀ = 15
ǀ 71 - 56 ǀ = 15 ǀ 86 - 71 ǀ = 15
ǀ 57 - 42 ǀ = 15 ǀ 53 - 38 ǀ = 15
ǀ 43 - 28 ǀ = 15 ǀ 31 - 16 ǀ = 15
The difference between each average monthly
temperature for City 1 and the corresponding
temperature for City 2 is 15degF
7 50 - 15 = 35
The mean is 35degF and the MAD is 13degF The
mean for City 2 must be 15degF less than the mean
for City 1 and the MAD must be the same
8 50 - 35 = 15
15 divide 13 asymp 12
The difference in the means as a multiple of the
mean absolute deviations is about 12
9
0 4 8 12 16 20 24 28 32 36 40 44
Medians
School B
School A
0 4 8 12 16 20 24 28 32 36 40 44
Means
School B
School A
Both distributions show longer travel times for school
A The distributions of the medians show less
overlap so it is more convincing
10 State A 48 - 38 = 10
10 divide 6 asymp 17
State B 50 - 42 = 8
8 divide 4 = 2
Sample answer The difference in ages is more
significant for State A if you look at the difference in
mean ages but the difference in mean ages is more
significant in State B if you consider variability as
well
11 Smiths Range 70 - 64 = 6
Median 665
Thompsons Range 80 - 74 = 6
Median 77
77 - 665 = 105
105 divide 6 = 175
The difference in the medians is 175 times the
ranges
Focus on Higher Order Thinking
12 Sample answer Jill can reasonably expect the
median of the medians of the samples to be 35
The median of the medians should be close to the
median of the population which should be 35
The outcomes are equally likely
13 Sample answer Ramonrsquos results should produce
more reliable inferences The larger the sample
size the less variability there should be in the
distributions of the medians and means
14 Sample answer Sethrsquos statement is incorrect for any
situation in which the MADs of the population are
not very similar
MODULE 11
Ready to Go On
1 The mean for the start of the school year is given by
5 + 6 + 6 + 7 + 7 + 7 + 7 + 8 + 8 + 8 + 8 + 9 + 9 + 10
________________________________________________ 14
= 105 ____ 14
= 75 mi
The mean for the end of the school year is given by
6 + 6 + 7 + 7 + 8 + 8 + 8 + 8 + 9 + 9 + 9 + 10 + 10 + 10
__________________________________________________ 14
= 115 ___ 14
asymp 82 mi
In summary Start 75 mi End about 82 mi
2 The median is the middle value
List of ordered values for start of school year
5 6 6 7 7 7 7 8 8 8 8 9 9 10
Because there are two middle values take their
average
7 + 8
_____ 2 = 15 ___
2 = 75
Median 75
List of ordered values for end of school year
6 6 7 7 8 8 8 8 9 9 9 10 10 10
Because there are two middle values we would
generally take their average but since they are both
the same and equal to 8
Median 8
Therefore Start 75 mi End 8 mi
3 Range for start of school year 10 - 5 = 5 mi
Range for end of school year 10 - 6 = 4 mi
Therefore Start 5 mi End 4 mi
4 Median for Airplane A 210 in
Median for Airplane B 204 in
Airplane A has a greater median flight length
5 IQR for Airplane A 225 - 208 = 17 in
IQR for Airplane B 230 - 195 = 35 in
Airplane B has a greater interquartile range
Copyright copy by Houghton Mifflin Harcourt 77 All rights reserved
6 The means for the shade plants
7 + 11 + 11 + 12 + 9 + 12 + 8 + 10
______________________________ 8
= 10
The means for the sun plants
21 + 24 + 19 + 19 + 22 + 23 + 24 + 24
__________________________________ 8 = 22
Range of the shade plants 12 - 7 = 5
Range of the sun plants 24 - 19 = 5
Difference in the means 22 - 10 = 12
12 ___ 5
= 24
The difference in the means is 24 times the ranges
7 Sample answer By graphing real-world data you
can identify similarities and differences in related
groups
Copyright copy by Houghton Mifflin Harcourt 78 All rights reserved
MODULE 12 Experimental Probability
Are You Ready
1 6 ___ 10
= 6 divide 2 ______ 10 divide 2
= 3 __ 5
2 9 ___ 15
= 9 divide 3 ______ 15 divide 3
= 3 __ 5
3 16 ___ 24
= 16 divide 8 ______ 24 divide 8
= 2 __ 3
4 9 ___ 36
= 9 divide 9 ______ 36 divide 9
= 1 __ 4
5 45 ___ 54
= 45 divide 9 ______ 54 divide 9
= 5 __ 6
6 30 ___ 42
= 30 divide 6 ______ 42 divide 6
= 5 __ 7
7 36 ___ 60
= 36 divide 12 _______ 60 divide 12
= 3 __ 5
8 14 ___ 42
= 14 divide 14 _______ 42 divide 14
= 1 __ 3
075
9 4 ⟌ _
300
_ -2 80
20
_ -20
0
075
0875
10 8 ⟌ _
7000
_ -6400
600
_ -560
40
_ -40
0
0875
015
11 20 ⟌ _
300
_ -2 00
100
_ -100
0
015
038
12 50 ⟌ _
1900
_ -15 00
4 00
_ -4 00
0
038
13 67 = 67 ____ 100
= 067
14 31 = 31 ____ 100
= 031
15 7 = 7 ____ 100
= 007
16 146 = 100 + 46
= 100 ____ 100
+ 46 ____ 100
= 1 + 046
= 146
17 013 = 13
18 055 = 55
19 008 = 8
20 116 = 116
LESSON 121
Your Turn
3 Because every other number from 1 through 16 is
even choosing an even number is as likely as not
and the probability is 1 __ 2
4 There are 20 possible outcomes when picking a
marble from the jar There are 10 purple marbles
Therefore the probability of picking a purple marble
is 10 ___ 20
or 1 __ 2
5 There are 6 possible outcomes when rolling a cube
There are 2 numbers greater than 4 that can be
rolled 5 and 6 Therefore the probability of rolling a
number greater than 4 is 2 __ 6 or 1 __
3
Solutions KeyProbability
UNIT
6
Copyright copy by Houghton Mifflin Harcourt 79 All rights reserved
7 P(event) + P(complement) = 1
P(5) + P(not 5) = 1
1 __ 8 + P(not 5) = 1
P(not 5) = 7 __ 8
The probability of picking a marble that is not 5 is 7 __ 8
8 P(event) + P(complement) = 1
P(even) + P(odd) = 1
1 __ 2 + P(odd) = 1
P(odd) = 1 __ 2
The probability of rolling an odd number is 1 __ 2
Guided Practice
1 The cards are numbered 1 2 3 4 5 6 7 8 9 10
You pick a number greater than 0 8
You pick an even number 5
You pick a number that is at least 2 7
You pick a number that is at most 0 1
You pick a number divisible by 3 3
You pick a number divisible by 5 2
You pick a prime number 4
You pick a number less than the
greatest prime number 6
2 There are no green playing cards in a standard
deck so randomly picking a green card is
impossible 0
3 There are as many red cards as black cards in a
standard deck so it is as likely as not 1 __ 2
4 All of the numbers are less than 12 so they are also
less than 15 The probability is certain 1
5 There are only two numbers between 1 and 12 that
are divisible by 5 5 and 10 Therefore the probability
is unlikely close to 0
6 There are 5 possible outcomes when spinning the
spinner There are two even numbers 2 and 4
Therefore the probability of the spinner landing on
an even number is 2 __ 5
7 There are 52 possible outcomes when picking a
card from a standard deck There are 13 cards with
diamonds Therefore the probability of picking a
card with a diamond is 13 ___ 52
= 1 __ 4
8 P(event) + P(complement) = 1
P(5) + P(not 5) = 1
1 __ 6 + P(not 5) = 1
P(not 5) = 5 __ 6
The probability of not rolling 5 is 5 __ 6
9 P(event) + P(complement) = 1
P(blue) + P(not blue) = 1
1 __ 3 + P(not blue) = 1
P(not blue) = 2 __ 3
The probability of not landing on blue is 2 __ 3
10 P(event) + P(complement) = 1
P(4) + P(not 4) = 1
1 __ 5 + P(not 4) = 1
P(not 4) = 4 __ 5
The probability of not landing on 4 is 4 __ 5
11 P(event) + P(complement) = 1
P(queen) + P(not queen) = 1
4 ___ 52
+ P(not queen) = 1
P(not blue) = 48 ___ 52
= 12 ___ 13
The probability of not picking a queen is 12 ___ 13
12 Sample answer pulling a red marble out of a bag
that contains only blue marbles pulling a white
marble out of a bag that contains only white marbles
Independent Practice
13 There are 52 possible outcomes when picking from
a standard deck of cards There are 8 cards that
have an ace or a king Therefore the probability of
selecting
an ace or a king is 8 ___ 52
or 2 ___ 13
14 P(event) + P(complement) = 1
P(apple or peach) + P(not apple or peach) = 1
9 ___ 12
+ P(not apple or peach) = 1
P(not apple or peach) = 3 ___ 12
or 1 __ 4
Therefore the probability of picking a piece of fruit
that is not an apple or a peach is 3 ___ 12
or 1 __ 4
15 No it is unlikely that she will have oatmeal for
breakfast Since there are 4 choices the probability
that she will choose oatmeal is 1 __ 4 or 25
16 Purple There are a lot more plants with purple
flowers than with white flowers The probability of
selecting a white-flowered plant is 2 __ 9 while the
probability of selecting a purple-flowered plant is 7 __ 9
17 Because she has more colored T-shirts than white
T-shirts it is likely that she will pick a colored T-shirt
She has 14 total T-shirts and 10 of the shirts are
colored Therefore the probability she will choose a
colored T-shirt is 10 ___ 14
or 5 __ 7
18 1 None of the students in the class have red hair so
it is certain that a randomly chosen student will not
have red hair
Copyright copy by Houghton Mifflin Harcourt 80 All rights reserved
19 a There are 14 total coins and 8 blue coins so the
probability that the coin is blue is 8 ___ 14
or 4 __ 7
b Removing 1 of the 8 blue coins leaves 7 blue
coins Adding 3 more to the 6 red coins makes
9 red coins The total of coins in the bag is now
16 Therefore the probability of choosing a red
coin is 9 ___ 16
c Removing 1 of the 6 red coins leaves 5 red coins
Adding 3 to the 8 blue coins makes 11 blue coins
The total of coins in the bag is now 16 Therefore
the probability of choosing a red coin is 5 ___ 16
Focus on Higher Order Thinking
20 Sample answer If some marbles in a jar are heavier
than others then the heavier marbles would sink
and be less likely to be selected
21 Yes Because there are only two colors selecting
not black is equal to selecting red So
P(not black) + P(black) =P(not black) + P(not red) = 1
22 2 is the number of ways the event can happen 7 is
the number of outcomes in the sample space
landing on blue
LESSON 122
Your Turn
7 The total number of spins is 6 + 14 + 10 = 30
Red 10 ___ 30
= 1 __ 3
Yellow 14 ___ 30
= 7 ___ 15
Blue 6 ___ 30
= 1 __ 5
8 Sample answer Let 1 and 2 represent blue 3 and 4
represent white and 5 and 6 represent blue Toss
the cube 50 times to determine the experimental
probability for each color Predict the next ball will be
the color with the greatest experimental probability
Guided Practice
1 The total number of spins is 14 + 7 + 11 + 8 = 40
A 14 ___ 40
= 7 ___ 20
= 035 = 35
B 7 ___ 40
= 0175 = 175
C 11 ___ 40
= 0275 = 275
D 8 ___ 40
= 1 __ 5 = 020 = 20
2 Sample answer Write ldquoyesrdquo on 6 cards and ldquonordquo on
4 cards Draw a card at random 50 times Use the
number of ldquoyesrdquo cards drawn as the prediction
3 Use an experiment to find the number of times the
event occurs for a certain number of trials
Independent Practice
4 6 ___ 10
or 3 __ 5 It is reasonable to assume that Dreersquos
past performance is an indicator of her future
performance There is no way to accurately
represent 3 __ 5 on a number cube with 6 faces
5 Sample answer Compare the number of wins to the
total number of trials
number of wins _________________ total number of trials
= 8 ___ 48
= 1 __ 6
6 There are 20 possible outcomes when picking a
name Ryan is 1 person Therefore the probability
he is chosen is 1 ___ 20
and the probability he is not
chosen is 19 ___ 20
P(Ryan) + P(not Ryan) = 1
1 ___ 20
+ P(not Ryan) = 1
P(not Ryan) = 19 ___ 20
7 Yes because it is based on actual data of weather
patterns
8 Joan Mica hit the ball 8 ___ 48
times or about 17 of her
times at bat Meanwhile Joan hit the ball 12 ___ 40
times
or 30 of her times at bat Therefore Joan has the
greater experimental probability and is more likely to
get a hit next time
9 Gabbyrsquos experimental probability of hitting an ace
is 4 ___ 10
or 2 __ 5 Gabby could serve 16 aces in her next
40 serves because 2 __ 5 of 40 is 16
10 The experimental probability her dog wonrsquot want to
go outside is 5 ___ 12
or about 417
P(outside) + P(not outside) = 1
7 ___ 12
+ P(not outside) = 1
P(not outside) = 5 ___ 12
or 417
Focus on Higher Order Thinking
11 She did not add 40 and 60 to find the total number
of trials P(heads) = 40 ____ 100
12 Sample answer coin toss Heads represents male
and tails represents female Toss the coin 50 times
and use the results to make a prediction
13 Sample answer Make an index card to represent
each coin then pick one card at random No since
the coins are different sizes they do not each have
the same probability of getting pulled out of my
Copyright copy by Houghton Mifflin Harcourt 81 All rights reserved
LESSON 123
Your Turn
1 P(coffee + small) = number of coffee + small
_____________________ total number of orders
= 60 ____ 400
= 3 ___ 20
= 15
3 P(goId + 20 in) = number of gold + 20 in
_________________________ total number of necklaces sold
= 12 ___ 75
or 4 ___ 25
Guided Practice
1 P(female + age 22ndash39)
= number of female + age 22ndash39
__________________________ total number of patients
= 50 ____ 400
or 1 __ 8
2 Sample answer There are six possible outcomes
standard with vacuum standard with no vacuum
deluxe with vacuum deluxe with no vacuum
superior with vacuum and superior with no vacuum
Students could write the outcomes on six index
cards and put them in a box Then they can draw a
card 50 times record the results and find the
experimental probability that a customer chooses a
deluxe wash with no vacuum by dividing the
frequency of this compound event by 50 the total
number of trials
3 Find the number of occurrences of the compound
event and divide it by the total number of trials
Independent Practice
4 Divide the number of 2 piece + salad orders 33 by
the total number of orders 330
P = number of 2 piece + salad
______________________ total number of orders
= 33 ____ 330
= 1 ___ 10
5 P = number of red notebooks + 150 pages
_______________________________ total number of notebooks sold
= 60 ____ 400
= 3 ___ 20
6 P(red notebook) = number of red notebooks _____________________ total number of notebooks
= 55 + 60 + 23
____________ 400
= 138 ____ 400
= 69 ____ 200
7 12 the total is the product of 3 page-count choices
and 4 color choices
8 She left out the 53 students that read 150 pages
P(7th grade + 100 pages) = 85 ____ 250
= 17 ___ 50
9 Sample answer 8th grade the results table
suggests 8th grade students are the least likely to
have read 150 pages compared to students in 6th or
7th grade
Focus on Higher Order Thinking
10 Greater heads occurs on about half the occasions
that you roll a 6 so the compound event is half as
likely
11 Sample answer For 2 outcomes he could use even
and odd numbers For 3 outcomes he could use
1 or 2 3 or 4 and 5 or 6 For 6 outcomes he could
use each number once
12 P(male + open toe) = 11 ____ 300
P(male has open toe) = 11 ____ 150
No the first scenario
includes females and the second does not
13 No because coins are fair and the probabilities do
not appear to be equally likely
14 Sample answer On a coin heads = male and
tails = female On a number cube (1 or 2) = 6th
grade (3 or 4) = 7th grade and (5 or 6) = 8th
grade Toss the coin and roll the number cube 50
times each Record the number of outcomes that are
heads and 3 or 4
LESSON 124
Your Turn
1 024 times 550 =132 customers
2 No About 371 of the emails out of 12372 will come
back undelivered because 003 times 12372 asymp 371 The
editorrsquos prediction is too high
3 024 times 350 = 84 customers Yes because 107
customers buying two or more pairs would be more
than only 84 customers
Guided Practice
1 030 times 50 = 15 times
2 015 times 365 asymp 55 days
3 No about 1009 of the candles out of 16824 will be
returned because 006 times 16824 asymp 1009
A prediction of 812 is too low
4 No about 746 toys out of 24850 will be defective
because 003 times 24850 asymp 746 A prediction of 872 is
too high
5 98 ____ 100
= x ___ 40
= 39 ___ 40
or 39 times
No if she were late 6 out of 40 times the rate of
being on time would be only 85 in which case the
light-railrsquos claim of 98 is too high
6 18 ____ 100
= x _____ 5000
= 900 _____ 5000
or 900 students Yes the
collegersquos claim is close to the number actually
accepted
times04
times04
times50
times50
Copyright copy by Houghton Mifflin Harcourt 82 All rights reserved
7 Solve a proportion using the experimental probability
to find an expected number of events to happen
Make a prediction based on the expected number of
events
Independent Practice
8 4 ____ 100
= x ____ 200
= 8 ____ 200
or 8 students More students
moved than expected because 12 is more than 8
9 Yes 6th grade 2 ____ 100
= x ____ 250
= 5 ____ 250
or 5 students
7th grade 4 ____ 100
= x ____ 200
= 8 ____ 200
or 8 students
8th grade 8 ____ 100
= x ____ 150
= 12 ____ 150
or 12 students
Since 5 + 8 + 12 = 25 the values in the table
support his claim of 30 students
10 6 ____ 100
= x ____ 300
= 18 ____ 300
or 18 seats If an airplane is
overbooked with 310 passengers only 291 are
expected to show up since 310 times 94 asymp 291
11 006 times 600 = 36 clients If 40 clients did not pay it
would be slightly more than average
12 080 times 20 = 16 team members The coachrsquos claim is
not accurate because the average number of
students at practice is 144 ____ 8 = 8
13 He set up the fraction incorrectly it should be
1 ___ 30
= x ____ 180
Focus on Higher Order Thinking
14 1 __ 2 of 12 = 6 normal rejection rate
500 times 6 = 30 transactions rejected by a
normal gas pump
15 098 times 15000 = 14700 on-time flights Sample
answer No one week of data could be misleading
and not representative of the yearly on-time prob-
ability (because it ignores bad weather etc)
16 Sample answer No They could expect to get 96
responses with the old letter since
4 ____ 100
= x _____ 2400
= 96 _____ 2400
or 96 letters Therefore the
new letter received fewer responses
MODULE 12
Ready to Go On
1 H1 H2 T1 T2
2 6 ___ 10
= 3 __ 5
3 13 ___ 20
4 3 of the 7 total trials resulted in a sum more than 5
Therefore the experimental probability is 3 __ 7
5 I would predict he would reach first base 24 times
because 3 ___ 10
= x ___ 80
= 24 ___ 80
or 24 times
6 You can use the experimental probability based on
observation or simulation to set up a proportion and
use the proportion to predict a value
times15
times15
times24
times24
times2
times2
times3
times3
times2
times2
times25
times25
times8
times8
Copyright copy by Houghton Mifflin Harcourt 83 All rights reserved
MODULE 13 Theoretical Probability and
Simulations
Are You Ready
075
1 4 ⟌ _
300
_ -2 80
20
_ -20
0
075 = 75
04
2 5 ⟌ _
20
_ -2 0
0
04 = 40
09
3 10 ⟌ _
90
_ -9 0
0
09 = 90
035
4 20 ⟌ _
700
_ -6 00
1 00
_ -1 00
0
035 = 35
0875
5 8 ⟌ _
7000
_ thinsp-6 400
600
_ -560
40
_ -40
0
0875 = 875
005
6 20 ⟌ _
100
_ -1 00
0
005 = 5
076
7 25 ⟌ _
1900
_ -17 50
1 50
_ -1 50
0
076 = 76
046
8 50 ⟌ _
2300
_ -20 50
3 00
_ -3 00
0
046 = 46
9 1 - 1 __ 5 = 5 __
5 - 1 __
5
= 4 __ 5
10 1 - 2 __ 9 = 9 __
9 - 2 __
9
= 7 __ 9
11 1 - 8 ___ 13
= 13 ___ 13
- 8 ___ 13
= 5 ___ 13
12 1 - 3 ___ 20
= 20 ___ 20
- 3 ___ 20
= 17 ___ 20
13 8 ___ 15
times 5 __ 8 =
18 ___ 315
times 5 1 ___
8 1
= 1 __ 3
14 2 __ 9 times 3 __
4 =
12 __ 39
times 3 1 ___
4 2
= 1 __ 6
15 9 ___ 16
times 12 ___ 13
= 9 ___ 416
times 12 3 _____
13
= 27 ___ 52
16 7 ___ 10
times 5 ___ 28
= 17 ___
210 times 5
1 ____
28 4
= 1 __ 8
LESSON 131
Your Turn
2 The probability of an event is the ratio of the number
of ways the event can occur to the total number of
equally likely outcomes Therefore
P(rolling a 3 or 4) =
number of sides with 3 or 4 ________________________ total number of sides on cube
= 2 __ 6 = 1 __
3
3 The total number of outcomes in the sample space
is the denominator of the formula for theoretical
probability
Copyright copy by Houghton Mifflin Harcourt 84 All rights reserved
Guided Practice
1
Basket A Basket B
Total number of outcomes5 + 3 + 8
= 16
7 + 4 + 9
= 20
Number of red balls 3 4
P(win) =
Number of red balls
_____________________ Total number of outcomes
3 ___
16 4 ___
20 = 1 __
5
2 To compare the two probabilities of 1 __ 5 and 3 ___
16 use
the least common denominator of 80
1 __ 5 = 16 ___
80
3 ___ 16
= 15 ___ 80
Therefore 16 ___ 80
gt 15 ___ 80
so 1 __ 5 gt 3 ___
16
Choosing Basket B gives you a better chance of
winning
3 There are a total of 6 odd sections The total number
of sections (odd and even) is 11
P(odd) = number of odd sections ____________________ total number of sections
= 6 ___ 11
4 There are a total of 5 even sections The total
number of sections (odd and even) is 11
P(even) = number of even sections ____________________ total number of sections
= 5 ___ 11
5 The total number faces on a number cube is 6 and
rolling either a 3 or 4 is equal to 2 possibilities
P(rolling a 3 or 4) = number of sides with 3 or 4 ________________________ total number of sides on cube
= 2 __ 6 = 1 __
3
6 Sample answer No but it might be reasonably
close
7 Divide the number of ways the event can occur
by 20
Independent Practice
8 P(yellow) = number of yellow sections
_____________________ total number of sections
= 2 __ 6
= 1 __ 3 033 or 33
9 P(blue or green) = number of blue or green sections
___________________________ total number of sections
= 8 ___ 12
= 2 __ 3 067 or 67
10 P(cherry) = number of cherry cough drops
_________________________ total number of cough drops
= 4 ___ 14
= 2 __ 7 029 or 29
11 P(black card) = number of black cards __________________ total number of cards
= 26 ___ 52
= 1 __ 2 050 or 50
12 P(lime) = number of limes ________________________ total number of pieces of fruit
= 12 - 5 ______ 12
= 7 ___ 12
058 or 58
13 There are a total of 20 DVDs There are 12 DVDs
that are not comedies (5 science fiction plus
7 adventure)
P(not a comedy)
= number of DVDs which are not comedies _________________________________ total number of DVDs
= 5 + 7 _________
5 + 7 + 8 = 12 ___
20
= 3 __ 5 060 or 60
14 There are a total of 6 faces on a number cube There
are 2 faces (3 and 4) that are greater than 2 and
less than 5 which means 2 possibilities
P(greater than 2 and less than 5)
= number of sides with 3 and 4 ________________________ total number of sides on cube
= 2 __ 6
= 1 __ 3 033 or 33
15 9 represents the ways the event can occur
13 represents the number of equally likely outcomes
16 There are a total 16 coins and there are 6 coins that
are greater than 5 cents Therefore
P(coin worth more than 5 cents)
= number of coins worth more than 5 cents _________________________________ total number of coins
= 6 ___ 16
or 3 __ 8
The event is choosing a dime or a quarter and 6 of
the 16 coins are dimes or quarters
Focus on Higher Order Thinking
17 Sample answer Riley divided the number of petunia
seeds by the number of begonia seeds rather than
the total number of seeds The correct probability is
5 ______ 5 + 15
= 5 ___ 20
= 1 __ 4
times16
times16
times5
times5
Copyright copy by Houghton Mifflin Harcourt 85 All rights reserved
18 a The total number of students in the club is 35
There are 20 seventh graders Therefore
P(seventh grader) =
number of seventh graders
______________________ total number of students
= 20 ___ 35
= 4 __ 7
There are 15 eighth graders in the club Therefore
P(eighth grader) =
number of eighth graders
_____________________ total number of students
= 15 ___ 35
= 3 __ 7
Because 4 __ 7 gt 3 __
7 choosing a seventh grader is
more likely
b No each student has the same probability of
being selected 1 ___ 35
19 Sample answer The number of trials is twice the
number of marbles in the jar If the probabilities for
each color were the same the number of times that
color was drawn would be twice the number of
marbles with that color in the jar
20 Red The theoretical probability of choosing red is
P(red) = number of red marbles ___________________ total number of marbles
= 8 ___ 20
The experimental probability of choosing red is
14 ___ 40
or 7 ___ 20
Therefore the difference in the theoretical probability
and experimental probability of choosing a red
marble is 8 ___ 20
- 7 ___ 20
= 1 ___ 20
For blue the theoretical probability is
P(blue) = number of blue marbles ____________________ total number of marbles
= 10 ___ 20
The experimental probability is 16 ___ 40
= 8 ___ 20
Therefore the difference in the theoretical probability
and experimental probability of choosing a blue
marble is 10 ___ 20
- 8 ___ 20
= 2 ___ 20
= 1 ___ 10
For yellow the theoretical probability is
P(yellow) = number of yellow marbles
_____________________ total number of marbles
= 2 ___ 20
The experimental probability is 10 ___ 40
= 5 ___ 20
Therefore the difference in the theoretical probability
and experimental probability of choosing a yellow
marble is 5 ___ 20
- 2 ___ 20
= 3 ___ 20
Choosing a red marble has the smallest difference
between theoretical and experimental probability
LESSON 132
Your Turn
3 P(ham sandwich) =
number of combinations containing ham
_________________________________ total number of sandwich combinations
= 4 ___ 12
= 1 __ 3
4 P(sandwich containing Swiss cheese) =
number of combinations containing Swiss
__________________________________ total number of sandwich combinations
= 6 ___ 12
= 1 __ 2
5 To find the sample space make lists of possible
codes First make a list of codes that start with 0
and have 0 as the second digit
0 0 0 0
0 0 0 1
0 0 1 0
0 0 1 1
List of codes that start with 0 and have 1 as the
second digit
0 1 0 0
0 1 0 1
0 1 1 0
0 1 1 1
List of codes that start with 1 and have 0 as the
second digit
1 0 0 0
1 0 0 1
1 0 1 0
1 0 1 1
List of codes that start with 1 and have 1 as the
second digit
1 1 0 0
1 1 0 1
1 1 1 0
1 1 1 1
In total the number of possible outcomes is 16
There are six codes with exactly two 0s
0 0 1 1
0 1 0 1
0 1 1 0
1 0 0 1
1 0 1 0
1 1 0 0
This means the number of outcomes for a code with
exactly two 0s is 6 Therefore
P(Code exactly two 0s)
= number of favorable outcomes ____________________________ total number of possible outcomes
= 6 ___ 16
= 3 __ 8
Copyright copy by Houghton Mifflin Harcourt 86 All rights reserved
Guided Practice
1
1 2 3 4 5 6
11 sdot 1
= 1
1 sdot 2
= 2
1 sdot 3
= 3
1 sdot 4
= 4
1 sdot 5
= 5
1 sdot 6
= 6
22 sdot 1
= 2
2 sdot 2
= 4
2 sdot 3
= 6
2 sdot 4
= 8
2 sdot 5
= 10
2 sdot 6
= 12
33 sdot 1
= 3
3 sdot 2
= 6
3 sdot 3
= 9
3 sdot 4
= 12
3 sdot 5
= 15
3 sdot 6
= 18
44 sdot 1
= 4
4 sdot 2
= 8
4 sdot 3
= 12
4 sdot 4
= 16
4 sdot 5
= 20
4 sdot 6
= 24
55 sdot 1
= 5
5 sdot 2
= 10
5 sdot 3
= 15
5 sdot 4
= 20
5 sdot 5
= 25
5 sdot 6
= 30
66 sdot 1
= 6
6 sdot 2
= 12
6 sdot 3
= 18
6 sdot 4
= 24
6 sdot 5
= 30
6 sdot 6
= 36
2 There are 15 entries in the table that are multiples
of 4 The total number of entries in the table is 36
P(multiple of 4) = number of multiples of 4
_________________________ total number of entries in table
= 15 ___ 36
3 There are 23 entries in the table that are less than
13 The total number of entries is 36
P(less than 13) = number of entries less than 13 _________________________ total number of entries in table
= 23 ___ 36
4 H
HHH HHT
H
H
Coin 1
List
Coin 2
Coin 3 T
T
HTH HTT
H T
T
H
H T
THH THT
T
H T
TTH TTT
Coin 1
List
Coin 2
Coin 3
5 Count the total number of outcomes in the list 8
6 The only way to get three tails is TTT
7 P = number of outcomes with 3 tails __________________________ total number of outcomes
= 1 __ 8
8 There are 3 way(s) to obtain exactly two heads
HHT HTH THH
P = number of outcomes with exactly 2 heads
__________________________________ total number of possible outcomes
= 3 __ 8
9 You need to know the number of equally likely
outcomes in the sample space
Independent Practice
10
Checkered
Red
Checkered
Red
Blue
Black
Checkered
Red
Checkered
Red
Blue
Black
Checkered
Red
Checkered
Red
Blue
Black
Shirt Pants Shoes
Yellow
Red
Green
11 There are 6 combinations that include red shoes
The total number of combinations is 12 Therefore
P(red shoes) = number of combinations with red shoes ________________________________ total number of combinations
= 6 ___ 12
= 1 __ 2
12 There are four combinations that do not include red
Shirt Pants Shoes
Green Blue Checkered
Green Black Checkered
Yellow Blue Checkered
Yellow Black Checkered
P(no red) = number of outfits with no red _______________________ total number of outfits
= 4 ___ 12
= 1 __ 3
13 Let the other three band members be A B and C
The list of possible combinations is
Rhee Pamela
Rhee A
Rhee B
Rhee C
Pamela A
Pamela B
Pamela C
A B
A C
B C
There is a total of 10 combinations Of these only 1
has Rhee and Pamela so
P(Rhee and Pamela)
= Rhee and Pamela ________________________ total number of combinations
= 1 ___ 10
Copyright copy by Houghton Mifflin Harcourt 87 All rights reserved
14 The sample space can be found from adding all
possible combinations of the two numbers
1 2 3 4 5 6
11 + 1
= 2
1 + 2
= 3
1 + 3
= 4
1 + 4
= 5
1 + 5
= 6
1 + 6
= 7
22 + 1
= 3
2 + 2
= 4
2 + 3
= 5
2 + 4
= 6
2 + 5
= 7
2 + 6
= 8
33 + 1
= 4
3 + 2
= 5
3 + 3
= 6
3 + 4
= 7
3 + 5
= 8
3 + 6
= 9
44 + 1
= 5
4 + 2
= 6
4 + 3
= 7
4 + 4
= 8
4 + 5
= 9
4 + 6
= 10
55 + 1
= 6
5 + 2
= 7
5 + 3
= 8
5 + 4
= 9
5 + 5
= 10
5 + 6
= 11
66 + 1
= 7
6 + 2
= 8
6 + 3
= 9
6 + 4
= 10
6 + 5
= 11
6 + 6
= 12
There is a total of 36 possible sums Of these there
are 10 less than 6
P(sum is less than 6)
= number of sums less than 6 ____________________________ total number of possible outcomes
= 10 ___ 36
= 5 ___ 18
15 The sample space can be found from a tree
diagram
Khakis
Shorts
Shirt Pants Shoes
Collared Jeans
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Khakis
Shorts
T-shirt Jeans
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Total number of possible outcomes is 18 the
number of combinations which include jeans but
not sneakers is 4 Therefore
P(jeans but not sneakers)
= number of outfits with jeans no sneakers
_________________________________ total number of possible outcomes
= 4 ___ 18
= 2 __ 9
16 For each chair lift there are 6 possible trails So you
can multiply the number of choices of chair lifts (3)
by the number of trails (6)
17 Because there are 3 choices for the first item and
2 for the second there are 3 middot 2 = 6 possible
outcomes
18 There is a total of 30 possible shoe sizes Of these
the number of red shoes size 9 or larger is 7
Therefore
P(red and size 9 or larger) =
number of red shoes size 9 or larger
______________________________ total number of possible outcomes
= 7 ___ 30
Focus on Higher Order Thinking
19 Sondra orders one item from each column There
are 4 main dishes 4 vegetables and two sides so
the sample space is 4 sdot 4 sdot 2 = 32 The possible
outcomes of Sondrarsquos order are shown in the tree
diagram
Carrots
Sweet potato
Pasta
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Carrots
Sweet potato
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Carrots
Sweet potato
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Carrots
Sweet potato
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Salmon
Beef
Pork
Copyright copy by Houghton Mifflin Harcourt 88 All rights reserved
There are 8 total number of outcomes that include
salmon Therefore
Sondra P(salmon) = 8 ___ 32
= 1 __ 4
Gretchen orders a main dish and a vegetable There
are 4 main dishes and 4 vegetables so the sample
space is 4 sdot 4 = 16 The possible outcomes of
Gretchenrsquos order are shown in the tree diagram
Carrots
Sweet potato
PastaPeas
Asparagus
Carrots
Sweet potato
Peas
Asparagus
Carrots
Sweet potato
Peas
Asparagus
Carrots
Sweet potato
Peas
Asparagus
Salmon
Beef
Pork
There are 4 total number of outcomes that include
salmon Therefore
Gretchen (salmon) = 4 ___ 16
= 1 __ 4
Because the probabilities for Sondra and Gretchen
are equal neither has a greater probability of getting
a meal that includes salmon
20 a For possible two-digit codes consider first codes
that begin with 1 12 13 14 15 There are a total
of 4 possible codes This pattern continues for
each of the 5 digits and therefore we have a total
of 4 + 4 + 4 + 4 + 4 = 20 possible two-digit
codes (four codes each that begin with each of
the numbers 1ndash5)
For possible three-digit codes there are 12
possible codes that begin with 1 and so there are
12 possible codes for each of the numbers 1ndash5
making a total of 5 sdot 12 = 60 possible three-digit
codes
We can predict the number of possible five-digit
codes because we know there are 60 possible
three-digit codes and for each of these there are
only two digits that can be added to the end of
each code to make them five-digit codes These
are the digits that were not used in the three-digit
code and they have two possible orders for a
total of 60 sdot 2 = 120 possible five-digit codes
As a concrete example again consider the three-
digit codes that begin with 1 Tacking on the digits
which are not included in these three-digit codes
in both orders we have 12345 12354 12435
12453 12534 12543 13245 13254 13425
13452 13524 13542 14235 14253 14325
14352 14523 14532 15234 15243 15324
15342 15423 15432 If we do the same for the
three-digit codes beginning with 2ndash5 we will find
the 120 possible five-digit codes
b Now that the numbers can repeat for two-digit
codes take the 20 codes from before and add five
more codes (11 22 33 44 55) which makes a
total of 25 two-digit codes
For three-digit codes take the 60 codes from
before and add the 5 codes that have all digits
the same plus codes which have two digits
which are repeats To find these consider first the
codes with the first two digits the same 112 113
114 115 221 223 224 225 331 332 334 335
441 442 443 445 551 552 553 554 There
are 20 possible codes There are also 20 possible
codes with the last two digits the same Finally
consider the codes where the first and last digits
are the same For the repeated digit 1 we have
121 131 141 151 or 4 possible codes For each
of the digits 1ndash5 we have 4 possible codes for a
total of 4 sdot 5 = 20 Therefore the overall total
60 + 5 + 20 + 20 + 2 = 125 three-digit codes
To solve for how many possible 5 digit codes
there are notice a pattern in the codes For
two-digit codes the total possible codes is the
number of possible digits raised to the power
equal to the number of digits in the code or
52 = 25 For three-digit codes the number of
possible digits is the same and the number
of digits in the code is 3 so we have 53 = 125
Following this pattern there are 55 = 3125
possible five-digit codes
c Sample answer The better choice is to have the
digits repeat there are more unique codes with
repeated digits than without so it would be more
difficult for someone to guess a code for a locker
LESSON 133
Your Turn
1 There are 4 numbers less than 5 on a standard
number cube There are 6 possible outcomes so
P(number less than 5) = 4 __ 6 = 2 __
3
The number of events is 250 Therefore
P(number less than 5) times Number of events =
2 __ 3 times 250 = 16666 or about 167 times
Copyright copy by Houghton Mifflin Harcourt 89 All rights reserved
2 Set up a proportion The probability of getting
heads is 1 __ 2
1 __ 2 = x ___
18
1 __ 2 = x ___
18
x = 9
about 9 times
3 There are 17 total marbles and 8 are red Therefore
P(red) = 8 ___ 17
P(not red) = 1 - 8 ___ 17
= 9 ___ 17
It is more likely that he picks a marble that is not red
4 No Sample answer There is a total of 71 bills in the
bag and there are 11 bills worth $6 or more
Therefore
P(bill worth $6 or more) = 11 ___ 71
This is about a 15 probability so it is not likely you
will win enough to pay for your ticket
Guided Practice
1 An equally likely chance means that the probabilities
of being assigned to each crew are the same and
since there are three possibilities each has a
probability of 1 __ 3
Apartment 1 __ 3 Condo 1 __
3 House 1 __
3
The probability of being assigned to house crew is 1 __ 3
Set up and solve a proportion
1 __ 3 = x ___
18
1 __ 3 = x ___
18
x = 6
This means that Bob can expect to be assigned to
the house crew about 6 times out of 18
2 Since half of the ticket holders will receive a prize
this means that 300 divide 2 = 150 people will receive a
prize Because they are equally likely to receive one
of three prizes the probability of winning each of the
prizes is 1 __ 3 so the probability of winning a movie
ticket is 1 __ 3 The number of events is 150 Therefore
P(movie ticket) times Number of events = 1 __ 3 times 150 =
50 or 50 people are predicted to win a movie ticket
3 The total number of students in Mr Jawaranirsquos class
is 28 The probabilities of picking a student at
random with a certain eye color are
P(hazel) = 9 ___ 28
P(brown) = 10 ___ 28
P(blue) = 7 ___ 28
P(green) = 2 ___ 28
The event with the greatest probability is choosing a
person with brown eyes
4 You can find and compare probabilities Or you can
use probability to set up and solve a proportion or
an equation that relates the probability to the
unknown quantity
Independent Practice
5 The total number of marbles in the bag is 9 The
number of white or gray marbles is 3 Therefore
P(white or gray) = 3 __ 9 = 1 __
3
The number of events is 45 The equation to make a
prediction is then
P(white or gray) times Number of events = 1 __ 3 times 45 = 15
You can expect to get 15 white or gray marbles
6 A spinner which has an equal likelihood to land on
green or yellow means that the number of green and
yellow sections must be equal More likely to land on
red means that there must be more red sections
than yellow or green A Sample answer is
Y GRR
R R
RR
7 Because half the deck is red the probability of
drawing a red card is 1 __ 2 Because there are three
face cards for each of four suits there are 3 sdot 4 = 12
face cards and the probability of drawing a face
card is 12 ___ 52
To compare 1 __ 2 and 12 ___
52 use the least
common denominator of 52 so that 1 __ 2 = 26 ___
52 Given
that 12 ___ 52
lt 26 ___ 52
the probability of drawing a red card
is higher than of drawing a face card and it is more
likely that Dawn draws 2 red cards
8 The total number of aces in a deck is 4 Therefore
P(ace) = 4 ___ 52
= 1 ___ 13
The number of events is 39 The equation to make a
prediction is then
P(ace) middot Number of events = 1 ___ 13
times 39 = 3
He is predicted to draw an ace 3 times
9 The total number of red cards is 26 Therefore
P(red card) = 26 ___ 52
= 1 __ 2
The number of events is 1000 The equation to
make a prediction is then
P(red card) sdot Number of events = 1 __ 2 sdot 1000 = 500
The player is predicted to turn over a red card as the
first card 500 times
10 The sample space can be found from adding all
possible combinations of the two numbers
times6
times6
times9
times9
Copyright copy by Houghton Mifflin Harcourt 90 All rights reserved
1 2 3 4 5 6
1 2 3 4 5 6 7
2 3 4 5 6 7 8
3 4 5 6 7 8 9
4 5 6 7 8 9 10
5 6 7 8 9 10 11
6 7 8 9 10 11 12
There is a total of 36 possible sums Of these there
are 5 ways to roll a sum of 8 and 2 ways to roll a
sum of 11 The probabilities are
P(sum of 8) = 5 ___ 36
P(sum of 11) = 2 ___ 36
Because the probability of rolling a sum of 8 is
greater than that of rolling a sum of 11 ( 5 ___ 36
gt 2 ___ 36
) John is more likely to win
11 There are 5 possible numbers greater than 15 so
P(greater than 15) = 5 ___ 20
= 1 __ 4
The number of events is 180 The equation to make
a prediction is then
P(greater than 15) times Number of events =
1 __ 4 times 180 = 45
The chosen number will be greater than 15 for 45
days in the school year
12 The sample space for a standard cube is 36 and
there are 3 combinations that will have a sum of 4
so P(sum of 3) = 3 ___ 36
= 1 ___ 12
The number of events is 36 The equation to make a
prediction is then
P(sum of 3) times Number of events = 1 ___ 12
middot 36 = 3
Eben is predicted to roll a sum of 4 a total of 3 times
13 Sample answer No Every time you flip a coin the
probability of heads is 1 __ 2 but in reality you could flip
a coin many times and have it land heads up every
time
14 Sample answer A bag of marbles contains red and
blue marbles that are different sizes Since it is easy
to feel the difference between the two colors all of
the outcomes are not equally likely You cannot make
a prediction using theoretical probability
Focus on Higher Order Thinking
15 Sample answer What is the theoretical probability
that the coin lands on heads and you pick a marble
that is not green
The probability that the coin lands on heads is 1 __ 2
and the probability that the picked marble is not
green is 3 + 9 _________
3 + 8 + 9 = 12 ___
20 The product of these two
probabilities is 1 __ 2 times 12 ___
20 = 12 ___
40
16 Sample answer It is much more likely that he rolls a
5 or the coin lands on heads
The probability that Horace rolls a 5 and the coin
lands on heads is given by
P(5 and heads) = 1 __ 2 times 1 __
6 = 1 ___
12
In the case where Horace rolls a 5 or the coin lands
on heads the probability is given by
P(5 or heads) = 1 __ 6 + 1 __
2 - 1 __
6 times 1 __
2 = 7 ___
12
17 Yes but only theoretically because in reality nothing
can occur 05 times Sample answer The probability
that a flipped coin lands heads up is 1 __ 2 so in 75 flips
you can expect heads about 75 ___ 2 or 375 times
LESSON 134
Your Turn
1 Sample answer (data and percent will vary)
Trial Numbers generated 3 Males first
1 0 0 1 No
2 0 1 No
3 1 No
4 0 1 No
5 1 No
6 0 0 0 1 Yes
7 0 0 1 No
8 0 1 No
9 1 No
10 0 0 0 0 1 Yes
For these data the experimental probability that the
elephant gives birth to 3 male calves before having a
female calf is 2 ___ 10
or 20
2 Sample Answer (data and percent will vary)
Trial Numbers generated Correct answers
1 1 0 1 1 0 3
2 0 1 0 0 1 2
3 0 0 0 0 1 1
4 0 0 1 1 0 2
5 1 1 1 1 1 5
6 1 0 0 0 0 1
7 1 0 1 1 0 3
8 1 0 1 0 0 2
9 0 1 1 1 1 4
10 0 0 0 0 0 0
The experimental probability that he gets at least 2
questions right is 7 ___ 10
= 70
Copyright copy by Houghton Mifflin Harcourt 91 All rights reserved
Guided Practice
1 Since there is a 30 or 3 ___ 10
chance of drought let
the numbers 1 to 3 represent years with a drought
and the numbers 4 to 10 represent years without
a drought Since we are interested in the next 4
years perform multiple trials generating 4 random
numbers each time
2
Trial Numbers generated Drought years
1 10 3 5 1 2
2 10 4 6 5 0
3 3 2 10 3 3
4 2 10 4 4 1
5 7 3 6 3 2
6 8 4 8 5 0
7 6 2 2 8 2
8 6 5 2 4 1
9 2 2 3 2 4
10 6 3 1 5 2
3 In 8 out of the 10 trials there was a drought in at
least one of the years The experimental probability
of a drought in at least 1 of the next 4 years is
8 ___ 10
= 80
4 Sample answer Generate whole numbers from
1 to 4 Let 1 to 3 represent the event occurring
and 4 represent the event not occurring
Independent Practice
5 There is only 1 trial Trial 6 where it took exactly
4 contestants to get a winner
6 Since 1 out of 10 trials resulted in exactly
4 contestants the probability is 1 ___ 10
= 10
7 The trials for which at least 4 hurricanes struck are
Trials 2 and 7 or 2 out of 10 trials Therefore the
probability is 2 ___ 10
= 20
8 It is fewer than expected based on the simulation
9 It is unlikely but it is not impossible Each of the 3
numbers could be any number from 1 to 10
However there are 10 possible first numbers 10
possible second numbers and 10 possible third
numbers or a total of 1000 possible numbers when
generating three numbers from 1 to 10 The
probability of generating three 10s is 1 _____ 1000
10 Sample answer Use the numbers 1ndash5 where 1 2
and 3 represent packs which contain a player from
Erikarsquos favorite team Generate numbers randomly
and stop when you get a 1 2 or 3
Trial Numbers generated Number of Packs
1 3 1
2 4 2 2
3 2 1
4 1 1
5 2 1
6 4 5 3 2
7 4 2 2
8 4 5 2 1
9 4 4 3 3
10 5 1 2
The average number of packs she needs to buy is
1 + 2 + 1 + 1 + 1 + 2 + 2 + 1 + 3 + 2
_________________________________ 10
= 16 ___ 10
= 1 3 __ 5
packs Since she cannot buy a fraction of a pack
she must buy 2 packs
Focus on Higher Order Thinking
11 Sample answer The probability that she makes a
shot is 375 = 3 __ 8 Use the whole numbers from 1 to
8 with 1ndash3 representing shots she makes and 4ndash8
representing shots she misses For each new trial
generate 10 random numbers Count the number
of times 1 2 or 3 appears in each trial Divide the
number of trials in which she made at least 3 shots
by the total number of trials
12 Sample answer Their simulation was not
appropriate perhaps because they chose an
incorrect model You would expect there to have
been exactly 4 heads on more of the trials and
more variation in the number of heads in general
MODULE 13
Ready to Go On
1 P(red) = number of red marbles ___________________ total number of marbles
= 12 ___________________ 12 + 12 + 15 + 9 + 12
= 12 ___ 60
= 1 __ 5 020 or 20
2 P(diamond or spade)
= number of diamonds and spades
___________________________ total number of cards
= 13 + 13
_______ 52
= 26 ___ 52
= 1 __ 2 050 or 50
3 The most likely color of marble chosen is the most
common color in this case green
Copyright copy by Houghton Mifflin Harcourt 92 All rights reserved
4 In order to find the experimental probability count
the number of trials in which 1 occurs at least once
In this case there are 4 trials that generated a 1
Therefore the experimental probability is 4 ___ 10
or
40
5 Sample answer You can find the theoretical
probability of an event and then use it to make a
prediction by setting up a proportion
Copyright copy by Houghton Mifflin Harcourt 93 All rights reserved
Table of Contents
UNIT 6 Probability
Module 12Lesson 121 79
Lesson 122 81
Lesson 123 82
Lesson 124 82
Module 13Lesson 131 84
Lesson 132 86
Lesson 133 89
Lesson 134 91
Copyright copy by Houghton Mifflin Harcourt ivAll rights reserved
MODULE 1 Adding and Subtracting Integers
Are You Ready
1 an elevator ride down 27 stories -27
2 a $700 profit 700
3 46 degrees below zero -46
4 a gain of 12 yards 12
1 1
5 183
_ + 78
261
261
5 16 17
6 677
_ -288
389
389
1 1
7 1188
_ +902
2090
2090
1 15 14
8 2647
_ -1885
762
762
9
-8-10 -4-6 -2 2 4 6 8 100 10
-8-10 -4-6 -2 2 4 6 8 100 11
-8-10 -4-6 -2 2 4 6 8 100 12
-8-10 -4-6 -2 2 4 6 8 100
LESSON 11
Your Turn
7 -8 + ( -1 ) = -9
8 -3 + ( -7 ) = -10
9 -48 + ( -12 ) = -60
10 -32 + ( -38 ) = -70
11 109 + 191 = 300
12 -40 + ( -105 ) = -145
13 -150 + ( -1500 ) = -1650
14 -200 + ( -800 ) = -1000
Guided Practice
1 a There are 6 counters
b The red counters represent negative numbers
c -5 + ( -1 ) = -6
2 a There are 9 counters
b The red counters represent negative numbers
c -2 + ( -7 ) = -9
3 -5 + ( -2 ) = -7
-8-7-6-5 -2-1 0-4-3 4 -1 + ( -3 ) = -4
-5-4-3-2 1 2 3-1 0 5 -3 + ( -7 ) = -10
-10 -9-8-7 -4-3-2-6-5 6 -4 + ( -1 ) = -5
-5-4-3-2 1 2 3-1 0 7 -2 + ( -2 ) = -4
-5-4-3-2 1 2 3-1 0 8 -6 + ( -8 ) = -14
-16 -12 -4 0-8 9 -5 + ( -4 ) = -9
10 -1 + ( -10 ) = -11
11 -9 + ( -1 ) = -10
12 -90 + ( -20 ) = -110
13 -52 + ( -48 ) = -100
14 5 + ( 198 ) = 203
15 -4 + ( -5 ) + ( -6 ) = -15
16 -50 + ( -175 ) + ( -345 ) = -570
17 Add their absolute values Use the sign of the
integers as the sign of the sum
Solutions KeyThe Number System
UNIT
1
Copyright copy by Houghton Mifflin Harcourt 1 All rights reserved
Independent Practice
18 a
-4
-6
-8
-2
0
2
-5 + (-3)-3 + (-5)
b No -5 + ( -3 ) is -8 and -3 + ( -5 ) is also -8
19 -3 + ( -1 ) + ( -5 ) + ( -2 ) = -11 the golferrsquos total
score is -11
20 -3 + ( -6 ) = -9 the team lost a total of 9 yards
21 -14 + ( -5 ) + ( -12 ) + ( -23 ) = -54 The total
sack yardage was -54
22 a -10 + ( -8 ) = -18
b -6 + ( -2 ) = -8
c -18 lt -8 Jonestown
23 -100 + ( -75 ) + ( -85 ) = -260
Focus on Higher Order Thinking
24 a -25 + ( -45 ) + ( -75 ) = -145 Jan withdrew
$145
b -35 + ( -55 ) + ( -65 ) = -155 Julie withdrew
$155
c Sample answer $45 $55 and $65
25 It is easier to add -80 + ( -20 ) fi rst to get -100
and then add -173 to get -273
26 Disagree there are three pairs of positive integers
1 and 7 2 and 6 and 3 and 5 and three pairs of
negative integers -1 and -7 -2 and -6 -3 and
-5 The absolute value of the sum of any of these
six pairs is 8
LESSON 12
Your Turn
7 -51 + 23
ǀ -51 ǀ - ǀ 23 ǀ = 28
-51 + 23 = -28
8 10 + ( -18 )
ǀ -18 ǀ - ǀ 10 ǀ = 8
10 + ( -18 ) = -8
9 13 + ( -13 )
ǀ 13 ǀ - ǀ -13 ǀ = 0
10 25 + ( -26 )
ǀ -26 ǀ - ǀ 25 ǀ = 1
25 + ( -26 ) = -1
Guided Practice
1 9 + ( -3 ) = 6
2 3 4 5 8 9 106 7 2 -2 + 7 = 5
-3-2-1 0 3 4 51 2 3 -15 + 4 = -11
-18 -16 -12 -10-14 4 1 + ( -4 ) = -3
-5-4-3-2 1 2 3-1 0 5 -4 + 5 = 1
6 -6 + 6 = 0
7 2 + ( -5 ) = -3
8 -3 + 7 = 4
9 -8 + 14 = 6
10 7 + ( -5 ) = 2
11 5 + ( -21 ) = -16
12 14 + ( -14 ) = 0
13 0 + ( -5 ) = -5
14 32 + ( -8 ) = 24
15 To fi nd -4 + 2 start at -4 and move 2 units to the
right to -2 To fi nd the sum -4 + ( -2 ) start at -4
and move 2 units to the left to -6
Independent Practice
16 -15 + 71 = 56
17 -53 + 45 = -8
18 -79 + 79 = 0
19 -25 + 50 = 25
20 18 + ( -32 ) = -14
21 5 + ( -100 ) = -95
22 -12 + 8 + 7 = 3
23 -8 + ( -2 ) + 3 = -7
Copyright copy by Houghton Mifflin Harcourt 2 All rights reserved
24 15 + ( -15 ) + 200 = 200
25 -500 + ( -600 ) + 1200 = 100
26 9 + ( -22 ) = -13 the team lost 13 yards
27 -55 + 275 = 220 the teamrsquos profi t was $220
28 -47 + 47 = 0 Alexrsquos new balance is $0
29 Sample answer 10 and -2 and 12 and -4
30 Bart won Bartrsquos score = 123 + ( -180 ) = -57
points Samrsquos score = 185 + ( -255 ) = -70 points
-57 gt -70 so Bart has the greater score
Focus on Higher Order Thinking
31 Start at -4 and move 3 to the right to reach -1
Start at 3 and move 4 to the left to reach -1
The sums are equivalent by the Commutative
Property of Addition
32 The weight is dropped from 4 feet above the surface
Add -12 to represent the distance the weight falls
before it hits the bottom 4 + ( -12 ) = -8 The water
is 8 feet deep
33 Sample answer A model with more positive
counters than negative counters represents a sum of
two integers whose sum is positive
34 The sign of the other integer is positive and its value
is 6 or greater Sample explanation If you start at
-5 on a number line you have to move to the right 6
or more units to get a sum that is positive
LESSON 13
Your Turn
4 -7 - 2 = -7 + ( -2 )
-7 + ( -2 ) = -9
5 -1 - ( -3 ) = -1 + 3
-1 + 3 = 2
6 3 - 5 = 3 + ( -5 )
3 + ( -5 ) = -2
7 -8 - ( -4 ) = -8 + 4
-8 + 4 = -4
Guided Practice
1 5 - 8 = -3 Start with 5 positive counters
Add 3 zero pairs and remove 8 positive counters
3 negative counters are left so the difference is -3
2 -5 - ( -3 ) = -2 Start with 5 negative counters
and remove 3 negative counters 2 negative
counters are left so the difference is -2
3 -4 - 5 = -4 + ( -5 ) = -9
0-1-2-3-4-5-6-7-8-9 4 1 - 4 = 1 + -4 = -3
0 1 2 3 4-1-2-3-4 5 8 - 11 = 8 + ( -11 ) = -3
6 -3 - ( -5 ) = -3 + 5 = 2
7 15 - 21 = 15 + ( -21 ) = -6
8 -17 - 1 = -17 + ( -1 ) = -18
9 0 - ( -5 ) = 0 + 5 = 5
10 1 - ( -18 ) = 1 + 18 = 19
11 15 - 1 = 14
12 -3 - ( -45 ) = -3 + 45 = 42
13 19 - ( -19 ) = 19 + 19 = 38
14 -87 - ( -87 ) = -87 + 87 = 0
15 To subtract an integer add its opposite Sample
example 6 - 8 = 6 + ( -8 ) = -2
Independent Practice
16 To fi nd the change to Theorsquos account subtract the
initial balance -$4 from the fi nal balance $25
25 - ( -4 ) = 25 + 4 = 29
The overall change is $29
17 To fi nd the change in elevation subtract the
beginning elevation of -225 feet from the fi nal
elevation of -127 feet
-127 - ( -225 ) = -127 + 225 = 98
The change in elevation was 98 feet
18 Subtract the low temperature -2degF from the high
temperature 90degF
90 - ( -2 ) = 92
The difference between the high and low
temperatures is 92degF
19 Subtract Cheyennersquos score at the end of her turn
from her score at the start of her turn to fi nd the
change in Cheyennersquos score during her turn
-425 - ( -275 ) = -425 + 275 = -150
The change in Cheyennersquos score is -150 points
20 a Final temperature - initial temperature = change
in temperature
Gas A -8 - ( -21 ) = -8 + 21 = 13
13degC increase
Gas B 12 - ( -12 ) = 12 + 12 = 24
24degC increase
Gas C -15 - ( -19 ) = -15 + 19 = 4
4degC increase
b Negative the fi nal temperatures will be less than
the initial temperature because the gas is cooler
So the difference in temperatures will be negative
21 Diet Chow the catrsquos weight changed by
-8 + ( -18 ) = -26 ounces with Diet Chow and
3 + ( -19 ) = -16 ounces with Kitty Diet
Focus on Higher Order Thinking
22 Sample answer Susanne owed her sister $4 Then
she borrowed $10 more How much does Susanne
owe her sister in all
23 Tom found -11 - 4 instead of -11 - ( -4 ) To
subtract -4 he should add the opposite of -4
-11 + 4 = -7
Copyright copy by Houghton Mifflin Harcourt 3 All rights reserved
24 YouranswerwillbegreaterthantheintegeryoustartedwithbecausewhenyousubtractanegativeintegeryouadditsoppositeapositiveintegerForexample-5-( -3)=-5+3=-2-2gt-5
25 -16-21-26subtract5togetthenextterm
LESSON 14
Your Turn
1 Starts-Descends+Ascends-40-13+18=-53+18 =-3535feetbelowthecaveentrance
3 Usenegativeintegersforcheckamountsanduseapositiveintegerforamountdeposited-35+( -45)+180=-80+180 =100$100increase
4 JimJim-10-18+5-12=-10-18-12+5 =-( 10+18+12)+5 =-40+5 =-35Jimrestedat-35feet(35feetbelowthesurface)Carla0-20+5-18=0+5-20-18 =0+5-( 20+18) =5-38 =-33Carlarestedat-33feet(33feetbelowthesurface)
Guided Practice
1 -15+ 9- 12= -6- 12 =-1818feetbelowsealevel
2 -23+5-7=-18-7 =-25-25degF
3 50-40+87-30=10+87-30 =97-30 =6767points
4 -6+15+15=-6+30 =24
5 9- 4- 17= 9- 21 =-12
6 50-42+10=8+10 =18
7 6+13+7-5=19+2 =21
8 65+43-11=108-11 =97
9 -35-14+45+31=-49+76 =27
10 -12+6-4=-6-4 =-10-34-3+39=-37+39 = 2 -10lt2( -12+6-4)lt( -34-3+39)
11 21-3+8=18+8 =26-14+ 31- 6= 17- 6 =11 26gt11( 21-3+8)gt( -14+31-6)
12 SampleanswerAddandsubtractfromlefttoright-5+12+10-7=7+10-7=17-7=10
Independent Practice
13 a 5-1+6-1=9
b 9isapositivescoresoitisoverpar
c 9overparislessthan15overparYesCameronbeathisbestgolfscore
14 -6+14-11=-33feetunderground
15 TheCommutativePropertydoesnotapplytosubtraction3-6+5=2and3-5+6=4
16 a -350+275+70-50=-55Leersquosfinalscoreis-55points
b 45gt-55Barry
17 a 300to400
b 75+30-12+14-8+18-30=75+18+6-12=8787customersmustleavebetween400and500
18 100-18+22-53=51$51
19 45-17-22+18=24$24
20 Carlarsquosaccountdecreased$49-18+22-53=-49andLetarsquosaccountonlydecreased$21-17-22+18=-21Carlarsquosaccounthadthegreatestdecreaseinvalue
Focus on Higher Order Thinking
21 SampleanswerTimoweshisbrother1dollarHeborrows6moredollarsfromhisbrotherHepayshisbrotherback3dollarsHowmuchdoesTimstillowehisbrother-1-6+3=-4$4
22 Nothetotalamountshecouldpayherparentsis10+12+25=47and50-47=3Soshestillneeds$3
23 SampleanswerInthecaseinwhichthefirstnumberispositivethenthesumoftheabsolutevaluesoftheothertwonumbersmustbegreaterthanthevalueofthefirstnumberSampleexample13-5-10=-2ǀ 5ǀ+ǀ 10ǀ=15whichisgreaterthan13
MODULE 1
Ready to Go On
1 -8+( -6)=-14
2 -4+( -7)=-11
3 -9+( -12)=-21
CopyrightcopybyHoughtonMifflinHarcourt 4 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U1M01indd 4 103113 206 AM
4 5 + ( -2 )
ǀ 5 ǀ - ǀ -2 ǀ = 3
5 + ( -2 ) = 3
5 -8 + 4
ǀ -8 ǀ - ǀ 4 ǀ = 4
-8 + 4 = -4
6 15 + ( -8 )
ǀ 15 ǀ - ǀ -8 ǀ = 7
15 + ( -8 ) = 7
7 2 - 9 = 2 + ( -9 )
2 + ( -9 ) = -7
8 -3 - ( -4 ) = -3 + 4-3 + 4 = 1
9 11 - ( -12 ) = 11 + 12
11 + 12 = 23
10 -15 + 9 - 4 = -6 - 4
= -10
There are 10 fewer people on the bus
11 24 + 8 - 12 - 9 = 24 + 8 - ( 12 + 9 ) = 32 - 21
= 11
There are 11 cards left in the stack
12 Sample answer Tonya owes her sister $10 and
her friend $5 By how much will her savings change
after she pays them
-10 + ( -5 ) = -15 $15 decrease
Copyright copy by Houghton Mifflin Harcourt 5 All rights reserved
MODULE 2 Multiplying and Dividing Integers
Are You Ready
1 9 times 3 = 27
2 7 times 10 = 70
3 9 times 8 = 72
4 15 times 10 = 150
5 6 times 9 = 54
6 10 times 23 = 230
7 9 times 9 = 81
8 10 times 20 = 200
9 54 divide 9 = 6
10 42 divide 6 = 7
11 24 divide 3 = 8
12 64 divide 8 = 8
13 90 divide 10 = 9
14 56 divide 7 = 8
15 81 divide 9 = 9
16 110 divide 11 = 10
17 12 + 8 divide 212 + 4
16
18 15 - ( 4 + 3 ) times 2
15 - 7 times 2
15 - 14
1
19 18 - ( 8 - 5 ) 2
18 - ( 3 ) 2
18 - 9
9
20 6 + 7 times 3 - 5
6 + 21 - 5
27 - 5
22
21 9 + ( 2 2 + 3 ) 2 times 2
9 + ( 4 + 3 ) 2 times 2
9 + ( 7 ) 2 times 2
9 + 49 times 2
9 + 98
107
22 6 + 5 - 4 times 3 divide 2
6 + 5 - 12 divide 2
6 + 5 - 6
11 - 6
5
LESSON 21
Your Turn
4 Since the numbers have opposite signs the product
will be negative
ǀ -3 ǀ times ǀ 5 ǀ = 3 times 5 = 15
-3 ( 5 ) = -15
5 Since the numbers have the same sign the product
will be positive
ǀ -10 ǀ times ǀ -2 ǀ = 10 times 2 = 20
( -10 ) ( -2 ) = 20
6 One of the factors is 0 so the product is 0
0 ( -22 ) = 0
7 Since the numbers have the same sign the product
will be positive
8 ( 4 ) = 32
Guided Practice
1 -1 ( 9 ) = -9
2 14 ( -2 ) = -28
3 ( -9 ) ( -6 ) = 54
4 ( -2 ) ( 50 ) = -100
5 ( -4 ) ( 15 ) = -60
6 -18 ( 0 ) = 0
7 ( -7 ) ( -7 ) = 49
8 -15 ( 9 ) = -135
9 ( 8 ) ( -12 ) = -96
10 -3 ( -100 ) = 300
11 0 ( -153 ) = 0
12 -6 ( 32 ) = -192
13 7 ( -75 ) = -525 -$525
14 Start at zero and move 5 units to the left 3 times
3 ( -5 ) = -15 the team lost 15 yards
15 6 ( -2 ) = -12 -12degF
16 Multiply the absolute values of the integers If both
integers have the same sign the product is positive
If they have different signs the product is negative
Independent Practice
17 No her number line shows the correct result -6
but she modeled 2 ( -3 ) instead of -2 ( 3 )
18 2 ( -3 ) = -6 he went down 6 floors
19 5 ( -4 ) = -20 $20 decrease
20 Adam descended 5 feet a total of 5 times
5 ( -5 ) = -25 Adam is 25 feet below sea level
21 7 ( -6 ) = -42 the cost of the jeans decreased by
$42 over the 7 weeks
22 9 ( -6 ) = -54 -54 ( 2 ) = -108 Casey has $108
less in his savings
23 7 ( -8 ) = -56 7 ( -5 ) = -35
-56 + ( -35 ) = -91 The savings decreased by $91
24 Sample answer Dave plays a video game in which
he loses 20 points every time he misses a goal
He misses 8 goals 8 ( -20 ) = -160 he loses
160 points
Copyright copy by Houghton Mifflin Harcourt 6 All rights reserved
25 a 3 ( 3 ) ( -3 ) = 9 ( -3 ) = -27
b 3 ( -3 ) ( -3 ) = -9 ( -3 ) = 27
c -3 ( -3 ) ( -3 ) = 9 ( -3 ) = -27
d 3 ( 3 ) ( 3 ) ( -3 ) = 9 ( 3 ) ( -3 ) = 27 ( -3 ) = -81
e 3 ( 3 ) ( -3 ) ( -3 ) = 9 ( -3 ) ( -3 ) = -27 ( -3 ) = 81
f 3 ( -3 ) ( -3 ) ( -3 ) = -9 ( -3 ) ( -3 ) = 27 ( -3 ) = -81
g When a product of integers has an odd number of
negative factors like -3 ( -3 ) ( -3 ) = -27 and
3 ( 3 ) ( 3 ) ( -3 ) = -81 the sign of the product is
negative
When a product of integers has an even number
of negative factors like ( 3 ) ( -3 ) ( -3 ) = 27 and
3 ( 3 ) ( -3 ) ( -3 ) = 9 ( -3 ) ( -3 ) = 81 the sign of the
product is positive
Focus on Higher Order Thinking
26 -1 ( 3 ) ( 1 ) 1 ( -3 ) ( 1 ) -1 ( -3 ) ( -1 )
27 Unless one of the factors is 0 whenever the factors
have opposite signs the product will be less than or
equal to both of the two factors
28 The sign of the product is equal to the sign of the
integers The sign of the product of the first two
integers will always be positive Multiplying this
product by the remaining factor will make a positive
product if the factor is positive negative if it is
negative
LESSON 22
Your Turn
2 Since only the dividend is zero the quotient is 0
0 divide ( -6 ) = 0
3 Since the numbers have opposite signs the quotient
will be negative
38 divide ( -19 ) = -2
4 Since the numbers have the same sign the quotient
will be positive
-13 divide ( -1 ) = 13
5 Yolanda received the same number of penalties in
each game -25 divide ( -5 ) = 5 and -35 divide ( -7 ) = 5
Guided Practice
1 -14 ____ 2 = -7
2 21 divide ( -3 ) = -7
3 26 ____ -13
= -2
4 0 divide ( -4 ) = 0
5 -45 ____ -5 = 9
6 -30 divide ( 10 ) = -3
7 -11 ____ -1
= 11
8 -31 divide ( -31 ) = 1
9 0 ___ -7 = 0
10 -121 _____ -11
= 11
11 84 divide ( -7 ) = -12
12 500 ____ -25
= -20
13 -6 divide ( 0 ) = undefined any number divided by 0 is
undefined
14 -63 ____ -21
= 3
15 -40 divide ( 4 ) = -10 $10
16 -22 divide ( 11 ) = -2 2 points
17 -75 divide ( -15 ) = 5 5 targets
18 -99 divide ( -9 ) = 11 11 times
19 In both cases if the signs of the initial numbers are
the same the answer will be positive If the signs are
different the answer will be negative
Independent Practice
20 -24 divide ( 12 ) = -2 $2
21 Elisa made a greater number of withdrawals She
made -140 divide ( -20 ) = 7 withdrawals Francis made
-270 divide ( -45 ) = 6 withdrawals and 7 gt 6
22 a -2 - 10 = -12 the temperature decreased 12degF
b -12 divide ( 12 ) = -1 decreased by 1degF each hour
23 The first part the rate of change for the first part
is -200 ft _______ 10 min
= -20 ftmin and the rate of change for
the second part is -300 ft _______ 20 min
= -15 ftmin
20 ftmin gt 15 ftmin
24 Sample answer A football team lost 50 yards due to
5 penalties If the team lost the same number of
yards for each penalty what was the change in field
position for each penalty
25 Sample answer a = - 20 and b = 5 less than
-20 divide 5 = -4 and -20 times 5 = -100
-100 lt -4
26 True if the integers have the same sign the product
and quotient are positive if they have different signs
negative
27 False division by 0 is undefined for any dividend
Focus on Higher Order Thinking
28 a 100 divide 25 = 4 4 points
b -16 divide ( -4 ) = 4 Fred answered 4 questions
incorrectly
29 a divide ( -3 ) = 8
a = -24
8 divide b = -4
a divide b = -24 divide ( -2 ) = 12
Copyright copy by Houghton Mifflin Harcourt 7 All rights reserved
30 Dividing integers with the same sign results in a
positive number Since the original two integers are
negative the quotient is greater than both of these
integers
LESSON 23
Your Turn
1 Reggie earned 110 points
3 ( -30 ) + 200 = -90 + 200
= 110
2 -6 ( 13 ) - 21 = -78 - 21
= -99
4 ( -12 ) divide 6 + 2 = -2 + 2
= 0
5 -87 divide ( -3 ) -9 = 29 - 9
= 20
6 40 divide ( -5 ) + 30 = -8 + 30
= 22
7 -39 divide 3 -15 = -13 - 15
= -28
8 Amber moved 3 ( -3 ) + 5 = -4 or 4 places back
Will moved 2 ( -4 ) + 3 = -5 or 5 places back Will
moved further back
9 ( -10 ) divide 2 - 2 = -5 - 2 = -7
( -28 ) divide 4 + 1 = -7 + 1 = -6
10 42 divide ( -3 ) + 9 = -14 + 9 = -5
( -36 ) divide 9 - 2 = -4 - 2 = -6
Guided Practice
1 -6 ( -5 ) + 12 = 30 + 12
= 42
2 3 ( -6 ) - 3 = -18 - 3
= -21
3 -2 ( 8 ) + 7 = -16 + 7
= -9
4 4 ( -13 ) + 20 = -52 + 20
= -32
5 -4 ( 0 ) - 4 = 0 - 4
= -4
6 -3 ( -5 ) - 16 = 15 - 16
= -1
7 7 ( -5 ) + 20 = -35 + 20
= -15
15 dollars less
8 7 ( -10 ) + ( -100 ) = -70 + ( -100 )
= -170
170 fewer points
9 6 ( -4 ) + 10 = -24 + 10
= -14
Ned lost 14 points
10 4 ( -12 ) + 10 = -48 + 10
= -38
$38 less
11 -3 ( -2 ) + 3 = 6 + 3
= 9
3 ( -4 ) + 9 = -12 + 9
= -3
9 gt -3
-3 ( -2 ) + 3 gt 3 ( -4 ) + 9
12 -8 ( -2 ) -20 = 16 -20
= -4
3 ( -2 ) + 2 = - 6 + 2
= -4
-4 = -4
-8 ( -2 ) -20 = 3 ( -2 ) + 2
13 -7 ( 5 ) - 9 = -35 - 9
= -44
-3 ( 20 ) + 10 = -60 + 10
= -50
-44 gt -50
-7 ( 5 ) -9 gt -3 ( 20 ) + 10
14 -16 ( 0 ) -3 = 0 -3
= -3
-8 ( -2 ) -3 = 16 -3
= 13
-3 lt 13
-16 ( 0 ) -3 lt -8 ( -2 ) -3
15 A negative number usually represents a debt
payment or loss or a change that is a decrease
such as to a savings account
Independent Practice
16 -12 ( -3 ) + 7 = 36 + 7
= 43
17 -42 divide ( -6 ) + 5 -8 = 7 + 5 -8
= 12 -8
= 4
18 10 ( -60 ) -18 = -600 -18
= -618
19 ( -11 ) ( -7 ) + 5 - 82 = 77 + 5 - 82
= 82 - 82
= 0
20 35 divide ( -7 ) + 6 = -5 + 6
= 1
21 -13 ( -2 ) - 16 - 8 = 26 - 16 - 8
= 10 - 8
= 2
22 a 5 ( 2 ) -12 + 3 = 10 -12 + 3
= -2 + 3
= 1
b -3 ( 2 ) -1 + 6 + 7 = -6 -1 + 6 + 7
= -7 + 6 + 7
= -1 + 7
= 6
c Rose has more points than Lily so Rose won
the game
23 5 ( -4 ) -8 = -20 - 8 = -28
24 -36 divide ( -4 ) + 9 = 9 + 9 = 18
Copyright copy by Houghton Mifflin Harcourt 8 All rights reserved
25 a 4 ( -35 ) -9 = -140 -9
= -149
$149 less
b Yes $200 - $149 = $51 $51 gt $50 so Arleen
has enough money
26 a 2 ( -10 ) + 3 = -20 + 3= -17
b 7 + 2 + ( -7 ) = 2
c Warren since 2 is greater than -17
d Sample answer 2 of clubs 2 of spades
3 of spades king of diamonds 10 of clubs
7 of clubs
Focus on Higher Order Thinking
27 Sample answer Ann bought three shirts for $7 each
and a pair of pants for $10 Her mother gave her
$25 By how much did the amount of money Ann
had change
28 Disagree the quotient of two integers is positive if
the integers have the same sign So the first two
integers could have been negative integers
29 5 feet equals 60 inches so Lisa is holding the rock
60 inches above the waterrsquos surface The rock will
travel 4 times -5 = -20 inches or 20 inches below the
surface in 4 seconds 60 + 20 = 80 inches
MODULE 2
Ready to Go On
1 Since the numbers have opposite signs the product
will be negative
( -2 ) ( 3 ) = -6
2 Since the numbers have the same sign the product
will be positive
( -5 ) ( -7 ) = 35
3 Since the numbers have the opposite signs the
product will be negative
( 8 ) ( -11 ) = -88
4 ( -3 ) ( 2 ) ( -2 ) = ( -6 ) ( -2 ) = 12
5 5 ( -3 ) = -15 -15degC
6 -63 ____ 7 = -9
7 -15 ____ -3
= 5
8 0 ____ -15
= 0
9 96 ____ -12
= -8
10 -24 divide 6 = -4 -4 Ib
11 ( -4 ) ( 5 ) + 8 = -20 + 8
= -12
12 ( -3 ) ( -6 ) -7 = 18 -7
= 11
13 -27 ____ 9 - 11 = -3 - 11
= -14
14 -24 ____ -3
- ( -2 ) = 8 + 2
= 10
15 Sample answer Maurice lost 3 nickels in the laundry
and found 1 dime in the couch By how much did the
amount of money he had change
( -3 ) ( 5 ) + 10 = -15 + 10 = -5 He had $05 less
than before
Copyright copy by Houghton Mifflin Harcourt 9 All rights reserved
MODULE 3 Rational Numbers
Are You Ready
1 9 ___ 14
times 7 __ 6 =
3
2
9 ___ 14
times 7 __ 6 1
2
= 3 __ 4
2 3 __ 5 times 4 __
7 = 12 ___
35
3 11 ___ 8
times 10 ___ 33
= 1
4
11 ___ 8 times 10 ___
33 5
3
= 5 ___ 12
4 4 __ 9 times 3 =
3
4 __ 9 times 3 __
1 1
= 4 __ 3 or 1 1 __
3
5 1 __ 2 divide 1 __
4 = 1 __
2 times 4 __
1
=
1 1 __ 2 times 4 __
1 2
= 2 __ 1 = 2
6 3 __ 8 divide 13 ___
16 = 3 __
8 times 16 ___
13
= 1 3 __ 8 times 16 ___
13 2
= 6 ___ 13
7 2 __ 5 divide 14 ___
15 = 2 __
5 times 15 ___
14
= 1
1 2 __ 5 times 15 ___
14 3
7
= 3 __ 7
8 4 __ 9 divide 16 ___
27 = 4 __
9 times 27 ___
16
= 1
1 4 __ 9 times 27 ___
16 3
4
= 3 __ 4
9 3 __ 5 divide 5 __
6 = 3 __
5 times 6 __
5
= 18 ___ 25
10 1 __ 4 divide 23 ___
24 = 1 __
4 times 24 ___
23
= 1 1 __ 4 times 24 ___
23 6
= 6 ___ 23
11 6 divide 3 __ 5 = 6 __
1 times 5 __
3
= 2
6 __ 1 times 5 __
3 1
= 10 ___ 1 = 10
12 4 __ 5 divide 10 = 4 __
5 times 1 ___
10
= 2
4 __ 5 times 1 ___
10 5
= 2 ___ 25
13 21 - 6 divide 3
21 - 2
19
14 18 + ( 7 - 4 ) times 3
18 + 3 times 3
18 + 9
27
15 5 + ( 8 - 3 ) 2
5 + ( 5 ) 2
5 + 25
30
16 9 + 18 divide 3 + 10
9 + 6 + 10
15 + 10
25
17 60 - ( 3 - 1 ) 4 times 3
60 - ( 2 ) 4 times 3
60 - 16 times 3
60 - 48
12
18 10 - 16 divide 4 times 2 + 6
10 - 4 times 2 + 6
10 - 8 + 6
2 + 6
8
LESSON 31
Your Turn
0 _
571428
4 7 ⟌ _
40000000 Dividing into 40
_ -35
50
_ -49
10
_ -7
30
_ -28
20
_ -14
60
_ -56
40 Second appearance of 40
Because the number 40 repeats during the division
process the answer is a repeating decimal
-0 _
571428 or -0571428571428hellip
Copyright copy by Houghton Mifflin Harcourt 10 All rights reserved
0 _ 3
5 3 ⟌ _
100 Dividing into 10
_ -3
10 Second appearance of 10
Because the number 10 repeats during the division
process the answer is a repeating decimal 0 _ 3 or
0333hellip
045
6 20 ⟌ _
900
_ -8 0
1 00
_ -1 00
0
-045
7 -2 3 __ 4 = -thinsp 4 times 2 + 3
_________ 4 = -11 ____
4
275
4 ⟌ _
1100
_ -8
30
_ -28
20
_ -20
0
-275 terminating
8 7 1 __ 3 =
3 times 7 + 1 _________
3 = 22 ___
3
7 _ 3
3 ⟌ _
2200 Dividing into 10
_ -21
1 0 Second appearance of 10
Because the number 10 repeats during the division
process the answer is a repeating decimal 7 _ 3 or
7333hellip repeating
Guided Practice
06
1 5 ⟌ _
30
_ -3 0
0
06 terminating
089
2 100 ⟌ _
8900
_ -80 0
9 00
_ -9 00
0
-089 terminating
3 Simplify the fraction
4 ___ 12
= 4 times 1 _____ 4 times 3
= 1 __ 3
0 _ 3
3 ⟌ _
100 Dividing into 10
_ -3
10 Second appearance of 10
Because the number 10 repeats during the division
process the answer is a repeating decimal 0 _ 3 or
0333hellip repeating
0 _
25
4 99 ⟌ _
25000 Dividing into 25
_ -19 8
520
_ -495
25 Second appearance of 25
Because the number 25 repeats during the division
process the answer is a repeating decimal 0 _
25 or
02525hellip repeating
0 _ 7
5 9 ⟌ _
700 Dividing into 70
_ -63
70 Second appearance of 70
Because the number 70 repeats during the division
process the answer is a repeating decimal 0 _ 7 or
-0777hellip repeating
036
6 25 ⟌ _
900
_ -7 5
1 50
_ -1 50
0
-036 terminating
004
7 25 ⟌ _
100
_ -1 00
0
004 terminating
01420 _
45
8 176 ⟌ _
250000000
_ -17 6
7 40
_ -7 04
360
_ -352
80
_ -0
800 First appearance of 800
_ -704
960
_ -880
800 Second appearance of 800
Because the number 800 repeats during the
division process the answer is a repeating decimal
-01420 _
45 or -014204545hellip repeating
0012
9 1000 ⟌ _
12000
_ -10 00
2 000
_ -2 000
0
0012 terminating
Copyright copy by Houghton Mifflin Harcourt 11 All rights reserved
10 -11 1 __ 6 = -thinsp 6 times 11 + 1
_________ 6 = -67 ____
6
111 _ 6
6 ⟌ _
67000
_ -6
07
_ -6
1 0
_ -6
40 First appearance of 40
_ -36
40 Second appearance of 40
Because the number 40 repeats during the division
process the answer is a repeating decimal
- 67 ___ 6
-111 _ 6 or -111666hellip
11 2 9 ___ 10
= 10 times 2 + 9
__________ 10
= 29 ___ 10
29
10 ⟌ _
290
_ -20
9 0
_ -9 0
0
29 ___ 10
29
12 -8 23 ____ 100
= - 100 times 8 + 23
____________ 100
= -823 _____ 100
823
100 ⟌ _
82300
_ -800
23 0
_ -20 0
3 00
_ -3 00
0
-823 _____ 100
-823
13 7 3 ___ 15
= 15 times 7 + 3
__________ 15
= 108 ____ 15
72
15 ⟌ _
1080
_ -105
3 0
_ -3 0
0
108 ____ 15
72
14 54 3 ___ 11
= 11 times 54 + 3
__________ 11
= 597 ____ 11
54 _
27
11 ⟌ _
597000
_ -55
47
_ -44
30 First appearance of 30
_ -22
80
_ -77
30 Second appearance of 30
Because the number 30 repeats during the division
process the answer is a repeating decimal
597 ____ 11
54 _
27 or 542727hellip
15 -3 1 ___ 18
= -thinsp 18 times 3 + 1 __________
18 = -55 ____
18
30 _ 5
18 ⟌ _
55000
_ -54
1 0
_ -0
1 00 First appearance of 100
_ -90
100 Second appearance of 100
Because the number 100 repeats during the division
process the answer is a repeating decimal
-55 ____ 18
-30 _ 5 or -30555hellip
16 3 2 __ 3 =
3 times 3 + 2 _________
3 = 11 ___
3
3 _ 6
3 ⟌ _
1100
_ -9
2 0 First appearance of 20
_ -1 8
20 Second appearance of 20
Because the number 20 repeats during the division
process the answer is a repeating decimal
3 _ 6 or 3666hellip lbs of apples
17 -2 7 __ 8 = -
8 times 2 + 7 _________
8 = -23 ____
8
2875
8 ⟌ _
23000
_ -16
7 0
_ -6 4
60
_ -56
40
_ -40
0
-2875 lb
18 Disagree the definition of a rational number is a
number that can be written as the ratio of two
integers with a denominator not equal to zero and
3 ___ 47
is a well-defined ratio of two integers Tom did
not divide long enough to correctly determine that
the quotient is a repeating decimal
Copyright copy by Houghton Mifflin Harcourt 12 All rights reserved
Independent Practice
19 basketball players
_______________ football players
= 5 ___ 11
0 _
45
11 ⟌ _
5000 Dividing into 50
_ -4 4
60
_ -55
50 Second appearance of 50
Because the number 50 repeats during the division
process the answer is a repeating decimal
5 ___ 11
0 _
45 or 04545hellip repeating
20 hockey players
______________ lacrosse players
= 6 ___ 10
06
10 ⟌ _
60
_ -6 0
0
6 ___ 10
06 terminating
21 polo players
_____________ football players
= 4 ___ 11
036
11 ⟌ _
4000 Dividing into 40
_ -3 3
70
_ -66
40 Second appearance of 40
Because the number 40 repeats during the division
process the answer is a repeating decimal
4 ___ 11
0 _
36 or 03636hellip repeating
22 lacrosse players
______________ rugby players
= 10 ___ 15
= 5 times 2 _____ 5 times 3
= 2 __ 3
0 _ 6
3 ⟌ _
200 Dividing into 20
_ -1 8
20 Second appearances of 20
Because the number 20 repeats during the division
process the answer is a repeating decimal
10 ___ 15
0 _ 6 or 0666hellip repeating
23 football players
_____________ soccer players
= 11 ___ 11
= 1
11 ___ 11
1 terminating
24 Agree Sample answer There are 10 players on the
lacrosse team and dividing the number of any other
team by 10 will simply move the decimal point one
digit to the left Therefore the ratio of any team over
the lacrosse team will be a decimal that terminates
one place to the right of the decimal point
25 a -4 7 __ 8 = -thinsp 8 times 4 + 7
_________ 8 = - 39 ___
8
b 4875
8 ⟌ _
39000
_ -32
7 0
_ -6 4
60
_ -56
40
_ -40
0
-4875
c Sample answer 4 7 __ 8 is very close to 5 Therefore
You could estimate that the water level changes
by 5 inches per month The total change in the
water level at the end of the 3-month period
would be approximately -15 inches
26 integer terminating
27 Ben is taller because Benrsquos height of 5 5 ___ 16
is equal
to 85 ___ 16
or 53125 ft while Marcusrsquo height of 5 7 ___ 24
is
equal to 127 ____ 24
or 52916hellip ft
28 The first store has the better deal because they
offer 3 __ 4 or 075 of a bushel for $9 while the second
store offers only 2 __ 3 or 0666hellip of a bushel for $9
Focus on Higher Order Thinking
29 When the number 1 is the denominator in a fraction
its decimal form is simply the numerator In all other
cases concerning numbers 1 to 10 the division
process stops when either the remainder is 0 or
when the digits begin to repeat When the numbers
2 4 5 or 8 are in the denominator the decimal form
of a fraction will terminate When the numbers
3 6 7 or 9 are in the denominator the decimal form
of a fraction will be a repeating decimal
30 Julie made a higher score on her math test since
her math test score of 21 ___ 23
is equal to a repeating
decimal of approximately 0913 while her science
test score of 29 ___ 32
is equal to a terminating decimal of
090625
Sample answer The difference in scores cannot be
determined by simply comparing the numerators of
the two fractions because the denominators are not
the same For Julie to compare her scores she
needs to divide the denominators into their respec-
tive numerators until one of the quotients is found to
be greater than the other
31 No although the digits in the decimal appear to
follow a pattern a repeating decimal must have the
same combination of digits that repeat such as
0121212hellip
Copyright copy by Houghton Mifflin Harcourt 13 All rights reserved
LESSON 32
Your Turn
2
50 1 2 3 4
3 + 1 1 __ 2 = 4 1 __
2
3
0-7 -6 -5 -4 -3 -2 -1
-25 + ( -45 ) = -7
6
0 1 2-5-6-7-8 -4 -3-2-1
-8 + 5 = -3
7
10-1
1 __ 2 + ( - 3 __
4 ) = - 1 __
4
8
3 4 5 6 7 80 1 2-3-2-1
-1 + 7 = 6
9
3 4 50 1 2-5-4 -3-2-1
2 1 __ 2 + ( -2 1 __
2 ) = 0
10
3 4 50 1 2-5-4 -3-2-1
-45 + 45 = 0
11
1-1 0
3 __ 4 + ( - 3 __
4 ) = 0
The overall change is 0 cups
12 -15 + 35 + 2
-15 + 55
55 - 15
4
13 3 1 __ 4 + ( -2 ) + ( -2 1 __
4 )
3 1 __ 4 + ( -4 1 __
4 )
3 1 __ 4 - 4 1 __
4
-1
14 -275 + ( 325 ) + 5
-6 + 5
-1
15 15 + 8 + ( -3 )
23 + 3
20
Guided Practice
1
3 4 50 1 2-5-4 -3-2-1
-3 + ( -15 ) = -45
2
0 54321-5-4-3-2-1
15 + 35 = 5
3
0 105-1 -05
1 __ 4 + 1 __
2 = 3 __
4
4
0 54321-5-4-3-2-1
-1 1 __ 2 + ( -1 1 __
2 ) = -3
5
0 54321-5-4-3-2-1
3 + ( -5 ) = -2
6
0 54321-5-4-3-2-1
-15 + 4 = 25
7 -2150 + 2150 = 0 $0
8 -874 + 874 = 0 $0
9 275 + ( -2 ) + ( -525 )
275 + ( -725 )
- ( 725 - 275 )
-45
10 -3 + 1 1 __ 2 + 2 1 __
2 = -3 + 4 = 1
11 124 + 92 + 1
-124 + 102
- ( 124 - 102 )
-22
12 -12 + 8 +13
-12 + 21
21 - 12
9
13 45 + ( -12 ) + ( -45 )
45 + ( -45 ) + ( -12 )
0 + ( -12 )
-12
14 1 __ 4 + ( - 3 __
4 ) = - ( 3 __
4 - 1 __
4 ) = - 2 __
4 = - 1 __
2
Copyright copy by Houghton Mifflin Harcourt 14 All rights reserved
15 -4 1 __ 2 + 2 = - ( 4 1 __
2 - 2 ) = -2 1 __
2
16 -8 + ( -1 1 __ 8 ) = -9 1 __
8
17 Start at -4 and move 6 units to the right
The sum is 2
Independent Practice
18 The opposite of +19 is -19
19 -$225 + $1500 = $1500 - $225 = $1275
20 -3525 m + ( -85 ) = -4375 m
21 4 3 __ 4 mi + ( -3 1 __
4 mi ) = 1 2 __
4 mi = 1 1 __
2 mi
22 1635 m + ( -05 m ) = 163 m above sea level
23 30 + 15 - 25 = 45 - 25 = 20 pts
24 January
Income - Expenses
$1205 - $129060
- ( $129060 - $1205 ) -$8560
February
Income - Expenses
$1183 - $134544
-($134544 - $1183)
-$16244
Kameh lost $8560 in January and $16244 in
February
25 June
Income - Expenses
$2413 - $210623
$30677
July
Income - Expenses
$2260 - $195850
$30150
August
Income - Expenses
$2183 - $184512
$33788
Kameh gained $30677 in June $30150 in July and
$33788 in August
26 First sum all the values in the Income column Then
sum all the values in the Expenses column Subtract
the total expenses from the total income Finally add
the $250 profit from December (not shown in the
table) to find the total profit or loss of the bakery by
the end of August
Income = $1205 + $1183 + $1664 + $2413
$2260 + $2183 = $10908
Expenses = $129060 + $134544 + $1664 +$210623 + $195850 + $184512
= $1020989
Profit = $10908 - $1020989 + $250
= $94811
27 -2 is the opposite or additive inverse of 2
28 a 7 ( 10 ) + 3 ( -15 ) = 70 - 45 = 25 pts
b 2 ( 10 ) + 8 ( -15 ) = 20 - 120 = -100 pts
c 10 + 10 + 10 + 10 + 10 + ( ndash15 ) + ( ndash15 ) + ( ndash15 ) +
( ndash15 ) + ( ndash15 ) or 5 ( 10 ) + 5 ( ndash15 )
Focus on Higher Order Thinking
29 The sum of two negative rational numbers is always
negative The sum of a negative rational number and
a positive rational number is negative if the absolute
value of the negative number is greater than that of
the positive number
30 Sample answer The student might have subtracted
the absolute values of the numbers
31 Yes 55 and -55 are opposites and -23 and 23
are opposites so the expression [ 55 + ( -23 ) ] +
( -55 + 23 ) can be viewed as the sum of two
opposites which is always 0
LESSON 33
Your Turn
1
-9 -8 -7 -6 -5 -4
-65 - 2 = -85
2
42 30-1 1
1 1 __ 2 - 2 = - 1 __
2
3
-10-9 -8 -7 -6 -5 -4 -3 -2 -1 0
-225 - 55 = -775
6
1 2-1 0
025 - ( -150 ) = 175
7
1-1 0
- 1 __ 2 - ( - 3 __
4 ) = 1 __
4
Guided Practice
1
1312111098765 14 15
5 - ( -8 ) = 13
2
-9 -8 -7 -6 -5 -4 -3
3 1 __ 2 - 4 1 __
2 = -8
Copyright copy by Houghton Mifflin Harcourt 15 All rights reserved
3
-15 -13 -11 -9 -5-7
-7 - 4 = -11
4
-6 -5 -4 -3 -2 -1 0 1
-05 - 35 = -4
5 -14 - 22 = -36
6 -125 - ( -48 )
-125 + 48
- ( 125 - 48 )
-77
7 1 __ 3 - ( - 2 __
3 ) = 1 __
3 + 2 __
3 = 1
8 65 - ( -14 ) = 65 + 14 = 79
9 - 2 __ 9
- ( -3 )
- 2 __ 9
+ 3
3 - 2 __ 9
2 9 __ 9 - 2 __
9
2 7 __ 9
10 24 3 __ 8
- ( -54 1 __ 8 )
24 3 __ 8
+ 54 1 __ 8
78 4 __ 8
78 1 __ 2
11 -1 m + ( 105 m ) = -15 m
15 m below sea level
12 -12 1 __ 2 + ( -5 ) = -17 1 __
2
17 1 __ 2
or 175 yards
13 Change in height = Starting height - ending height
533 ft - ( -10 ft ) = 533 ft + 10 ft = 543 ft
14 -4500 + (-3015) = -7515 $7515
15 Explain that she is supposed to start at positive 4 on
the number line then move 12 places to the left
because she is subtracting a positive number She
will end on the number -8 which is the answer
Independent Practice
16 -126degC - 75degC = -201degC
17 -2565 ft - 165 ft + 1245 ft = -297 ft
The diver is 297 ft below the surface
18 -9500 ft - ( -26000 ft ) = 16500 ft
19 29035 ft - ( -36198 ft ) = 65233 ft
70000 ft - ( -26000 ft ) = 96000 ft
Mars has the greater difference by
96000 ft - ( 65233 ft ) = 30767 ft
20 a -5degF + 78degF - 32degF
b 78degF - 32degF
c -5degF + 78degF - 32degF 78degF - 5degF - 32degF 78degF - 37degF = 41degF 78degF - 32degF = 46degF
21 a -$1258 + ( -$3072 ) = -$4330
b -$4330 + ( -$25 ) = -$6830
c $6830 since -$6830 + $6830 = 0
22 a No 4 times 52 in = 208 in
b 208 in - 20 in = 08 in more needed
23 a 5 ft - 72 ft + 22 ft
b 5 ft - 72 ft + 22 ft
5 ft + 22 ft - 72 ft
72 ft - 72 ft
= 0 ft because he moved the same distance
backward and forward
24 a Yes
$425 + $089 + $1099
= $1613 lt $20
b $20 - $1613 = $387 left over
Focus on Higher Order Thinking
25 The Commutative Property of Addition (CPA) could
be used to simplify the two terms that already have
a common denominator first
- 7 ___ 16
- 1 __ 4 - 5 ___
16 = ( - 7 ___
16 ) + ( - 1 __
4 ) + ( - 5 ___
16 )
( - 7 ___ 16
) + ( - 5 ___ 16
) + ( - 1 __ 4 ) by CPA
( -7 + ( -5 ) __________
16 ) + ( - 1 __
4 )
( -12 ____ 16
) + ( - 1 __ 4 )
( - 4 times 3 _____ 4 times 4
) + ( - 1 __ 4 )
( - 3 __ 4 ) + ( - 1 __
4 )
( -3 + ( -1 ) __________
4 )
( -4 ___ 4 ) = -1
26 Lowest -225degF + ( -12degF ) = -345degFHighest -195degF + ( -12degF ) = -315degF
27 Sample answer Yes because both numbers are
rational numbers each can be written as the ratio of
two integers for example a __ b
and c __ d
Both fractions
could be given a common denominator and then
one could then be subtracted from the other The
result would be a fraction which is a rational number
28 No Sample answer It is possible for the
difference of two negative numbers to be negative
[ -4 - ( -1 ) = -3 ] but it is also possible for the
difference to be positive [ -5 - ( -8 ) = 3 ]
Copyright copy by Houghton Mifflin Harcourt 16 All rights reserved
LESSON 34
Your Turn
1
-8 -7 -6 -5 -2 -1 0-4 -3
2 ( -35 ) = -7
2
-2 -1 0 1 2 3 4-4 -3
-3 ( -125 ) = 375
4 ( - 3 __ 4 ) ( - 4 __
7 ) ( - 2 __
3 ) = -
13 times 41 times 2 __________ 14 times 7 times 31
= - 1 times 1 times 2 _________ 1 times 7 times 1
= - 2 __ 7
5 ( - 2 __ 3 ) ( - 3 __
4 ) ( 4 __
5 ) = 2 times 31 times 41
__________ 13 times 41 times 5
= 2 times 1 times 1 _________ 1 times 1 times 5
= 2 __ 5
6 ( 2 __ 3 ) ( - 9 ___
10 ) ( 5 __
6 ) = -
12 times 93 times 51
____________ 13 times 210 times 63
= - 1 times 31 times 1 __________ 1 times 2 times 31
= - 1 __ 2
Guided Practice
1
-5 -2 -1 0-4 -3
5 ( - 2 __ 3 ) = 5 __
1 times ( - 2 __
3 )
= - 5 times 2 _____ 1 times 3
= - 10 ___ 3
= -3 1 __ 3
2
-1 -05 0-2 -15
3 ( - 1 __ 4 ) = 3 __
1 times - 1 __
4
= - 3 times 1 _____ 1 times 4
= - 3 __ 4
3
0 1 2-2 -1
-3 ( - 4 __ 7 ) = 3 __
1 times 4 __
7
= 3 times 4 _____ 1 times 7
= 12 ___ 7
= 1 5 __ 7
4
-2 -1 0 1 2 3 4-4 -3
- 3 __ 4 ( -4 ) = 3 __
4 times 4 __
1
= 3 times 41
______ 14 times 1
= 3 times 1 _____ 1 times 1
= 3 __ 1
= 3
5 4 ( -3 ) = -12
6 -18 ( 5 ) = -9
7 -2 ( -34 ) = 68
8 054 ( 8 ) = 432
9 -5 ( -12 ) = 6
10 -24 ( 3 ) = -72
11 1 __ 2 times 2 __
3 times 3 __
4 = ( 1 times 21
______ 12 times 3
) ( 3 __ 4 )
= ( 1 __ 3 ) ( 3 __
4 )
= 1
1 __ 3 times 3 __
4 1
= 1 __ 4
12 - 4 __ 7 ( -thinsp 3 __
5 ) ( - 7 __
3 ) = ( - 4 times 3 _____
7 times 5 ) ( - 7 __
3 )
= 12 ___ 35
( - 7 __ 3 )
= - 4
5 12 times 7 ______ 35 times 3
1
1
= - 4 times 1 _____ 5 times 1
= - 4 __ 5
13 ( - 1 __ 8 ) times 5 times 2 __
3 = ( - 1 __
8 ) times 5 __
1 times 2 __
3
= - 1 times 5 times 21
__________ 48 times 1 times 3
= - 1 times 5 times 1 _________ 4 times 1 times 3
= - 5 ___ 12
Copyright copy by Houghton Mifflin Harcourt 17 All rights reserved
14 ( - 2 __ 3
) ( 1 __ 2 ) ( - 6 __
7 ) = 2 times 1 times 62
__________ 13 times 21 times 7
= 1 times 1 times 2 _________ 1 times 1 times 7
= 2 __ 7
15 4 ( -350 ) = -14 or a $14 change in price
16 18 ( -100 ) = -1800 or a $1800 change
17 Sample answer Count the number of times there is
a negative sign If there are an even number of
negative signs then the final product will be positive
If there is an odd number of negative signs then the
final product will be negative
Independent Practice
18 a 6 ( -1998 ) Note that the change in her bank
account balance does not depend on the initial
amount
b 200 + 6 ( -1998 )
= 200 - 11988
= 8012 $8012
19 Sample answer Start at 0 then move 15 units to
the left (because 15 is negative in this case) 4 times
You are now on -6 Then because 4 is negative in
this case we want to move to the opposite of -6
which is 6
20 8 ( -3 1 __ 4 ) = -8 ( 13 ___
4 )
= - 1
8 __ 1 times 13 ___
4 1
= - 2 times 13 ______ 1 times 1
= - 26 ___ 1
-26 min At the same rate the watch will be
26 minutes behind after 8 weeks
21 3 ( -325 ) = -975 ft The change in depth is -975 ft
Therefore the submarine will be 975 below sea level
(below the surface)
22 5 + ( -3 ) ( 15 )
= 5 + ( -45 )
= 05 cups left
23 Matthew is incorrect Sample answer Matthew
should have said that multiplying by two negatives
is like multiplying the opposite of a positive twice
The opposite of a positive twice brings you back to
a positive
24 5 ( -15 ) = -75 min Therefore she will be late by
75 minutes or 1 hour and 15 minutes
25 Total score is
2 times ( 6 ) + 16 times ( 05 )
+ 7 times ( -05 ) + 2 times ( -15 )
= 12 + 8 - 35 - 3
= 20 - 65
= 135 pts
Focus on Higher Order Thinking
26 Temperature at 5 kilometers
= Temp at ground level + change in temp
= 12 + 5 ( -68 )
= 12 + ( -34 )
= -22degC
27 a b c d
+ + + +
+ + - +
+ - + +
- + + +
- - - +
- - + -
- + - -
+ - - -
28 If the product of two numbers is positive then the two
numbers must have the same sign either they are
both positive or both negative If the sum is negative
then at least one of the numbers must be negative
Therefore the two integers that add to -7 and multiply
to 12 must both be negative The negative paired
factors of 12 are -1 and -12 -2 and -6 and -3
and -4 Of those choices only -3 and -4 add to -7
LESSON 35
Your Turn
3 28 ___ -4
= - 28 ___ 4 = -07
4 -664 ______ -04
= 664 ____ 04
= 166
5 - 55 ___ 05
= - 55 ___ 5 = -11
6 -4256 _______ 112
= -38
The divers change in elevation was -38 feet
per minute
7 - 5 __
8 ___
- 6 __ 7 = - 5 __
8 divide - 6 __
7
= - 5 __ 8 times - 7 __
6
= 35 ___ 48
8 - 5 ___
12 ____
2 __ 3 = - 5 ___
12 divide 2 __
3
= - 5 ___ 12
times 3 __ 2
= - 15 ___ 24
= - 5 __ 8
Copyright copy by Houghton Mifflin Harcourt 18 All rights reserved
9 -4__5
___1__2 =-4__5divide1__
2
=-4__5times2__1
=-8__5
=-13__5
Guided Practice
1 072_____-09=-72___
9 =-08
2 -1__5
___7__5 =-1__
15times5
1__
7=-1times1_____
1times7=-1__7
3 56___-7=-56___7=-8
4 251____4 divide(-3__
8)=251____
4 times-8__
3
=-251times82________
14times3
=-251times2_______1times3
=-502____3
5 75____-1__5
=-75___1times5__
1=-75times5______
1times1=-375
6 -91____-13=91___
13=7
7 -3__7
___9__4 =-
13__7times4__93
=-1times4_____7times3
=-4___21
8 - 12____003
=-1200_____
3 =-400
9 =changeinwaterlevel_________________
changeindays
=-35L______4day
=-0875 L____day
or-0875Lperday
10 =totalchangeinprice_________________
changeindays
=-$4575________5day
=-$915perdayonaverage
11 totalchangeinaltitude___________________
numberofminutes
=-044mi________08min
=-44mi______8min
=-055mileperminute
12 FirstfindthesignofthenumeratorwhichisnegativeNextfindthesignofthedenominatorwhichisnegativeThereforethequotientwillbepositivebecausethenumeratoranddenominatorbothhavethesamesign
Independent Practice
13 5___-2__
8=-5__
1times8__
24
1=-5times4_____
1times1=-20
14 51__3divide(-11__
2)
=-3times5+1_________3 divide2times1+1_________
2
=-16___3divide3__
2
=-16___3times2__
3
=-16times2______3times3
=-32___9
15 -120_____-6 =120____
6 =20
16 -4__5
___-2__
3=
24__5times3__
21=2times3_____
5times1=6__
5
17 103divide(-103)=-103____1 times 1____
103
=-103times1________1times103
=-103____103
=-103____103
=-01
18 -04_____80
=-04___80
=-0005
19 1divide9__5=1__
1times5__
9=5__
9
20 -1___4 ___
23___24
=-1__
14times246
___23
=-1times6______1times23
=-6___23
21 -1035_______-23 =1035_____
23 =45
22 totalhours_____________numberofdays
= 21h______7days
=3 h____day
totaltimelost3 h____day
times3days=9hours
Alexusuallyruns21hoursperweeksodivideby7tofindthatheruns3hoursperdaySinceheisunabletorunfor3dayshistimeisdecreasedby9hoursor-9
23 totalchangeinyards
_________________numberofruns
=-4times15+3___________4 times1__
9
yd___run
=-763___4 times1__
91yd
___run
=-153__
4yd______
9runs
=-153__4times1__
9
yd___run
=-7__4or-13__
4yardsperrun
CopyrightcopybyHoughtonMifflinHarcourt 19 Allrightsreserved
DO NOT EDIT--Changes must be made through File info CorrectionKey=B
7_MCABESK207233_U1M03indd 19 103113 759 PM
24 -121degC + ( -78degC ) + ( -143degC ) + ( -72degC )
_____________________________________ 4
= 414degC ______ 4
= -1035degC per day
25 a total profit
_____________ number of days
= $1750
______ 7 days
= $250 per day
b $150
_____ day
times 7 days = $1050
c total change
_____________ number of days
= - $490
______ 7 days
= -$70 per day
26 total meters descended ___________________ number of seconds
= 996 m ______ 12 s
= 83 ms
27 When converting the division equation into a
multiplication problem he forgot to multiply by the
reciprocal and instead multiplied by the fraction in
the denominator The correct answer is given by
- 3 __
4 ___
4 __ 3
= - 3 __
4 times 3 __
4 = - 9 ___
16
28 -37 m _______ year times ( 2012 ndash 1995 ) years
= -37 m _______ year times 17 years
= -629 m
Focus on Higher Order Thinking
29 Sample answer The average change in temperature
per day would be given by -85 divide 15 if the
temperature were to drop of 85degF over 15 days
-85degF divide 15 d
= - 1785 ____ 315
degF __ d
= - 17 ___ 3 degF __
d or -5 2 __
3 degF __
d asymp -567 degF __
d
On average the temperature changed by -567degF
every day
30 Yes By definition the result of dividing an integer by
a non-zero integer is a rational number
31 Yes The result of dividing an integer by a non-zero
integer always results in a rational number by
definition
LESSON 36
Your Turn
1 Find the total commercial time
3 times 2 1 __ 2 = 7 1 __
2
Find the total entertainment time
30 - 7 1 __ 2 = 22 1 __
2
Find the length of each entertainment segment
22 1 __ 2 divide 4 = 5 5 __
8
Each entertainment segment is 5 5 __ 8 minutes long
2 Find the number of cups of sugar in the bag
454 divide 48 asymp 95
Find the number of 3 __ 4 -cup portions in the bag
95 divide 075 asymp 127
12 batches can be made from the bag of sugar
Find the cost of 1 batch
349 divide 12 asymp 029
The cost of the sugar is $029 per batch
3 Convert the percent to a decimal
12 3 __ 5 = 126
= 0126
Find the worth after 1 year
750 times 0126 = 945
750 + 945 = 8445
Find the worth after 2 years
8445 times 0126 asymp 10641
8445 + 10641 = 95091
Find the worth after 3 years
95091 times 0126 asymp 11981
95091 + 11981 = 107072
The stock is worth $107072
Guided Practice
1 45h times 3 1 __ 5 or 32 miles per hour = 144 miles
144 miles divide 3 3 __ 5 or 36 miles per hour = 4 hours
2 2568 inches times -002375 asymp -061 inches
2568 inches - 061 asymp 2507 inches
3 Sample answer Using a calculator to solve a
problem that involves complicated arithmetic can
help you avoid errors It can also help you to check
solutions to any problems you solved by hand
Independent Practice
4 Find the total weight
78 times 3 = 234
Find the weight each climber carries
234 divide 4 = 585
Each climber carries 585 kg
Copyright copy by Houghton Mifflin Harcourt 20 All rights reserved
5 Find the available width on the page
12 - 3 1 __ 2 = 8 1 __
2
Find half the width
8 1 __ 2 divide 2 = 4 1 __
4
He should put the picture 4 1 __ 4 inches from each side
of the page
6 Find the amount of cereal needed for all the children
11 times 1 __ 3 = 3 2 __
3
10 times 3 __ 4 = 7 1 __
2
3 2 __ 3 + 7 1 __
2 = 11 1 __
6
Compare the total needed with the amount in the
box
11 1 __ 6 lt 12
Yes there is enough Oaties for all the children The
amount needed is 11 1 __ 6 cups and that is less than the
amount in the box 12 cups
7 Find half of the distance that the referee walked
41 3 __ 4 divide 2 = 20 7 __
8
Find how far that distance is from the goal line
50 - 20 7 __ 8 = 29 1 __
8
The referee is 29 1 __ 8 feet from the nearest goal line
8 Donovanrsquos score was 39 ___ 50
= 78 Marcirsquos score was
( 78 + 10 ) = 88
9 Find the number Marci answered correctly
88 = 88 ____ 100
= 44 ___ 50
Find how many more that Marci answered than
Donovan
44 - 39 = 5
Marcie answered 5 more questions correctly than
Donovan
10 Sample answer Donovan got about 40 out of 50
questions right or about 80 Since Marci scored
10 more that is about 90 90 times 50 is 45 So
Marci answered about 45 - 40 or 5 more questions
correctly than Donovan
11 Yes -075 is a reasonable estimate
19 ___ 37
is about 1 __ 2 and 143 is about 15 and
15 times ( - 1 __ 2 ) = -075
12 Sample answer approximately -07343 Use a
calculator Divide -19 by 37 multiply the quotient by
143 then round the product
13 Sample answer Yes -07343 asymp - 075
Focus on Higher Order Thinking
14 Find the time of the descent
-79 9 ___ 10
divide ( -188 ) = 425
Find the time for the ascent
19 1 __ 8 - 1275 - 425 = 2 1 __
8
Find the distance of the ascent
-28 9 ___ 10
- ( -79 9 ___ 10
) = 51
Find the rate of the ascent
51 divide 2 1 __ 8 = 24
The diverrsquos rate of change in elevation during the
ascent was 24 ftmin
15 Sample answer
(1) Convert the mixed number 27 3 __ 5 to the decimal
276 find the sum of 276 and 159 then multiply
the result by 037
(2) Convert the mixed number 27 3 __ 5 to the decimal
276 Then use the Distributive Property so that
(276 + 159)037 = (276)(037) + (159)(037)
Multiply both 276 and 159 by 037 and add the
products I would use the first method because
there are fewer steps and so fewer chances to
make errors
16 Sample answer You need to know how many
gallons of paint you need to paint a wall Measure
the length and width of the wall with a yardstick
then find the area Use the calculator to divide the
area by the number of square feet a gallon of the
paint covers Round up rather than down to the
nearest gallon so you have enough paint
MODULE 3
Ready to Go On
1 4 1 __ 5 =
5 times 4 + 1 _________
5 = 21 ___
5
42
5 ⟌ _
210
_ -20
1 0
_ -1 0
0
42
Copyright copy by Houghton Mifflin Harcourt 21 All rights reserved
2 12 14 ___ 15
= 15 times 12 + 14
___________ 15
= 194 ____ 15
129 _ 3
15 ⟌ _
194000
_ -15
44
_ -30
14 0
_ -13 5
50 first 50
_ -45
50 second 50
Because the number 50 repeats during the division
process the answer is a repeating decimal
129 _ 3 or 12933
3 5 5 ___ 32
= 32 times 5 + 5
__________ 32
= 165 ____ 32
515625
32 ⟌ _
16500000
_ -160
5 0
_ -3 2
1 80
_ -1 60
200
_ -192
80
_ -64
160
_ -160
0
515625
4 45 + 71 = 116
5 5 1 __ 6 + ( -3 5 __
6 ) = 4
6+1 ____
6 -3 5 __
6
= 1 2 __ 6
= 1 1 __ 3
6 - 1 __ 8 -6 7 __
8 = - 1 __
8 + ( -6 7 __
8 )
= -6 8 __ 8
= -7
7 142 - ( -49 ) = 142 + 49
= 191
8 -4 ( 7 ___ 10
) = - 4 __ 1 times 7 ___
10
= - 24 times 7 _______ 1 times 105
= - 2 times 7 _____ 1 times 5
= - 14 ___ 5 or -2 4 __
5
9 -32 ( -56 ) ( 4 ) = 32 times 56 times 4
= 7168
10 - 19 ___ 2 divide 38 ___
7 = -
119 times 7 _______ 2 times 382
= - 1 times 7 _____ 2 times 2
= - 7 __ 4
11 -3201 _______ -33
= 3201 _____ 33
97
33 ⟌ _
3201
_ -297
23 1
_ -23 1
0
97
12 Add the initial stock price with the increase from the
second day
$8360 + $1535 = $9895
Convert the percent decrease to a decimal
-4 3 __ 4 = -475 or -00475
Multiply the price on the second day times the
percent decrease and then subtract the result from
the price on the second day to find the final stock
price
$9895 times -00475 asymp -$47
$9895 - $47 = $9425
The final stock price is $9425 Yes this is
reasonable price on day 1 asymp $85 price on day
2 asymp $100 So the price on day 3 asymp $95
13 Sample answer You can use negative numbers to
represent temperatures below zero or decreases in
prices
Copyright copy by Houghton Mifflin Harcourt 22 All rights reserved
MODULE 4 Ratios and Proportionality
Are You Ready
1 3 __ 4 divide 4 __
5 = 3 __
4 times 5 __
4
= 15 ___ 16
2 5 __ 9 divide 10 ___
11 = 5 __
9 times 11 ___
10
= 1
5 __ 9 times 11 ___
10 2
= 11 ___ 18
3 3 __ 8 divide 1 __
2 = 3 __
8 times 2 __
1
= 4
3 __ 8 times 2 __
1 1
= 3 __ 4
4 16 ___ 21
divide 8 __ 9 = 16 ___
21 times 9 __
8
=thinsp 2
7 16 ___ 21
times 9 __ 8 3
1
= 6 __ 7
5 B ( -4 1 )
6 C ( 3 0 )
7 D ( 5 4 )
8 E ( -2 -2 )
9 F ( 0 0 )
10 G ( 0 -4 )
LESSON 41
Your Turn
3 1 __ 6 acre divide ( 1 __
4 hour ) = 1 __
6 times 4 __
1
= 3
1 times 4 _____ 6 times 1
2
= 1 times 2 _____ 3 times 1
= 2 __ 3 acre per hour
4 3 cups divide ( 3 __ 4 cups ) = 3 __
1 divide 3 __
4
= 3 __ 1 times 4 __
3
= 1
3 times 4 _____ 1 times 3
1
= 1 times 4 _____ 1 times 1
= 4 cups
5 Jaylan 3 __ 4 divide 1 __
5 = 3 __
4 times 5 __
1 = 15 ___
4 = 3 3 __
4
Wanchen 2 __ 3 divide 1 __
6 = 2 ___
1 3 times 6
2 __
1 = 4 __
1 = 4
Jaylanrsquos unit rate is 3 3 __ 4 cups of water per cup of lime
juice Wanchenrsquos unit rate is 4 cups of water per cup
of lime juice Wanchenrsquos limeade has a weaker lime
flavor because 4 gt 3 3 __ 4 and the limeade with a
greater ratio of water to lime juice will have a weaker
flavor
Guided Practice
1
Distance (mi) 8 1 __ 2 17 25 1 __
2 34 42 1 __
2
Time (h) 1 __ 2 1 1 1 __
2 2 2 1 __
2
2 3 1 __ 2 miles divide ( 1 1 __
4 hours ) = 7 __
2 divide 5 __
4 mi ___ h
= 7 times 4 _____ 2 times 5
= 1 7 times 4 _____ 2 times 5
2
= 7 times 2 _____ 1 times 5
= 14 ___ 5 mi ___
h
= 2 4 __ 5 miles per hour
3 5 __ 8 page divide ( 2 __
3 minute ) = 5 __
8 times 3 __
2
= 15 ___ 16
page per minute
4 1 __ 6 foot divide ( 1 __
3 hour ) = 1 __
6 times 3 __
1
= 2 1 times 3 _____ 6 times 1
1
= 1 times 1 _____ 2 times 1
= 1 __ 2 foot per hour
5 5 __ 8 sq ft divide ( 1 __
4 hour ) = 5 __
8 times 4 __
1
= 2 5 times 4 _____ 8 times 1
1
= 5 times 1 _____ 2 times 1
= 5 __ 2 or 2 1 __
2 square feet per hour
Solutions KeyRatios and Proportional Relationships
UNIT
2
Copyright copy by Houghton Mifflin Harcourt 23 All rights reserved
6 240 milligrams divide ( 1 __ 3 pickle ) = 240 ____
1 divide 1 __
3
= 240 ____ 1 times 3 __
1
= 720 ____ 1
Brand Arsquos rate is 720 mg per pickle
325 milligrams divide ( 1 __ 2 pickle ) = 325 ____
1 divide 1 __
2
= 325 ____ 1 times 2 __
1
= 650 ____ 1
Brand Brsquos rate is 650 milligrams per pickle and is
therefore lower than Brand A
7 The unit rate for Ingredient C is
1 __ 4 cup divide ( 2 __
3 serving ) = 1 __
4 times 3 __
2
= 3 __ 8
cup _______
serving
The unit rate for Ingredient D is
1 __ 3 cup divide ( 3 __
4 serving ) = 1 __
3 times 4 __
3
= 4 __ 9
cup _______
serving
To compare 3 __ 8 to 4 __
9 find the least common
denominator of 8 and 9 so that 3 __ 8 = 27 ___
72 and 4 __
9 = 32 ___
72
Therefore ingredient Crsquos unit rate is lower
8 Divide the number in the numerator by the number
in the denominator Write the result with the units of
the rate
For example 1 mile ______
1 __ 2 hour
= 1 __
1 __ 2 = 2 miles per hour
Independent Practice
9 a The unit rate in dollars per hour for On Call is
$10 divide ( 35 hours ) = 10 ___ 35
$ __
h asymp $286 per hour
The unit rate in dollars per hour for Talk Time is
$125 divide ( 1 __ 2 hours ) = 125 ____
05 $ __
h asymp $250 per hour
b Talk Time offers the better deal because its rate in
dollars per hour is lower
c To convert dollars per minute to dollars per hour
multiply by 60
$005 divide ( 1 minute )
= 005 ____ 1
$ ____
min times 60 min ______
1 h
= $3 per hour
d $3 per hour is more expensive than either On Call
or Talk Time so it is not a better deal than either
one
10 a Sample answer 1 __ 2 cup dried fruit to 1 __
8 cup
sunflower seeds in a granola recipe
b The ratio would not change if the recipe were
tripled because both numbers in the ratio would
be multiplied by the same number and therefore
the ratio would still be equivalent to what it was
originally
c 1 __ 2 divide 1 __
8 = 1 ___
1 2 times 8
4 __
1 = 4 __
1 = 4
Sample answer 4 cups dried fruit per 1 cup
sunflower seeds
11 10 songs
____________ 2 commercials
= 5 songs ____________
1 commercials
12 a Terrancersquos rate
6 mi divide ( 1 __ 2 h ) = 6 __
1 times 2 __
1
= 12 miles per hour
Jessersquos rate
2 mi divide ( 15 min ) = 2 __ 1 divide 1 __
4
= 2 __ 1 times 4 __
1 mi ___ h
= 8 miles per hour
b Terrance
50 mi divide ( 12 mi ___ h ) = 50 ___
1 times 1 ___
12
= 50 ___ 12
h
= 4 1 __ 6 h
= 4 10 ___ 60
h
= 4 hours and 10 minutes
Jesse
50 mi divide ( 8 mi ___ h ) = 50 ___
1 times 1 __
8
= 50 ___ 8 h
= 6 1 __ 4 h
= 6 15 ___ 60
h
= 6 hours and 15 minutes
c 8 mi divide ( 45 min ) = 8 __ 1 divide 3 __
4
= 8 __ 1 times 4 __
3
= 32 ___ 3
= 10 2 __ 3 miles per hour
Sandrarsquos unit rate is greater than Jessersquos but
lower than Terrancersquos so she runs slower than
Terrance but faster than Jesse
13 1 ___ 10
h = 6 ___ 60
h = 6 min
300 words _________ 6 min
= 50 words per min
1 ___ 12
h = 5 ___ 60
h = 5 min
300 words _________ 5 min
= 60 words per min
Faster Eli typed 50 words per minute in his first test
and 60 words per minute in his second test
Copyright copy by Houghton Mifflin Harcourt 24 All rights reserved
Focus on Higher Order Thinking
14 a For the 10-pack of 21 ounce bars
$1537 divide 10 bars asymp $154 per bar
For the 12-pack of 14 ounce bars
$1535 divide 12 bars asymp $128 per bar
The 12-pack has the better price per bar
b For the 10-pack
$1537 divide ( 10 times 21 oz ) = 1537 divide 21
asymp $073 per ounce
For the 12-pack
$1535 divide ( 12 times 14 oz ) = 1535 divide 168
asymp $091 per ounce
The 10-pack has a better price per ounce
c Sample answer Since I always eat them one bar
at a time the 12-pack is the better choice
15 Yes Half a room in half a day corresponds to a unit
rate of 1 __ 2 room divide ( 1 __
2 day ) = 1 room _____
day so at the same
rate the painter could paint 7 rooms in 7 days
16 Sample answer Take the reciprocal of the rate For
example a rate of 7 gallons per hour is equal to
1 hour per 7 gallons
LESSON 42
Your Turn
3 No the rates are not equal and therefore her speed
was not constant
4 Since the ratio of students to adults is constant the
relationship between them is proportional
students ________ adults
= 12 ___ 1 = 36 ___
3 = 60 ___
5 = 12 students per adult
If s = the number of students and a = the number
of adults then a = 1 ___ 12
s or s = 12a
Guided Practice
1 45 ___ 1 = 45 90 ___
2 = 45 135 ____
3 = 45 180 ____
4 = 45
The relationship is proportional
2 k = y __ x = 10 ___
2 = 5 y = 5x
3 k = y __ x = 2 __
8 = 1 __
4 y = 1 __
4 x
4 With the equation y = kx where k is the constant
of proportionality
Independent Practice
5 k = y __ x = 74 ___
4 = 1850 y = 1850x
6 $1099
_______ 05 days
= $2198 per day
7 Rent-All because it has the lowest price per day
($1850)
8 100 ft _____ 08 s
= 1000 _____ 8 ft __ s = 125 ft __ s
500 ft _____ 31 s
= 5000 _____ 31
ft __ s asymp 1613 ft __ s
1875 ft ______ 15 s
= 1875 ______ 15
ft __ s asymp 125 ft __ s
No Emtiaz assumed the relationship is proportional
but it is not The rate of change is not constant and
so his answer is not reasonable
9 $3125
______ 5 h
= $625 per hour and $5000
______ 8 h
= $625 per
hour Because the two unit rates are the same the
relationship between charge and time is proportional
10 The constant rate of change in this context means
that Steven charges $625 per hour
11 y = $625x where x is the number of hours Steven
babysits and y is the amount Steven charges
12 y = $625 ( 3 ) = $1875
13 300 ft _____ 2 min
= 6750
_____ 45
= 150 feet per minute
150 ft _____ min
times 60 min ______ 1 h
= 9000 feet per hour
14 y = 150x
15 Sample answer Feet per minute A submarine may
stay submerged for hours but it would not dive for
hours
Focus on Higher Order Thinking
16 Yes because there is a proportional relationship
so the distance and the time would increase by the
same factor
17 Sample answer Yes Even though the rates in the
table are not constant per ear of corn due to
rounding there is a constant rate for every 3 ears
of corn
LESSON 43
Your Turn
1 No because 11 ___ 1 ne 16 ___
2 Also the line drawn through
the points does not go through the origin
5 a The point ( 4 60 ) represents that the bicyclist can
ride a distance 60 miles in 4 hours
b k = 60 mi _____ 4 h
= 15 mi ___ h
c y = 15x where x is time in hours and y is
distance in miles
Guided Practice
1
Time (h) 3 5 9 10
Pages 195 325 585 650
Proportional the rate is a constant 65 pages
per hour
2
Time (h) 2 3 5 8
Earnings 15 2250 3750 60
Proportional the rate of is a constant $750 per hour
Copyright copy by Houghton Mifflin Harcourt 25 All rights reserved
3 Not proportional the relationship is linear but a line
drawn connecting the points will not pass through
the origin of ( 0 0 )
4 Proportional a line can be drawn that passes
through the points and also the origin of ( 0 0 )
5 k = 28 ft ____ 8 s
= 7 __ 2 ft __ s = 35 ft __ s y = 7 __
2 x or y = 35x where
x = time in seconds and y = height in feet
6 k = $2 ______
8 items = 1 __
4
$ _____
items = 025
$ _____
items so y = 1 __
4 x or
y = 025x where x = number of items and
y = cost in dollars
7 The graph is a straight line passing through the
origin
Independent Practice
8 It is the distance ( 0 miles ) that each horse runs in
0 minutes
9 Horse A runs 1 mile in 4 minutes
Horse B runs 1 mile in 25 minutes
10 For Horse A y = 1 __ 4 x
For Horse B y = 1 ___ 25
x or 2 __ 5 x
11 If x is time in minutes and y is distance in miles in
12 minutes Horse A will run 3 miles or 1 __ 4 ( 12 ) = 3
and Horse B will run 48 miles or 2 __ 5 ( 12 ) = 24 ___
5 = 48
12 Students may draw any straight line with a slope
steeper than 2 __ 5 that starts at the origin of ( 0 0 ) An
example is given below
2
2
4
6
8
10
4 6 8 10Time (min)
Dis
tanc
e (m
i)
A
B
O
13 Yes if the train is traveling at a constant speed the
ratio of miles traveled to time in hours will be
constant and therefore a graph comparing miles to
hours will form a straight line that passes through
the origin of ( 0 0 )
14 Sample answer When comparing relationships that
may be easier to observe on a graph than in an
equation
15 a
2
8
16
24
32
40
4 6 8 10DVDs
Cost
($)
O
b Sample answer The graph will pass through the
point ( 4 20 ) This point shows that four DVDs will
cost $20
16 The graph passes through the point ( 4 8 ) so
Glenda swam 8 feet in 4 seconds
17 Yes The graph is linear and passes through the
origin and therefore the rate of distance to time is
proportional at each point on the line
18 k = 8 ft ___ 4 s
= 2 ft __ s so y = 2x where x is time in
seconds and y is distance swam in feet It would
take 22 minutes to swim 1 __ 2 mile at this rate
Focus on Higher Order Thinking
19 Divide the second coordinate by the first to find the
constant of proportionality k Substitute the value of
k into the equation y = kx Then choose a value for x
and solve for y to find the ordered pair
20 Car 3 is not traveling at a constant speed
because 65 ___ 1 ne 85 ___
2
21 Since Car 4 is traveling at twice the speed it will
travel twice the distance as Car 2 in the same
amount of time Therefore the values in Car 4rsquos
distance column will be twice that shown in Car 2rsquos
distance column
MODULE 4
Ready to Go On
1 $140
_____ 18 ft 2
= $778 per square foot
2 $299
_____ 14 lb
asymp $021 per pound
3 $56 ______
25 gal = $224 per gallon
$3205
______ 15 gal
asymp $214 per gallon this is the better deal
4 $160
_____ 5 g
= $3200 per gram this is the better deal
$315
_____ 9 g
asymp $3500 per gram
5 No The ratio of dollars earned to lawns mowed is
not constant 15 ___ 1 ne 48 ___
3
Copyright copy by Houghton Mifflin Harcourt 26 All rights reserved
6 k = $9
___ 8euro
= $27 ____
24euro = 9 __
8 $ __
euro or 1125
$ __
euro So y = 9 __
8 x or
y = 1125x where x equals the number of euros
and y equals their value in dollars
7 The graph passes through the point ( 2 5 )
so k = 5 __ 2 servings
_______ pt
or k = 25 servings
_______ pt
Therefore
y = 5 __ 2
x or y = 25x where x equals the number
of pints and y equals the number of servings
8 The new graph will pass through the points ( 0 0 ) and ( 3 2 )
2
2
4
6
8
10
4 6 8 10Pints
Serv
ings
Frozen Yogurt
O
Therefore y = 2 __ 3 x where x equals the number of
pints and y equals the number of servings
9 Sample answer Compare corresponding values of
the variables to determine whether there is a
constant rate
Copyright copy by Houghton Mifflin Harcourt 27 All rights reserved
MODULE 5 Proportions and Percent
Are You Ready
1 22 = 22 ____ 100
= 022
2 75 = 75 ____ 100
= 075
3 6 = 6 ____ 100
= 006
4 189 = 100 + 89
= 100 ____ 100
+ 89 ____ 100
= 1 + 089
= 189
5 059 = 59
6 098 = 98
7 002 = 2
8 133 = 133
9 64
_ timesthinsp05
320
32
10 30
_ timesthinsp007
210
21
11 160
_ timesthinsp015
800
_ +1600
2400
24
12 62
_ timesthinsp032
124
_ +thinsp1860
1984
1984
13 4
_ timesthinsp12
8
_ +thinsp40
48
48
14 1000
_ timesthinsp006
6000
60
LESSON 51
Your Turn
2 x = ( $64 - 52 )
__________ $52
x = $12
____ $52
asymp 23
4 x = ( 18 - 12 )
________ 18
x = 6 ___ 18
asymp 33
5 x = ( 16 - 10 )
________ 16
x = 6 ___ 16
= 375
8 010 times $499 = $4990
$499 + $4990 = $54890
9 030 times $499 = $14970
$499 - $14970 = $34930
Guided Practice
1 x = ( $8 - $5 )
_________ $5
x = $3
___ $5
= 60
2 x = ( 30 - 20 )
_________ 20
x = 10 ___ 20
= 50
3 x = ( 150 - 86 )
__________ 86
x = 64 ___ 86
asymp 74
4 x = ( $389 - $349 )
______________ $349
x = $040
_____ $349
asymp 11
5 x = ( 14 - 13 )
________ 13
x = 1 ___ 13
asymp 8
6 x = ( 16 - 5 )
________ 5
x = 11 ___ 5 = 220
7 x = ( 64 - 36 )
_________ 36
x = 28 ___ 36
asymp 78
8 x = ( 80 - 64 )
_________ 80
x = 16 ___ 80
= 20
9 x = ( 95 - 68 )
_________ 95
x = 27 ___ 95
asymp 28
Copyright copy by Houghton Mifflin Harcourt 28 All rights reserved
10 x=( 90-45)_________
90
x=45___90
=50
11 x=( 145-132)__________
145
x=13____145
asymp9
12 x=( 64-21)_________
64
x=43___64
asymp67
13 x=( 16-0)________
16
x=16___16
=100
14 x=( 3-1__
2)_______
3
x=21__
2___
3 asymp83
15 010times$900=$090 $900+$090=$990
16 025times48=12 48-12=36cookies
17 020times340=68 $340-68=272pages
18 050times28=14 28+14=42members
19 004times$29000=$1160 $29000-$1160=$27840
20 130times810=1053 810+1053=1863songs
21 030times20=6 20+6=26miles
22 Dividetheamountofchangeinthequantitybytheoriginalamountthenexpresstheanswerasapercent
Independent Practice23
ItemOriginal
PriceNew Price
Percent Change
Increase or
DecreaseBike $110 $96 asympthinsp13 Decrease
Scooter $45 $56 asympthinsp24 Increase
TennisRacket $79 $8295 5 Increase
Skis $580 $435 25 Decrease
24 a 55
x=( 8-3)_______
8 =5__
8=625
x=( 12-7)________
12 =5___
12asymp417
Theamountofchangeisthesamebutthepercentofchangeislessfrom2010to2011
b Changewasgreatestbetween2009and2010
x=( 12-3)________
3
x=9__3=300increase
25 a Amountofchange=( 5-4)=1
Percentdecrease=1__5=20
b $100_____5 =$020each$100_____
4 =$025each
Amountofchange=$025-$020=$005
Percentincrease=$005_____$020
=25
26 Percenterror=( 136-133)___________
136 times100
=03____136
times100asymp2
Focus on Higher Order Thinking
27 a Theyhavethesame$100+$10=$110and$100+10( $100)=$110
b SylviahasmoreLeroihas$110+$10=$120andSylviahas$110+10( $110)=$121
c BecauseSylviawillhavemoreafterthesecondadditionaldepositandshewillbedepositingincreasingamountsshewillalwayshavemoreinheraccount
28 Thefinalamountisalways0becausea100decreaseofanyamountwouldbe0
29 NoOnlythefirstwithdrawalis$10Eachwithdrawalafterthatislessthan$10becauseitis10oftheremainingbalanceTherewillbemoneyleftafter10withdrawals
LESSON 52
Your Turn
2 a 1c+01c11c
b s=11times$28=$3080
3 a 200
b 1c+2c3c
5 a
1b - 024b
1b024b
b 1b-024b=076b
6 a 1p-005p095p
b 095p=$1425
CopyrightcopybyHoughtonMifflinHarcourt 29 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U2M05indd 29 103113 214 AM
Guided Practice
1 a 035s
b 1s + 035s 135s
c 135 times $3200 = $4320
d 035 times $3200 = $1120
Item Price Markup MarkupRetail
Price
2 Hat $18 15 $270 $2070
3 Book $2250 42 $945 $3195
4 Shirt $3375 75 $2531 $5906
5 Shoes $7499 33 $2475 $9974
6 Clock $4860 100 $4860 $9720
7 Painting $18500 125 $23125 $41625
8 $4500 - 022 ( $4500 ) = $3510
9 $8900 - 033 ( $8900 ) = $5963
10 $2399 - 044 ( $2399 ) = $1343
11 $27999 - 075 ( $27999 ) = $7000
12 Write the percent of markdown as a decimal
subtract the product of this decimal and the regular
price from the regular price
Independent Practice
13 a 046b
b 1b - 046b 054b
c 054 times $2900 = $1566
d 046 times $2900 = $1334
14 Regular Price $329
Sale Price $201
Regular Price $419
Sale Price $245
Regular Price $279
Sale Price $115
Regular Price $309
Sale Price $272
Regular Price $377
Sale Price $224
15 a Sample answer original price $100 final price
$050
b Sample answer original price $100 final price
$9950
c Sample answer original price $100 final price
$350
16 p = 127 ( $7400 ) = $9398
s = 127 ( $4800 ) = $6096
j = 127 ( $32500 ) = $41275
2 ( 9398 ) + 3 ( $6096 ) + $41275 = $78359
17 Either buy 3 get one free or 1 __ 4 off Either case would
result in a discount of 25 which is better than 20
Focus on Higher Order Thinking
18 No she is taking a loss Her cost for the tea is t so
the retail price is 12t The discounted price is
08 ( 12t ) or 096t which is less than t
19 No first change 201 decrease second change
251 increase The second percent change is
greater
20 Rafael can purchase the coat after 11 or 12 weeks
after 11 weeks the price is $10932 after 12 weeks
the price is $10385 and after that Danielle donates
the coat
LESSON 53
Your Turn
1 005 times $2000 = $100 $100 + $2000 = $2100
3 005 times $40000 = $2000
$2000 times 4 years = $8000
$40000 + $8000 = $48000
4 Commission $4500 times 00375 = $16875
Total $2200 + $16875 = $236875
Guided Practice
1 005 times $3000 = $150
2 015 times $7000 = $1050
3 0004 times $10000 = $040
4 15 times $2200 = $3300
5 001 times $8000 = $080
6 20 times $500 = $1000
7 a 007 times $4399 = $308
b $4399 + $308 = $4707
8 115 times $7550 = $8683
9 007 times $2000 = $140
$140 times 5 years = $700
10 003 times $550 = $1650
$1650 times 10 years = $165
$550 + $165 = $715
11 a 090 times $20 = $18
b 1085 times $18 = $1953
12 020 times $2999 = $600 tip
00625 times $2999 = $187 tax
$2999 + $600 + $187 = $3786 total
13 Write the tax rate as a decimal Then multiply the
decimal by the price of the item and add the result
to the price
Independent Practice
14 $3275 + $3988 = $7263 total meal cost
014 times $7263 = $1017 tip
$7263 + $1017 = $8280 total with tip
15 $7865 times 015 = $1180 meal discount
$7865 times 020 = $1573 tip
$7865 + $1573 - $1180 = $8258 total
16 $125 times 235 = $29375 retail ring cost
0075 times $29375 = $2203 tax
$29375 + $2203 = $31578 total with tax
Copyright copy by Houghton Mifflin Harcourt 30 All rights reserved
17 $7999 times 012 = $960 discount
$7999 - $960 = $7039 price before tax
$7039 times 10675 = $7514 total with tax
18 4 times $999 times 020 = $799 discount
4 times $999 - $799 = $3197 price before tax
$3197 times 10675 = $3413 total with tax
19 $4500 + 00725 = $32625 commission
$750 + $32625 = $107625 total income
20 $700 times 0055 = $3850 commission
$475 + $3850 = $51350 total income
21 a Multiply Sandrarsquos height by 010 and add the
product to 4 to get Pablorsquos height Then multiply
Pablorsquos height by 008 and add the product to
Pablorsquos height to get Michaelarsquos height
b Using 48 inches for 4 feet
48 inches times 01 = 48 inches so Pablorsquos height is
53 inches or 4 feet 5 inches to the nearest inch
53 inches times 008 = 42 inches so Michaelarsquos
height is 57 inches or 4 feet 9 inches to the
nearest inch
22 a $4998 times 05 = $2499 50 discount
$2499 - $1000 = $1499 $10 discount
b $4998 - $1000 = $3998 $10 discount
$3998 times 05 = $1999 50 discount
23 a $95 times 09 = $8550 discounted camera
$8550 + $1599 = $10149 total
b $1599 times 09 = $1439 discounted battery
$95 + $1439 = $10939 total
c Eric should apply the discount to the digital
camera he can save $8
d $10149 times 008 = $812 tax
$10149 + $812 = $10961 total
24 a Store 1 $22 divide 2 = $11
Store 2 $1299 times 09 = $1169
Store 1 charges $11 per shirt and Store 2
charges $1169 Therefore I would save
$069 per shirt at Store 1
b Store 3 $2098 times 045 = $944
Yes It is selling shirts at $944
Focus on Higher Order Thinking
25 Marcus should choose the option that pays $2400
plus 3 of sales He would make $2550 to $2700
per month The other option would pay only $1775
to $2050 per month
26 Percent error = ǀ 132 - 137 ǀ
____________ 137
times 100 = 05 ____ 137
asymp 36
MODULE 5
Ready to Go On
1 x = ( 63 - 36 )
_________ 36
x = 27 ___ 36
= 75 increase
2 x = ( 50 - 35 )
_________ 50
x = 15 ___ 50
= 30 decrease
3 x = ( 72 - 40 )
_________ 40
x = 32 ___ 40
= 80 increase
4 x = ( 92 - 69 )
_________ 92
x = 23 ___ 92
= 25 decrease
5 $60 times 015 = $9
$60 + $9 = $69
6 $32 times 0125 = $4
$32 + $4 = $36
7 $50 times 022 = $11
$50 - $11 = $39
8 $125 times 030 = $3750
$12500 - $3750 = $8750
9 $4800 times 0065 = $312 commission
$325 + $312 = $637 total income
10 $5310
______ $1735
asymp 31
11 Find the amount per hour that Priya makes if she
makes 20 more than James
$700 times 020 = $140
$700 + $140 = $840
Next find the amount Slobhan makes if he makes
5 less than Priya
$840 times 005 = $042
$840 - $042 = $798
Slobhan makes $798 per hour
12 Both the 6 tax and the 20 tip are applied to the
initial cost of the meal so the two percents can be
added together and multiplied by the cost
$45 times 026 = $1170
$45 + $1170 = $5670
The total cost of the meal is $5670
13 Sample answer sales tax increase discount
decrease tip increase
Copyright copy by Houghton Mifflin Harcourt 31 All rights reserved
MODULE 6 Expressions and Equations
Are You Ready
1 5 + x
2 11 - n
3 -9 ___ y
4 2x - 13
5 2x + 3
= 2 ( 3 ) + 3
= 6 + 3
= 9
6 -4x + 7
= -4 ( 1 ) + 7
= -4 + 7
= 11
7 15x - 25
= 15 ( 3 ) - 25
= 45 - 25
= 2
8 04x + 61
= 04 ( -5 ) + 61
= -20 + 61
= 41
9 2 __ 3 x - 12
= 2 __ 3
( 18 ) - 12
= 2 __ 3
times ( 18 ___ 1 ) - 12
= 36 ___ 3 - 12
= 0
10 - 5 __ 8
x + 10
= - 5 __ 8 ( -8 ) + 10
= - 5 __ 8 times- 8 __
1 + 10
= - 5 ___ 1 8
times- 8 1 __
1 + 10
= - 5 __ 1 times- 1 __
1 + 10
= 5 + 10
= 15
11 1 __ 2 divide 1 __
4
= 1 times 4 _____ 2 times 1
= 1 times 4 2 ______
1 2 times 1
= 1 times 2 _____ 1 times 1
= 2
12 3 __ 8 divide 13 ___
16
= 3 __ 8 times 16 ___
13
= 3 times 16 2 _______
1 8 times 13
= 3 times 2 ______ 1 times 13
= 6 ___ 13
13 2 __ 5 divide 14 ___
15
= 2 __ 5 times 15 ___
14
= 1 2 times 15
3 ________
1 5 times 14 7
= 1 times 3 _____ 1 times 7
= 3 __ 7
14 4 __ 9 divide 16 ___
27
= 4 __ 9 times 27 ___
16
= 1 4 times 27
3 ________
1 9 times 16 4
= 1 times 3 _____ 1 times 4
= 3 __ 4
LESSON 61
Your Turn
2 ( 3x + 1 __ 2 ) + ( 7x - 4 1 __
2 )
= 3x + 7x + 1 __ 2 - 4 1 __
2
= 10x - 4
3 ( -025x - 3 ) - ( 15x + 14 ) = -025x - 3 - 15x - 14
= -175x - 44
4 02(3b - 15c) + 6c
= 06b - 3c + 6c
= 06b + 3c
5 2 __ 3 (6e + 9f - 21g) - 7f
= 4e + 6f - 14g - 7f
= 4e - f - 14g
6 5x - 3(x - 2) - x
= 5x - 3x + 6 - x
= x + 6
7 83 + 34y - 05(12y - 7)
= 83 + 34y - 6y + 35
= 118 - 26y
Solutions KeyExpressions Equations and Inequalities
UNIT
3
Copyright copy by Houghton Mifflin Harcourt 32 All rights reserved
Guided Practice
1 baseballs 14 + (12)n tennis balls 23 + (16)n
14 + 12n + 23 + 16n
14 + 23 + 12n + 16n
37 + 28n
So the total number of baseballs and tennis balls is
37 + 28n
2 37 + 28n
37 + 28 ( 9 )
= 37 + 252
= 289
3 14 + 5(x + 3) - 7x = 14 + 5x + 15 - 7x
= 29 - 2x
4 3 ( t - 4 ) - 8 ( 2 - 3t ) = 3t - 12 - 16 + 24t
= 27t - 28
5 63c - 2 ( 15c + 41 ) = 63c - 3c - 82
= 33c - 82
6 9 + 1 __ 2 ( 7n - 26 ) - 8n = 9 + 35n - 13 - 8n
= -4 - 4 1 __ 2 n
7 2x + 12
2 ( x + 6 )
8 12x + 24
12 ( x + 2 )
9 7x + 35
7 ( x + 5 )
10 You multiply numbers or expressions to produce a
product You factor a product into the numbers or
expressions that were multiplied to produce it
Independent Practice
11 Let d = number of days
Fee for 15 food booths 15 ( 100 + 5d ) Fee for 20 game booths fee 20 ( 50 + 7d ) Amount the company is paid for the booths
15 ( 100 + 5d ) + 20 ( 50 + 7d ) = 15 ( 100 ) + 15 ( 5d ) + 20 ( 50 ) + 20 ( 7d )
= 1500 + 75d + 1000 + 140d
= 1500 + 1000 + 75d + 140d
= 2500 + 215d
12 New length 96 + l
New width 60 + w
Perimeter of new pattern
2(96 + l) + 2(60 + w)
=2(96) + 2l + 2(60) + 2w
192 + 2l + 120 + 2w
192 + 120 + 2l + 2w
312 + 2l + 2w
13 Width 3
Length 1 x-tile and 2 +1-tiles
Factors 3 and x + 2
Product 3 ( x + 2 ) = 3x + 6
14 Width 4
Length 2 x-tiles and 1 -1-tile
Factors 4 and 2x - 1
Product 4 ( 2x - 1 ) = 8x - 4
15 The area is the product of the length and width
( 6 times 9 ) It is also the sum of the areas of the
rectangles separated by the dashed line ( 6 times 5
and 6 times 4 ) So 6 ( 9 ) = 6 ( 5 ) + 6 ( 4 )
16 Perimeter of triangle ( x + 3 ) + ( 2x + 4 ) +
6x = ( x + 3 ) + ( 2x + 4 ) +
6x = 3x + 7 +
-3x = _ -3x
3x = 7 +
_ -7 = _ -7
3x - 7 =
The length of the side is 3x - 7
17 Perimeter of rectangle 2 ( 3x - 3 ) + 2 ( )
10x + 6 = 2 ( 3x - 3 ) + 2 ( )
10x + 6 = 6x - 6 + 2
_ -6x = _ -6x
4x + 6 = - 6 + 2
_ + 6 = _ + 6
4x + 12 = 2
( 4x + 12 ) divide 2 = ( 2 ) divide 2
2x + 6 =
The length of the side is 2x + 6
18 a P = 2l + 2w
Perimeter of tennis court T
2(2x + 6) + 2(x)
= 4x + 12 + 2x
= 6x + 12
Perimeter of basketball court B
2(3x - 14) + 2( 1 __ 2 x + 32)
= 6x - 28 + x + 64
= 7x + 36
b (7x + 36) - (6x + 12)
= 7x + 36 - 6x - 12
= x + 24
c Find the length of tennis court
Let x = 36
2x + 6 = 2 ( 36 ) + 6
= 72 + 6
= 78
Find the width of the basketball court
Let x = 36
1 __ 2 x + 32 = 1 __
2 ( 36 ) + 32
= 18 + 32
= 50
Find the length of the basketball court
Let x = 36
3x - 14 = 3 ( 36 ) - 14
= 108 - 14
= 94
The tennis court is 36 ft by 78 ft The basketball
court is 50 ft by 94 ft
Focus on Higher Order Thinking
19 Find the area of each small square and rectangle
( x ) ( x ) = x 2
( x ) 1 = x
( 1 ) 1 = 1
Copyright copy by Houghton Mifflin Harcourt 33 All rights reserved
x
x
1
11
1 1
x2 x x x
x 1 1 1x 1 1 1
Area =
x 2 + x + x + x + x + x + 1 + 1 + 1 + 1 + 1 + 1
= x 2 + 5x + 6
( x + 3 ) ( x + 2 ) = x 2 + 5x + 6
20 Agree To find 58 times 23 let 23 = 3 + 20 Then find
the product 58 ( 3 + 20 ) First step 58 ( 3 ) = 174
Second step 58 ( 20 ) = 1160 Third step 174 +
1160 = 1334 So 58 ( 23 ) = 58 ( 3 ) + 58 ( 20 )
21 ( 1 ) Think of 997 as 1000 - 3 So 8 times 997 = 8 ( 1000 - 3 ) By the Distributive Property
8 ( 1000 - 3 ) = 8000 - 24 = 7976
( 2 ) Think of 997 as 900 + 90 + 7 By the Distributive
Property 8 ( 900 + 90 + 7 ) = 7200 + 720 + 56 =
7976
LESSON 62
Your Turn
1 49 + z = -9
_ -49 _ -49
z = -139
2 r - 171 = -48
_ +171 _ +171
r = 123
3 -3c = 36
-3c ____ -3
= 36 ___ -3
c = -12
5 x - 15 = 525
_ +15 _ +15
x = 675
The initial elevation of the plane is 675 miles
6 x ___ 35
= -12
x ___ 35
( 35 ) = -12 ( 35 )
x = -42
The decrease in the value of the stock was $420
7 25x = 75
25x ____ 25
= 75 ___ 25
x = 3
The power was restored in 3 hours
Guided Practice
1 Let x represent the number of degrees warmer the
average temperature is in Nov than in Jan
x + ( -134 ) = -17 or x - 134 = -17
x - 134 = -17
_ +134 _ +134
x = 117
The average temperature in November is 117degF
warmer
2 Let x represent the number of days it takes the
average temperature to decrease by 9degF
-1 1 __ 2 x = -9
( - 2 __ 3 ) ( - 3 __
2 x ) = ( - 2 __
3 ) ( -9 )
x = 18 ___ 3
x = 6
It took 6 days for the temperature to decrease by 9degF
3 -2x = 34
-2x ____ -2
= 34 ___ -2
x = -17
4 y - 35 = -21
_ + 35 _ + 35
y = 14
y = 14
5 2 __ 3 z = -6
( 3 __ 2 ) 2z ___
3 = ( 3 __
2 ) ( -6 )
z = -9
6 Sample answer It helps me describe the problem
precisely and solve it using inverse operations
Independent Practice
7 Let x equal the elevation of Mt Everest
x - 870737 = 203215
_ +870737 _ +870 737
x = 2902887
The elevation of Mt Everest is 2902887 ft
8 Let x equal the number of feet Liam descended
2825131 - x = 2320106
_ -2825131 _ -2825131
-x = - 505025
x = 505025
Liam descended 505025 ft
His change in elevation was -505025 ft
9 Let x equal the elevation of Mt Kenya
2825131 - x = 1119421
_ -2825131 _ -2825131
-x = -1705710
x = 1705710
The elevation of Mt Kenya is 170571 ft
10 Find the change in elevation
1250 - 935 = 315
Use an equation
Let x = the number of minutes the balloon
descends
( -22 1 __ 2 ) x = -315
( - 45 ___ 2 ) x = -315
( - 2 ___ 45
) ( - 45 ___ 2 ) x = -315 ( - 2 ___
45 )
x = 14
It will take the balloon 14 minutes to descend
11 Find the change in elevation
4106 - 3205 = 901
Use an equation to find the rate of descent
Copyright copy by Houghton Mifflin Harcourt 34 All rights reserved
Let x = rate of descent
34x = 901
34x ____ 34
= 901 ____ 34
x = 265 = 26 1 __ 2
The rate of descent was 26 1 __ 2 feet per minute
12 Let x = the number of degrees warmer Montanarsquos
average temperature is than Minnesotarsquos
- 25 + x = -07
_ + 25 _ + 25
x = 18
Montanarsquos average 3-month temperature is 18degC
warmer than Minnesotarsquos
13 Let x = the number of degrees warmer Floridarsquos
average temperature is than Montanarsquos
181 - x = -07
_ - 181 _ -181
-x = -188
x = 188
Floridarsquos average 3-month temperature is 188degC
warmer than Montanarsquos
14 Let x = the number of degrees the average
temperature in Texas would have to change
125 + x = 181
_ -125 _ -125
x = 56
It would have to increase by 56degC
15 Let x = the number of yards the team must get on
their next play
-26 1 __ 3
+ x = 10
+26 1 __ 3
______
+26 1 __ 3
______
x = 36 1 __ 3
The team needs to get 36 1 __ 3 yards on their next play
16 Let x = the number of seconds
( -2 1 __ 2 ) x = -156
( -25 ) x = -156
( -25 _____ -25
) x = -156 ______ -25
x = 624
It takes the diver 624 seconds to reach -156 feet
17 Sample answer The elevation is the product of the
rate and the time
18 Let x = the total amount withdrawn
x __ 5 = 455
( 5 ) x __ 5 = 455 ( 5 )
x = 2275
The total amount she withdrew was $22750
Sample answer
$4550 asymp $50 and $50 times 5 = $250 which is close
to $22750
Focus on Higher Order Thinking
19 ( 1 ) The elevations of the diver and the reef both are
below sea level
( 2 ) The change in the planersquos elevation the plane
descends the plane is moving from a higher to a
lower elevation
20 -4x = -48
( -4x ____ -4
) = -48 _____ -4
x = 12
- 1 __ 4 x = -48
( -4 ) ( - 1 __ 4 ) x = -48 ( -4 )
x = 192
192 ____ 12
= 16
In the first case -4x = -48 you divide both sides
by -4 In the second - 1 __ 4 x = -48 you multiply
both sides by -4 The second solution (192) is
16 times the first (12)
21 Add the deposits and the withdrawals Let x repre-
sent the amount of the initial deposit Write and
solve the equation x + deposits - withdrawals =
$21085
LESSON 63
Your Turn
4 Let x represent the number of video games Billy
purchased
Original balance on gift card $150
Cost for x video games $35 middot x
Final balance on gift card $45
Original balance minus $35 times number of games equals $45
darr darr darr darr darr darr darr $150 - $35 middot x = $45
Equation 150 - 35x = 45
5 Sample answer You order x pounds of coffee from
Guatemala at $10 per pound and it costs $40 to
ship the order How many pounds can you order so
that the total cost is $100
Guided Practice
1
+ + ++ ++
+++ + +
+++
2
----
+ ++ ++
- - -
Copyright copy by Houghton Mifflin Harcourt 35 All rights reserved
3 Let a represent the number of adults that attend
Ticket cost for 1 child = $6
Ticket cost for a adults = $9 middot a
Total cost for movie = $78
cost for child plus $9 times number of adults equals $78
darr darr darr darr darr darr darr $6 + $9 middot a = $78
Equation 6 + 9a = 78
4 x is the solution of the problem
2x is the quantity you are looking for multiplied by 2
+ 10 means 10 is added to 2x
= 16 means the result is 16
5 Sample answer A department store is having a sale
on recliners buy two and get a discount of $125
Sanjay purchases two recliners and the total cost
(before taxes) is $400 What is the price of a single
recliner not including any discounts
6 Choose a variable to represent what you want to
find Decide how the items of information in the
problem relate to the variable and to each other
Then write an equation tying this all together
Independent Practice
7 On one side of a line place three negative variable
tiles and seven +1-tiles and then on the other side
place 28 +1-tiles
8 Let d represent the number of days Val rented the
bicycle
Flat rental fee $5500
Cost for d days of rental $850 middot dTotal cost $123
$850 times number of days plus flat fee equals total cost
darr darr darr darr darr darr darr $850 bull d + $55 = $123
Equation 85d + 55 = 123
9 Let r represent the number of refills
Refill mug cost $675
Cost for r refills $125 middot r Total cost $3175
$125 times number of refills plus refill mug cost equals total cost
darr darr darr darr darr darr darr $125 bull r + $675 = $3175
Equation 125r + 675 = 3175
10 Let n represent the number of weekday classes
The Saturday class lasts 60 minutes
The length of time for the weekday classes is 45 middot n
The total number of minutes for all classes in a week
is 28545 minutes times number of plus minutes for equals total minutes
weekday classes Saturday class
darr darr darr darr darr darr darr45 bull n + 60 = 285
Equation 45n + 60 = 285
11 Let n represent the number of African animals
Half the number of African animals is 1 __ 2 n
45 more than the number of African animals
means + 45
The total number of animals is 172
half times number of and 45 more than number equals total number
African animals of African animals of animals
darr darr darr darr darr darr
1 _ 2
bull n + 45 = 172
Equation 1 __ 2 n + 45 = 172
12 Let u represent the number of uniforms
Cost for basketball equipment $548
Cost for u uniforms $2950 middot uTotal cost $2023
$2950 times number of plus cost for basketball equals total cost
uniforms equipment
darr darr darr darr darr darr darr $2950 bull u + $548 = $2023
Equation 295u + 548 = 2023
13 Let x represent the number of weeks
Initial amount in account $500
$20 per week 20 middot xFinal amount in account $220
initial amount minus 20 times number of equals final amount
weeks
darr darr darr darr darr darr darr 500 - 20 bull x = 220
Equation 500 - 20x = 220
14 a The equation adds 25 but Deenarsquos scenario
involves subtracting 25
b Let x represent the number of shirts
Cost of shirts before discount 9 middot xDiscount means subtract
Amount of discount $25
Total bill $88
9 times number of minus discount equals total
shirts bill
darr darr darr darr darr darr darr 9 bull x - 25 = 88
Equation 9x - 25 = 88
c Sample answer I bought some shirts at the store
for $9 each and a pair of jeans for $25 making
my bill a total of $88 How many shirts did I buy
15 a Let c represent the number of children
Flat fee for Sandy $10
Cost per child for Sandy $5 middot cTotal charge for Sandy $10 + $5c
Total charge for Kimmi $25
To compare the two costs set these values equal
Equation 10 + 5c = 25
b Solve the equation to find c the number of
children a family must have for Sandy and Kimmi
to charge the same amount
10 + 5c = 25
10 - 10 + 5c = 25 - 10
5c = 15
5c ___ 5 = 15 ___
5
c = 3
3 children
c They should choose Kimmi because she charges
only $25 If they chose Sandy they would pay
10 + 5 ( 5 ) = $35
Copyright copy by Houghton Mifflin Harcourt 36 All rights reserved
Focus on Higher Order Thinking
16 To get Andresrsquo equation you can multiply every
number in Peterrsquos equation by 4 To get Peterrsquos
equation you can divide every number in Andrewrsquos
equation by 4 or multiply by 1 __ 4
17 Part of the equation is written in cents and part in
dollars All of the numbers in the equation should be
written either in cents or dollars
18 Sample answer Cici has a gift card with a balance
of 60 She buys several T-shirts for $8 each Her new
balance is $28 after the purchases Write an
equation to help find out how many T-shirts Cici
bought
LESSON 64
Your Turn
1 Model the equation
+ ++ +
+ ++ ++ +
+ ++ ++ +
++
Remove 5 +1-tiles from each side of the mat
+ ++ +
+ ++ ++ +
+ ++ ++ +
++
Divide each side into two equal groups
++
+ ++ +
++
The solution is x = 3
++ ++
2 Model the equation
+ + ++ + ++ +
+++
+++
__
Add 1 +1-tile to each side of the mat Note that
a negative-positive tile pair results in zero
+ + ++ + ++
++ +
+++
+++
__
Divide each side into two equal groups
+ + ++++ + +++
The solution is n = 3
+ + +++
3 Model the equation
++++
______
______
____
Add 3 +1-tiles to each side of the mat Note that
a negative-positive tile pair results in zero
++++
+
++
+
++
______
______
____
Divide each side into two equal groups
++++
____
The solution is a = -1
++ __
Copyright copy by Houghton Mifflin Harcourt 37 All rights reserved
4 Model the equation
____
________
++
Add 2 -1-tiles to each side of the mat Note that
a negative-positive tile pair results in zero
________
________
++
____
Divide each side into two equal groups
________
________
We get -y = -1
____
In order to change -y to y add a positive y-variable
tile to each side
++
__ ++ __
Add 1 +1-tile to each side of the mat
++++
__
The solution is y = 1
+++
6 3n + 10 = 37
Solve the equation for n
3n + 10 = 37
-10 ____
-10 ____
3n = 27
3n ___ 3 = 27 ___
3
n = 9
The triplets are 9 years old
7 n __ 4 - 5 = 15
Solve the equation for n
n __ 4 - 5 = 15
+5 ___
+5 ___
n __ 4 = 20
n __ 4 ( 4 ) = 20 ( 4 )
n = 80
The number is 80
8 -20 = 5 __ 9 ( x - 32 )
Solve the equation for x
-20 = 5 __ 9 ( x - 32 )
-20 = 5 __ 9 x - 160 ____
9
+ 160 ____ 9
______
+ 160 ____ 9
______
- 20 ___ 9 = 5 __
9 x
- 20 ___ 9 divide ( 5 __
9 ) = 5 __
9 x divide ( 5 __
9 )
4 20 times 9
1 _______
9 1 times 5
1 = x
- 4 __ 1 = x
-4 = x
The temperature in the freezer is -4degF
9 120 - 4x = 92
Solve the equation for x
120 - 4x = 92
-120 _____
-120 _____
- 4x = -28
-4x ____ -4
= -28 ____ -4
x = 7
She had 7 incorrect answers
Copyright copy by Houghton Mifflin Harcourt 38 All rights reserved
Guided Practice
1 To solve the equation with algebra tiles first remove
one +1-tile from both sides Then divide each side
into two equal groups
2 Remove 1 +1-tile from each side
++++
+ +++++++++
Divide each side into two equal groups
++++
++++++++
The solution is x = 4
++ + + + +
3 Let w = the width of the frame
2 times height plus 2 times width equals perimeter
darr darr darr darr darr darr darr darr darr2 bull 18 + 2 bull w = 58
Solve the equation
2 ( 18 ) + 2w = 58
36 + 2w = 58
36 - 36 + 2w = 58 - 36
2w = 22
2w ___ 2 = 22 ___
2
w = 11
The width is 11 inches
4 1200 minus 25x = 500
Solve the equation for x
1200 - 25x = 500
_ -1200 _ -1200
-25x = -700
-25x _____ -25
= -700 _____ -25
x = 28
The manager will reorder in 28 days
5 Use the inverse operations of the operations
indicated in the problem If the equation does
not involve parentheses use addition or subtraction
before multiplication or division to solve the
equation
Independent Practice
6 9s + 3 = 57
9s + 3 - 3 = 57 - 3
9s = 54
9s ___ 9 = 54 ___
9
s = 6
7 4d + 6 = 42
4d + 6 - 6 = 42 - 6
4d = 36
4d ___ 4 = 36 ___
4
d = 9
8 115 - 3y = -485
115 - 115 - 3y = -485 - 115
thinsp-3y = -60
-3y
____ -3
= -60 ____ -3
y = 20
9 k __ 2 + 9 = 30
k __ 2 + 9 - 9 = 30 - 9
k __ 2 = 21
2 sdot k __ 2 = 2 sdot 21
k = 42
10 g
__ 3 - 7 = 15
g
__ 3 - 7 + 7 = 15 + 7
g
__ 3 = 22
3 sdot g
__ 3 = 3 sdot 22
g = 66
11 z __ 5 + 3 = -35
z __ 5 + 3 - 3 = -35 - 3
z __ 5 = -38
5 sdot z __ 5 = 5 ( -38 )
z = -190
12 -9h - 15 = 93
-9h - 15 + 15 = 93 + 15
-9h = 108
-9h ____ -9 = 108 ____
-9
h = -12
13 - 1 __ 3 (n + 15) = -2
- 1 __ 3 n - 5 = -2
- 1 __ 3 n - 5 + 5 = -2 + 5
- 1 __ 3 n = 3
-3 sdot - 1 __ 3 n = -3 sdot 3
n = -9
14 -17 + b __ 8 = 13
-17 + 17 + b __ 8 = 13 + 17
b __ 8 = 30
8 sdot b __ 8 = 8 sdot 30
b = 240
Copyright copy by Houghton Mifflin Harcourt 39 All rights reserved
15 7 ( c - 12 ) = -21
7c - 84 = -21
_ +84 _ +84
7c = 63
7c ___ 7 = 63 ___
7
c = 9
16 -35 + p
__ 7 = -52
-35 + 35 + p
__ 7 = -52 + 35
p
__ 7 = -17
7 sdot p
__ 7 = -17 sdot 7
p = -119
17 46 = -6t - 8
46 + 8 = -6t - 8 + 8
54 = -6t
54 ___ -6
= -6t ____ -6
t = -9
18 Let a = the original amount in the account
Double the (original plus 26) equals new
sum of amount amount
darr darr darr darr darr darr
2 (a + $26) = $264
Solve the equation
2 ( a + 26 ) = 264
2 ( a + 26 )
_________ 2 = 264 ____
2
a + 26 = 132
a + 26 - 26 = 132 - 26
a = 106
Puja originally had $106 in the account
19 Let t = the temperature 6 hours ago
Twice temperature less 6 degrees equals current
6 hours ago temperature
darr darr darr darr darr darr 2middot t - 6 = 20
Solve the equation
2t - 6 = 20
2t - 6 + 6 = 20 + 6
2t = 26
2t __ 2 = 26 ___
2
t = 13
Six hours ago it was 13 degF in Smalltown
20 -35 = 5 __ 9 ( x - 32 )
-35 = 5 __ 9 x - 160 ____
9
+ 160 ____ 9
______
+ 160 ____ 9
- 155 ____ 9 = 5 __
9 x
thinsp- 155 ____ 9 divide ( 5 __
9 ) = 5 __
9 x divide ( 5 __
9 )
-thinsp 31
155 times 9
1
= x
9 1
times 5
1
- 31 ___ 1 = x
-31 = x
The temperature is -31degF
21 Let a = Artaudrsquos ageopposite of Artaudrsquos age add 40 equals 28
darr darr darr darr darr darr(-) a + 40 = 28
Solve the equation
-a + 40 = 28
-a + 40 - 40 = 28 - 40
-a = -12
-a ___ -1
= -12 ____ -1
a = 12
Artaud is 12 years old
22 Let c = number of customers when Sven startedtwice number of
customers when Sven started
plus 11 more equals present number of customers
darr darr darr darr darr2 middot c +11 = 73
Solve the equation
2c + 11 = 73
2c + 11 - 11 = 73 - 11
2c = 62
2c ___ 2 = 62 ___
2
c = 31
Sven had 31 customers when he started
23 Let p = original price of the jacket
half original less $6 equals amount
price paid
darr darr darr darr darr
1 __ 2
middot p -6 = 88
Solve the equation
1 __ 2 p - 6 = 88
1 __ 2 p - 6 + 6 = 88 + 6
1 __ 2 p = 94
2 sdot 1 __ 2 p = 2 sdot 94
p = 188
The original price was $188
Copyright copy by Houghton Mifflin Harcourt 40 All rights reserved
24 115 minus 8n = 19
Solve the equation for n
115 - 8n = 19
_ -115 _ -115
-8n = -96
-8n _____ -8
= -96 _____ -8
n = 12
They had 19 apples left after 12 days
25 -55x + 056 = -164
-55x + 056 - 056 = -164 - 056
-55x = -22
-55x ______ -22
= -22 _____ -22
x = 04
26 -42x + 315 = -651
-42x + 315 - 315 = -651 - 315
-42x = -966
-42x ______ -42
= -966 ______ -42
x = 23
27 k ___ 52
+ 819 = 472
k ___ 52
+ 819 - 819 = 472 - 819
k ___ 52
= -347
52 sdot k ___ 52
= 52 ( -347 )
k = -18044
28 Sample answer -3x - 5 = -26
29 Sample answer x __ 5 + 10 = 5
30 When dividing both sides by 3 the student forgot to
divide 2 by 3
3x + 2 = 15
3x ___ 3 + 2 __
3 = 15 ___
3
x + 2 __ 3 = 5
- 2 __ 3
___
- 2 __ 3
___
x = 5 - 2 __ 3
x = 5 times3
___ 1
times3 - 2 __
3
x = 15 ___ 3 - 2 __
3
x = 13 ___ 3 or 4 1 __
3
The solution should be x = 4 1 __ 3
31 a 2(x + 40) = 234
Solve the equation for x
2x + 80 = 234
2x + 80 - 80 = 234 - 80
2x = 154
2x ___ 2 = 154 ____
2
x = 77
Trey saved $77
b Sample answer In both solutions you would
divide $234 by 2 then subtract 40 234 divide 2 ndash 40
= 77 These are the same operations applied in
the same order as when solving the equation
Focus on Higher Order Thinking
32 F = 18c + 32
F - 32 = 18c + 32 - 32
F - 32 = 18c
F - 32 ______ 18
= 18c ____ 18
F - 32 ______ 18
= c
33 P = 2 ( ℓ + w ) P = 2ℓ + 2w
P - 2ℓ = 2ℓ - 2ℓ + 2w
P - 2ℓ = 2w
P - 2ℓ ______ 2 = 2w ___
2
P - 2ℓ ______ 2 = w
34 ax + b = c
ax + b - b = c - b
ax = c - b
ax ___ a = c - b ______ a
x = c - b ______ a
MODULE 6
Ready to Go On
1 Add the amounts for the cost of first day of the field
trip with the second day of the field trip where n is
the number of members in the club
15n + 60 + 12n + 95
Therefore the total cost of the two-day field trip can
be written as the expression 27n + 155
2 h + 97 = -97
_ -97 _ -97
h = -194
3 - 3 __ 4 + p = 1 __
2
+ 3 __ 4 + 3 __
4
p = 1 __ 2 + 3 __
4
p = 1 times2
___ 2
times2 + 3 __
4
p = 2 __ 4 + 3 __
4
p = 5 __ 4
4 -15 = -02k
-15 _____ -02
= -02k ______ -02
75 = k
Copyright copy by Houghton Mifflin Harcourt 41 All rights reserved
5 y ___
-3 = 1 __
6
y ___
-3 ( -3 ) = 1 __
6 ( -3 )
y = 1 __ 6 times -3 ___
1
y = -3 ___ 6
y = -1 ___ 2
6 - 2 __ 3
m = -12
- 2 __
3 m _____
- 2 __ 3 = -12 ____
- 2 __ 3
m = -12 divide - 2 __ 3
m = -12 ____ 1 divide - 2 __
3
m = -12 ____ 1 times - 3 __
2
m = -36 ____ -2
m = 18
7 24 = - t ___ 45
24 ( 45 ) = - t ___ 45
( 45 )
108 = -t
-108 = t
8 Let d represent the number of the day after the first
day for example d = 1 means the first day after the
day he started number of number number
2 times day after plus of sit-ups equals of sit-ups
first day first day today
darr darr darr darr darr darr darr
2 middot d + 15 = 33
Equation 2d + 15 = 33
9 5n + 8 = 43
5n + 8 - 8 = 43 - 8
5n = 35
5n ___ 5 = 35 ___
5
n = 7
10 y __
6 - 7 = 4
y __
6 - 7 + 7 = 4 + 7
y __
6 = 11
6 sdot y __
6 = 6 sdot 11
y = 66
11 8w - 15 = 57
8w - 15 + 15 = 57 + 15
8w = 72
8w ___ 8 = 72 ___
8
w = 9
12 g
__ 3 + 11 = 25
g
__ 3 + 11 - 11 = 25 - 11
g
__ 3 = 14
3 sdot g
__ 3 = 3 sdot 14
g = 42
13 f __ 5 - 22 = -25
f __ 5 - 22 + 22 = -25 + 22
f __ 5 = -03
5 sdot f __ 5 = 5 ( -03 )
f = -15
14 - 1 __ 4 (p + 16) = 2
- 1 __ 4 p - 4 = 2
- 1 __ 4 p - 4 + 4 = 2 + 4
- 1 __ 4 p = 6
-4 sdot - 1 __ 4 p = 6 sdot -4
p = -24
15 Sample answer Analyze the situation to determine
how to model it using a two-step equation Solve
the equation Interpret the solution in the given
situation
Copyright copy by Houghton Mifflin Harcourt 42 All rights reserved
MODULE 7 Inequalities
Are You Ready
1 9w = -54
9w ___ 9 = -54 ____
9
w = -6
2 b - 12 = 3
thinsp _ + 12 = _ + 12
b = 15
3 n __ 4
= -11
4 times n __ 4
= 4 ( -11 )
n = -44
4-7
ndash5ndash10 0 5 10
75 4 6
8 3 - (-5)
3 + 5
8
9 -4 - 5
-9
10 6 - 10
-4
11 -5 - (-3)
-5 + 3
-2
12 8 - (-8)
8 + 8
16
13 9 - 5
4
14 -3 - 9
-12
15 0 - (-6)
0 + 6
6
LESSON 71
Your Turn
4 y minus 5 ge minus7
_ +5 _ +5
y ge minus2
-4-5 -3 -2-1 0 1 2 3 4 5
Check Substitute 0 for y
minus1 ge -8
minus1(minus2) le -8(minus2)
2 le 16
5 21 gt 12 + x
_ -12 _ minus12
9 gt x
x lt 9
10 2 3 4 5 6 7 8 9 10
Check Substitute 8 for x
21 gt 12 + 8
21 gt 12 + 8
21 gt 20
6 -10y lt 60
-10y
_____ -10
lt 60 ____ -10
y gt -6
-10-9 -8 -7 -6 -5 -4 -3 -2-1 0 1
Check Substitute -5 for y
-10y lt 60
-10(-5) lt 60
50 lt 60
7 7 ge - t __ 6
7(-6) le - t __ 6 (-6)
-42 le t
t ge -42
-46 -45 -44 -43 -42 -41 -40-47
Check Substitute -36 for t
7 ge - t __ 6
7 ge - ( -36 ____
6 )
7 ge 6
8 Write and solve an inequality
Let m = the number of months
35m le 315
35m ____ 35
le 315 ____ 35
m le 9
Tony can pay for no more than 9 months of his gym
membership using this account
Guided Practice
1 -5 le -2
_ +7 _ +7
2 le 5
2 -6 lt -3
-6 ___ -3
gt -3 ___ -3
2 gt 1
3 7 gt -4
_ -7 _ -7
0 gtthinsp -11
Copyright copy by Houghton Mifflin Harcourt 43 All rights reserved
4 -1 ge -8
-1 ( -2 ) le -8 ( -2 )
2 le 16
5 n - 5 ge -2
_ +5 _ +5
n ge 3
-5 -4 -3 -2-1 0 3 4 51 2
Check Substitute 4 for n
n - 5 ge -2
4 - 5 ge -2
-1 ge -2
6 3 + x lt 7
_ -3 _ -3
x lt 4
-2-1 0 3 4 5 6 7 81 2
Check Substitute 3 for x
3 + x lt 7
3 + 3 lt 7
6 lt 7
7 -7y le 14
-7y
____ -7 ge 14 ___ -7
y ge -2
-5-6-7 -4 -3 -2-1 0 1 2 3
Check Substitute -1 for y
-7y le 14
-7 ( -1 ) le 14
7 le 14
8 b __ 5 gt -1
b __ 5 ( 5 ) gt -1 ( 5 )
b gt -5
-5-6-7-8 -4 -3 -2-1 0 1 2
Check Substitute 0 for b
b __ 5 gt -1
0 __ 5 gt
-1
0 gt -1
9 a -4t ge -80
b -4t ge -80
-4t ____ -4
le -80 ____ -4
t le 20
It will take the physicist 20 or fewer hours to change
the temperature of the metal
c The physicist would have to cool the metal for
more than 20 hours for the temperature of the
metal get cooler than -80deg C
10 You reverse the inequality symbol when you divide
or multiply both sides of an inequality by a negative
number
Independent Practice
11 x - 35 gt 15
_ + 35 _ +35
x gt 50
100 20 30 40 50 60 70 80 90100
Check Substitute 51 for x
x - 35 gt 15
51 minus 35 gt 15
16 gt 15
12 193 + y ge 201
_ -193 _ minus193
y ge 8
10 2 3 4 5 6 7 8 9 10
Check Substitute 9 for y
193 + y ge 201
193 + 9 ge 201
202 ge 201
13 - q
__ 7 ge -1
- q
__ 7 ( -7 ) le -1 ( -7 )
q le 7
8 9 105 6 70 1 2 3 4
Check Substitute ndash14 for q
- q
__ 7 ge -1
- -14 ____ 7 ge
-1
2 ge -1
14 -12x lt 60
-12x _____ -12
gt 60 ____ -12
x gt -5
0-10-9 -8 -7 -6 -5 -4 -3 -2-1
Check Substitute -4 for x
-12x lt 60
-12 ( -4 ) lt 60
48 lt 60
15 5 gt z -3
_ +3 _ +3
8 gt z
z lt 8
10 2 3 4 5 6 7 8 9 10
Check Substitute 7 for z
5 gt z - 3
5 gt 7 - 3
5 gt 4
Copyright copy by Houghton Mifflin Harcourt 44 All rights reserved
16 05 le y __
8
05 ( 8 ) le y __
8 ( 8 )
4 le y
y ge 4
8 9 105 6 70 1 2 3 4
Check Substitute 8 for y
05 le y __
8
05 le 8 __
8
05 le 1
17 Write and solve an inequality
Let x = the number of inches
12 + x le 28
_ -12 _ -12
x le 16
The puppy will grow at most 16 inches more
18 Write and solve an inequality
Let w = the total weight of the kittens
w __ 7 lt 35
w __ 7 ( 7 ) lt 35 ( 7 )
w lt 245
The possible combined weights of the kittens is any
weight less than 245 ounces but greater than 0
19 Write and solve an inequality
Let s = the number of sides
6s le 42
6s ___ 6 le 42 ___
6
s le 7
The length of a side is at most 7 inches
20 Write and solve an inequality
Let x = the amount Tom needs to spend
3025 + x ge 50
_ -3025 _ -3025
x ge 1975
Tom needs to spend at least $1975
21 Write and solve an inequality
Let w = the width of the region
155w ge 1705
155w ______ 155
ge 1705 _____ 155
w ge 11
The possible width of the region is at least 11 feet
22 Write and solve an inequality
Let t = the number of seconds
thinsp-12t lt -120
-12t _____ -12
gt -120 _____ -12
t gt 10
No let t be the number of seconds the descent
takes the inequality is ndash12t lt -120 so t gt 10 so
the submarinersquos descent takes 10 seconds or more
23 Write and solve an inequality
Let s = the amount of spinach
3s le 10
3s ___ 3 le 10 ___
3
s le 3 1 __ 3
The greatest amount of spinach she can buy is 3 1 __ 3
pounds
24 Write and solve an inequality
Let m = the amount of money Gary has
m ___ 05
le 55
m ___ 05
( 05 ) le 55 ( 05 )
m le 275
Gary has at most $275
25 Write and solve an inequality
Let x = the number of pounds of onions
125x le 3
125x _____ 125
le 3 ____ 125
x le 24
No 125x le 3 x le 24 so 24 pounds of onions is
the most Florence can buy 24 lt 25 so she cannot
buy 25 pounds
Focus on Higher Order Thinking
26 If you divide both sides of -7z ge 0 by -7 and do
not reverse the inequality symbol you get z ge 0
This is incorrect because if you choose a value from
the possible solutions such as z = 1 and substitute
it into the original equation you get -7 ge 0 which is
not true
27 x gt 9 for each inequality in each case the number
added to x is 9 less than the number on the right
side of each inequality so x gt 9 is the solution
28 Find the formula for the volume of a rectangular
prism
V = lwh
Write and solve an inequality
Let h = the height in inches
( 13 ) ( 1 __ 2 ) h lt 65
65h lt 65
65h ____ 65
lt 65 ___ 65
h lt 10
All heights greater than 0 in and less than 10 in
( 13 ) ( 1 __ 2 ) h lt 65 65h lt 65 h lt 10 A height cannot
be 0 or less than 0 so h gt 0 and h lt 10
Copyright copy by Houghton Mifflin Harcourt 45 All rights reserved
LESSON 72Your Turn
3 Let a represent the amount each member must
raise
Number of members 45
Starting amount $1240
Target amount $6000
starting number amount each is greater target
amount plus of members times member than or amount
must raise equal to
darr darr darr darr darr darr darr $1240 + 45 middot a ge $6000
Equation 1240 + 45a ge 6000
4 Let n represent the greatest number of rides Ella
can go on
Starting amount $40
Admission price $6
Cost for each ride $3
admission cost for number is less starting
price plus each ride times of rides than or amount
equal to
darr darr darr darr darr darr darr $6 + $3 middot n le $40
Equation 6 + 3n le 40
5 x is the solution of the problem the quantity you
are looking for
3x means that for a reason given in the problem
the quantity you are looking for is multiplied by 3
+ 10 means that for a reason given in the problem
10 is added to 3x
gt 30 means that after multiplying the solution x by
3 and adding 10 to it the result must be greater
than 30
Sample answer An exam consists of one essay
question worth 10 points and several multiple choice
questions worth 3 points each If Petra earns full
points on the essay question how many multiple
choice questions must she get right in order to get
a score greater than 30 points
6 x is the solution of the problem the quantity you are
looking for
5x means that for a reason given in the problem
the quantity you are looking for is multiplied by 5
-50 means that for a reason given in the problem
50 is subtracted from 5x
le 100 means that after multiplying the solution x by
5 and subtracting 50 from it the result must be less
than or equal to 100
Sample answer Miho has $100 to spend on her
garden She spends $50 on gardening supplies
Vegetable plants cost $5 each What is the greatest
number of plants she can buy
Guided Practice
1
- -- -
-
lt
++++++
+ + ++ + +
+
2
---
gt
+ + ++ + +
+ + ++ + +
+ + +
3 Let a represent the amount each member must
raise
Amount to be raised $7000
Amount already raised $1250
Number of members 92 amount number of amount each is greater target
already plus members times member than or amount
raised raises equal to
darr darr darr darr darr darr darr 1250 + 92 times a ge 7000
The inequality that represents this situation is
1250 + 92a ge 7000
4 x is the solution of the problem 7x is the solution
multiplied by 7 -18 means that 18 is subtracted
from 7x le 32 means that the result can be no
greater than 32
5 Sample answer Alexa has $32 to spend on T-shirts
for her friends She has a gift card worth $18 T-shirts
cost $7 each How many T-shirts can Alexa buy
6 Sample answer Choose a variable to represent
what you want to find Decide how the information in
the problem is related to the variable Then write an
inequality
Independent Practice
7 number possible amount is
of times amount each minus for more $200
friends friend earns supplies than
darr darr darr darr darr darr darr 3 middot a - $28 gt $200
3a + 28 gt 200
Let a = possible amount each friend earned
8 cost of number cost of less than amount
bagel times of bagels plus cream or equal Nick
cheese to has
darr darr darr darr darr darr darr $075 middot n + $129 le $700
075n + 129 le 700
Let n = the number of bagels Nick can buy
9 number max amount amount less than total amount
of shirts times each shirt minus of gift or equal Chet can
can cost certificate to spend
darr darr darr darr darr darr darr 4 sdot a - 25 le 75
4a - 25 le 75Let a = the maximum amount each shirt can cost
Copyright copy by Houghton Mifflin Harcourt 46 All rights reserved
10 number of number number of is less total
seats in plus of rows on times seats in than equal number
balcony ground floor one row equal to of people
darr darr darr darr darr darr darr 120 + 32 middot n le 720
120 + 32n le 720
Let n = the number of people in each row
11 amount commission amount greater than earning
earned per plus rate times of sales or equal to for this
month month
darr darr darr darr darr darr darr 2100 + 005 middot s ge 2400
2100 + 005s ge 2400
Let s = the amount of her sales
12 number number average greater
of cans plus of days times number of than goal
collected cans per day
darr darr darr darr darr darr darr 668 + 7 n gt 2000
668 + 7n gt 2000
Let n = the average number of cans collected each
day
13 cost per cost per number of less than total amount
month plus CD times CDs she or equal spent in
buys to a month
darr darr darr darr darr darr darr
$7 + $10 middot c le $100
7 + 10c le 100
Let c = the number of CDs Joanna buys
14 cost of cost for number of less than total amount
belt plus each times shirts he or equal of money
shirt can buy to Lionel has
darr darr darr darr darr darr darr
$22 + $17 middot n le $80
22 + 17n le 80
Let n = the number of shirts he can buy
15 Sample answer Mr Craig is buying pizzas for the
7th grade field day He can spend up to $130 and
needs 15 pizzas He has a $20 coupon How much
can he spend per pizza $10 or less per pizza
16 ldquoat leastrdquo in this case means m ge 25
17 ldquono greater thanrdquo in this case means k le 9
18 ldquoless thanrdquo in this case means p lt 48
19 ldquono more thanrdquo in this case means b le -5
20 ldquoat mostrdquo in this case means h le 56
21 ldquono less thanrdquo in this case means w ge 0
22 The average score of the three tests Marie has
already taken and the three she will still take
is given by
95 + 86 + 89 + 3s
________________ 6
where s is the average score on the three remaining
tests
This value needs to be greater than or equal to 90
so the inequality can be written as
95 + 86 + 89 + 3s
________________ 6 ge 90 or
95 + 86 + 89 + 3s ge 540 or
270 + 3s ge 540
Focus on Higher Order Thinking
23 5 + 10 lt 20 Sample answer If the combined length
of two sides of a triangle is less than the length of
the third side the two shorter sides will not be long
enough to form a triangle with the third side Here
the combined length of 5 ft and 10 ft is 15 ft not
enough to make a triangle
24 -m gt 0 Sample answer Since m is less than 0 it
must be a negative number -m represents the
opposite of m which must be a positive number
since the opposite of a negative number is positive
So -m gt 0
25 n gt 1 __ n if n gt 1
n lt 1 __ n if n lt 1
n = 1 __ n if n = 1
LESSON 73
Your Turn
1 Model the inequality
++
++++
+++
++++
++++
+++
gt
Add seven -1-tiles to both sides of the mat
++
++++
+++
++++
++++
+++
gt
- -- -- --
- -- -- --
Remove zero pairs from both sides of the mat
++
++++
gt
Divide each side into equal groups
++
++++
gt
Copyright copy by Houghton Mifflin Harcourt 47 All rights reserved
The solution is x gt 2
+ + +gt
2 Model the inequality
+++++
----
+++++
+ +++++
ge
Add four +1-tiles to both sides of the mat
+++++
----
+++++
+ ++
++++
+++
++++
ge
Remove zero pairs from the left side of the mat
+++++
+++++
+ +++++
++++
ge
Divide each side into equal groups
+++++
+++++
+ +++++
++++
ge
The solution is h ge 3
+ + + +ge
3 Use inverse operations to solve the inequality
5 - p
__ 6 le 4
5 - 5 - p
__ 6 le 4 - 5
thinsp- p
__ 6 le -1
thinsp-6 ( - p
__ 6 ) ge -6 ( -1 )
p ge 6
Graph the inequality and interpret the circle and
arrow
0 1 4 5 72 3 6 8 9 10
Joshua has to run at a steady pace of at least 6 mih
4 Substitute each value for v in the inequality
3v - 8 gt 22
v = 9 v = 10 v = 11
3 ( 9 ) - 8 gt 22 3 ( 10 ) - 8 gt 22 3 ( 11 ) - 8 gt 22
Evaluate each expression to see if a true inequality
results
3 ( 9 ) - 8 gt 22 3 ( 10 ) - 8 gt
22 3 ( 11 ) - 8 gt
22
27 - 8 gt 22 30 - 8 gt
22 33 - 8 gt
22
19 gt 22 22 gt
22 25 gt
22
not true not true true
v = 11
5 Substitute each value for h in the inequality
5h + 12 le -3
h = -3 h = -4 h = -5
5 ( -3 ) + 12 le -3 5 ( -4 ) + 12 le -3 5 ( -5 ) + 12 le -3
Evaluate each expression to see if a true inequality
results
5 ( -3 ) + 12 le -3 5 ( -4 ) + 12 le
-3 5 ( -5 ) + 12 le
-3
-15 + 12 le -3 -20 + 12 le
-3 -25 + 12 le
-3
-3 le -3 -8 le
-3 -13 le
-3
true true true
h = -3 h = -4 h = -5
Copyright copy by Houghton Mifflin Harcourt 48 All rights reserved
Guided Practice
1 Remove 4 +1-tiles from both sides then divide each
side into 3 equal groups the result is x lt 3
2 Use inverse operations to solve the inequality
5d - 13 lt 32
5d - 13 + 13 lt 32 + 13
5d lt 45
5d ___ 5 lt 45 ___
5
d lt 9
Graph the inequality
20 6 84 10 12 14 16 18 20
3 Use inverse operations to solve the inequality
-4b + 9 le -7
-4b + 9 - 9 le -7 - 9
-4b le -16
-4b ____ -4
ge -16 ____ -4
b ge 4
Graph the inequality
20 6 84 10 12 14 16 18 20
4 Substitute each value for m in the inequality
2m + 18 gt - 4
m = -12 m = -11 m = -10
2 ( -12 ) + 18 gt -4 2 ( -11 ) + 18 gt -4 2 ( -10 ) + 18 gt -4
Evaluate each expression to see if a true inequality
results
2 ( -12 ) + 18 gt -4 2 ( -11 ) + 18 gt
- 4 2 ( -10 ) + 18 gt
- 4
- 24 + 18 gt -4 - 22 + 18 gt
- 4 - 20 + 18 gt
- 4
- 6 gt - 4 - 4 gt
- 4 - 2 gt
- 4
not true not true true
m = -10
5 Substitute each value for y in the inequality
- 6y + 3 ge 0
y = 1 y = 1 __ 2 y = 0
-6 ( 1 ) + 3 ge 0 -6 ( 1 __ 2 ) + 3 ge 0 -6 ( 0 ) + 3 ge 0
Evaluate each expression to see if a true inequality
results
-6 ( 1 ) + 3 ge 0 - 6 ( 1 __
2 ) + 3 ge
0 - 6 ( 0 ) + 3 ge
0
-6 + 3 ge 0 -3 + 3 ge
0 0 + 3 ge
0
-3 ge 0 0 ge
0 3 ge
0
not true true true
y = 1 __ 2
y = 0
6 Solve the inequality
65 - 4t ge 15
65 - 65 - 4t ge 15 - 65
-4t ge -5
-4t ____ -4
le -5 ___ -4
t le 125
Graph the inequality
0 05 1 15 2 25
Lizzy can spend from 0 to 125 h with each student
No 15 h per student will exceed Lizzyrsquos available
time
7 Sample answer Apply inverse operations until you
have isolated the variable If you multiply or divide
both sides of the inequality by a negative number
reverse the direction of the inequality symbol
Independent Practice
8 2s + 5 ge 49
2s + 5 - 5 ge 49 - 5
2s ge 44
2s ___ 2 ge 44 ___
2
s ge 22
10 14 1612 18 20 22 24 26 28 30
9 -3t + 9 ge -21
-3t + 9 - 9 ge -21 -9
-3t ge -30
-3t ____ -3
le -30 ____ -3
t le 10
ndash2ndash4ndash6ndash8ndash10 0 2 4 6 8 10
10 55 gt -7v + 6
55 - 6 gt -7v + 6 - 6
49 gt - 7v
49 ___ -7 lt -7v ____ -7
v gt -7
-10-9 -8 -7 -6 -5 -4 -3 -2 -1 0
11 21 1 __ 3 gt 3m - 2 2 __
3
21 1 __ 3 + 2 2 __
3 gt 3m - 2 2 __
3 + 2 2 __
3
24 gt 3m
24 ___ 3 gt 3m ___
3
8 gt m or m lt 8
0 1 4 5 72 3 6 8 9 10
12 a ___ -8
+ 15 gt 23
a ___ -8
+ 15 - 15 gt 23 - 15
a ___ -8
gt 8
-8 ( a ___ -8
) lt -8 ( 8 )
a lt -64
-70 -68 -66 -64 -62 -60
Copyright copy by Houghton Mifflin Harcourt 49 All rights reserved
13 f __ 2 - 22 lt 48
f __ 2 - 22 + 22 lt 48 + 22
f __ 2 lt 70
2 ( f __ 2 ) lt 2 ( 70 )
f lt 140
100 110 120 130 140 150
14 -25 + t __ 2 ge 50
-25 + 25 + t __ 2 ge 50 + 25
t __ 2 ge 75
2 ( t __ 2 ) ge 2 ( 75 )
t ge 150
130 140 150 160 170 180
15 10 + g ___
-9 gt 12
10 - 10 + g ___
-9 gt 12 - 10
g ___
-9 gt 2
-9 ( g ___
-9 ) lt -9 ( 2 )
g lt -18
-20 -18 -14 -12 -10-16
16 252 le -15y + 12
252 - 12 le -15y + 12 - 12
24 le - 15y
24 ____ -15
ge -15y
_____ -15
y le -16
-20 -18 -14 -12 -10-16
17 -36 ge -03a + 12
-36 - 12 ge -03a + 12 - 12
-48 ge -03a
-48 _____ -03
le -03a ______ -03
a ge 16
10 11 12 13 14 16 17 18 19 2015
18 80 - 2w ge 50
80 - 80 - 2w ge 50 - 80
- 2w ge -30
-2w ____ -2
le -30 ____ -2
w le 15
The width is a positive number no greater than
15 inches the possible widths in inches will be 10
11 12 13 14 and 15
19 Inequality 7n - 25 ge 65
7n - 25 ge 65
7n - 25 + 25 ge 65 + 25
7n ge 90
7n ___ 7 ge 90 ___
7
n ge 12 6 __ 7
Grace must wash at least 13 cars because n must
be a whole number
Focus on Higher Order Thinking
20 No Sample answer If x lt x - 1 then subtracting
x from both sides of the inequality 0 lt -1 That is
untrue so no value of x can be less than x - 1
21 a
10 3 42 5 6 7 8 9 10
b
10 3 42 5 6 7 8 9 10
c A number cannot simultaneously be less than 2
and greater than 7 Therefore there is no number
that satisfies both inequalities
d Consider the graph of x gt 2 and x lt 7
The solution includes all the numbers on the
number line so the solution set is all numbers
22 Sample answer Joseph might have reasoned that n
was first multiplied by 2 then increased by 5 to give
a result less than 13 Working backward he would
have subtracted 5 from 13 ( to get 8 ) then divided by
2 ( to get 4 ) giving n lt 4 Shawnee would have
followed these same steps but would have used a
variable and invers operations
MODULE 7
Ready to Go On
1 n + 7 lt -3
thinsp _ -7
_ -7
n lt -10
2 5p ge -30
5p
___ 5 ge -30 ____
5
p ge -6
3 14 lt k + 11
_ -11 _ -11
3 lt k
4 d ___ -3
le minus6
( -3 ) ( d ) ge ( -3 ) ( -6 )
d ge 18
Copyright copy by Houghton Mifflin Harcourt 50 All rights reserved
5 c - 25 le 25
_ +25 _ +25
c le 5
6 12 ge -3b
12 ___ -3
le -3b _____ -3
-4 le b
7 Let n be the number of minimum points Jose must
score 562 + n ge 650
Solve the inequality
562 + n ge 650
_ -562 _ -562
n ge 88
8 Let t be the number of minutes Lainey can descend
-20 - 20t ge -100
9 2s + 3 gt 15
_ -3 _ -3
2s gt 12
2s ___ 2
gt 12 ___ 2
s gt 6
10 - d ___ 12
- 6 lt 1
_ +6 _ +6
- d ___ 12
lt 7
12 ( - d ___ 12
) lt 12 ( 7 )
-d lt 84
d gt -84
11 -6w - 18 ge 36
_ +18 _ +18
thinsp-6w ge 54
-6w _____ -6
le 54 ___ -6
w le -9
12 z __ 4 + 22 le 38
_ -22 _ -22
z __ 4 le 16
4 ( z __ 4 ) le 4 ( 16 )
z le 64
13 b __ 9 - 34 lt -36
_ +34 _ +34
b __ 9 lt -2
9 ( b __ 9 ) lt 9 ( -2 )
b lt -18
14 -2p + 12 gt 8
-12 ____
-12 ____
-2p gt -4
-2p
____ -2 lt -4 ___
-2
p lt 2
15 Sample answer Look for key words or phrases
that indicate inequality such as ldquogreater thanrdquo
ldquoless thanrdquo ldquoat mostrdquo or ldquoat leastrdquo
Copyright copy by Houghton Mifflin Harcourt 51 All rights reserved
MODULE 8 Modeling Geometric Figures
Are You Ready
1 3x + 4 = 10
3x + 4 - 4 =10 - 4
3x = 6
3x ___ 3 = 6 __
3
x = 2
2 5x - 11 = 34
5x - 11 + 11 = 34 + 11
5x = 45
5x ___ 5 = 45 ___
5
x = 9
3 -2x + 5 = -9
-2x + 5 - 5 = -9 - 5
-2x = -14
-2x ____ -2
= -14 ____ -2
x = 7
4 -11 = 8x + 13
-11 - 13 = 8x + 13 - 13
-24 = 8x
-24 ____ 8 = 8x ___
8
-3 = x
5 4x - 7 = -27
4x - 7 + 7 = -27 + 7
4x = -20
4x ___ 4 = -20 ____
4
x = -5
6 1 __ 2 x + 16 = 39
1 __ 2 x + 16 - 16 = 39 - 16
1 __ 2 x = 23
( 2 ) 1 __ 2 x = ( 2 ) 23
x = 46
7 12 = 2x - 16
12 + 16 = 2x - 16 + 16
28 = 2x
28 ___ 2 = 2x ___
2
14 = x
8 5x - 15 = -65
5x - 15 + 15 = -65 + 15
5x = -50
5x ___ 5 = -50 ____
5
x = -10
9 x __ 5 = 18 ___
30
x times 30 = 5 times 18
30x = 90
30x ____ 30
= 90 ___ 30
x = 3
10 x ___ 12
= 24 ___ 36
x times 36 = 12 times 24
36x = 288
36x ____ 36
= 288 ____ 36
x = 8
11 3 __ 9 = x __
3
3 times 3 = 9 times x
9 = 9x
9 __ 9 = 9x ___
9
1 = x
12 14 ___ 15
= x ___ 75
14 times 75 = 15 times x
1050 = 15x
1050 _____ 15
= 15x ____ 15
70 = x
13 8 __ x = 14 ___ 7
8 times 7 = x times 14
56 = 14x
56 ___ 14
= 14x ____ 14
4 = x
14 14 ___ x = 2 __ 5
14 times 5 = x times 2
70 = 2x
70 ___ 2 = 2x ___
2
35 = x
15 5 __ 6 = x ___
15
5 times 15 = 6 times x
75 = 6x
75 ___ 6 = 6x ___
6
125 = x
Solutions KeyGeometry
UNIT
4
Copyright copy by Houghton Mifflin Harcourt 52 All rights reserved
16 81 ___ 33
= x ____ 55
81 times 55 = 33 times x
4455 = 33x
4455 _____ 33
= 33x ____ 33
135 = x
LESSON 81
Your Turn
6 Length 132 in times 5 ft ____ 3 in
= 22 ft
Width 6 in times 5 ft ____ 3 in
= 10 ft
Area 10 ft ( 22 ft ) = 220 square feet
Guided Practice
1
Blueprint
length (in)3 6 9 12 15 18
Actual
length (ft)5 10 15 20 25 30
a The wall is 30 feet long
b 25 ft times 3 in ____ 5 ft
= 15 in
2 The width is 7 in times 4 ft ____ 2 in
= 14 ft and the length is
14 in times 4 ft ____ 2 in
= 28 ft and the area is
28 ft ( 14 ft ) = 392 square feet
3 Length 10 cm times 5 m _____ 2 cm
= 25 m
Width 6 cm times 5 m _____ 2 cm
= 15 m
Area 25 m ( 15 m ) = 375 square meters
4 a
b Length is 36 m and width is 24 m using both
scales
5 If the scale drawing is complete and accurate you
can use it to find any length or area of the object of
the drawing
Independent Practice
6 a 2 in times 40 cm ______ 1 in
= 80 cm
15 in times 40 cm ______ 1 in
= 60 cm
The dimensions of the painting are 80 cm by 60 cm
b 80 cm times 60 cm = 4800 c m 2
c 80 cm times 1 in _______ 254 cm
asymp 315 in
60 cm times 1 in _______ 254 cm
asymp 236 in
The dimensions of the painting are approximately
315 in by 236 in
d 315 in times 236 in asymp 743 i n 2
7 120 ft times 1 unit _____ 5 ft
= 24 units
75 ft times 1 unit _____ 5 ft
= 15 units
The dimensions of the drawing are 24 units by
15 units
8 Sample answer 2 in6 ft 1 in3 ft and 1 in1 yd
9 Because the scale is 10 cm1 mm and because
10 cm is longer than 1 mm the drawing will be
larger
10 a Let r represent the scale
54 ft times r = 810 m
r = 810 m ______ 54 ft
r = 150 m ______ 1 ft
The scale is 1 ft = 150 m
b 54 ft times 12 in _____ 1 ft
= 648 in
Let b represent the number of tiny bricks
b = 648 in times 1 brick ______ 04 in
b = 162 bricks
The model is 162 tiny bricks tall
11 a Let h represent the height of the model
h = 30 ft times 126 cm _______ 1 ft
h = 378 cm
Let n represent the number of toothpicks
n = 378 cm times 1 toothpick
_________ 63 cm
n = 6 toothpicks
The model will be 6 toothpicks tall
b 378 cm times 1 swab ______ 76 cm
asymp 5 swabs
The model will be about 5 cotton swabs tall
Focus on Higher Order Thinking
12 If the area of the scale drawing is 100 square cm
then one side is 10 cm Let s represent the side
length of the actual floor
s = 10 cm times 2 ft _____ 1 cm
s = 20 ft
So the area is 20 ft(20 ft) = 400 ft 2
The ratio of areas is 100 square cm 400 square feet
or 1 square cm 4 square feet
Copyright copy by Houghton Mifflin Harcourt 53 All rights reserved
13 Decide on the new scale yoursquod like to use Then find
the ratio between the old scale and the new scale
and redraw the scale drawing accordingly For
example the ratio could be 13 In that case you
would redraw the dimensions at three times the
original size
14 Sample answer 1 __ 4 in 8 ft 40 ft by 24 feet 960 f t
2
LESSON 82
Guided Practice
1 The two angles 45deg and a right angle or 90deg with
the included side 8 cm determine the point at which
the sides meet so a unique triangle is formed
2 The sum of the measures of the two short sides
4 + 3 = 7 The sum is less than the measure of the
long side 11 so no triangle is formed
3 The two angles 40deg and 30deg with the included side
7 cm determine the point at which the sides meet
so a unique triangle is formed
4 The sum of the measures of the two short sides
6 + 7 = 13 The sum is greater than the measure of
the long side 12 so a unique triangle is formed
5 Sample answer Segments with lengths of 5 in
5 in and 100 in could not be used to form a
triangle
Independent Practice
6 A figure with side lengths of 3 centimeters and 6
centimeters and an included angle of 120deg deter-
mine the length of the third side of a triangle and so
produce a unique triangle
6 cm
3 cm120˚
7 The side lengths proposed are 15 ft 21 ft and 37 ft
The sum of the measures of the two shorter sides
15 + 21 = 36 So the sum is less than the measure
of the long side 37 No such triangle can be created
8 The three angle measures can be used to form
more than one triangle The sign and the scale
drawing are two different-sized triangles with the
same angle measures
Focus on Higher Order Thinking
9 More than one triangle can be formed Two triangles
can be created by connecting the top of the 2-in
segment with the dashed line once in each spot
where the arc intersects the dashed line The
triangles are different but both have side lengths of
2 in and 1 1 __ 2 in and a 45deg angle not included
between them
10 The third side has a length of 15 in The third side
must be congruent to one of the other two sides
because the triangle is isosceles The third side
cannot measure 6 in because 6 + 6 is not greater
than 15 So the third side must measure 15 in
LESSON 83
Guided Practice
1 triangle or equilateral triangle
2 rectangle
3 triangle
4 rainbow-shaped curve
5 Sample answer Draw the figure and the plane
Independent Practice
6 Sample answer A horizontal plane results in cross
section that is a circle A plane slanted between
horizontal and vertical results in an oval cross
section A vertical plane through the cylinder results
in a rectangle A vertical plane along an edge of the
cylinder results in a line cross section
7 You would see circles or ovals with a cone but not
with a pyramid or prism
Focus on Higher Order Thinking
8 The plane would pass through the cube on a
diagonal from the top to the bottom of the cube
9 a It is a circle with a radius of 12 in
b The cross sections will still be circles but their
radii will decrease as the plane moves away from
the spherersquos center
10 The dimensions of two faces are 12 in by 8 in two
are 8 in by 5 in and two are 12 in by 5 in the
volume is 480 in 3
11 Sample answer If you think of a building shaped like
a rectangular prism you can think of horizontal
planes slicing the prism to form the different floors
Copyright copy by Houghton Mifflin Harcourt 54 All rights reserved
LESSON 84
Your Turn
5 Supplementary angles sum to 180deg Sample answer angFGA and angAGC
6 Vertical angles are opposite angles formed by two
intersecting lines
Sample answer angFGE and angBGC
7 Adjacent angles are angles that share a vertex and
one side but do not overlap Sample answer
mangFGD and mangDGC
8 Complementary angles are two angles whose
measures have a sum of 90deg Sample answer
mangBGC and mangCGD
9 Because mangFGE = 35deg and angFGE and angBGC are
vertical angles that means mangBGC = 35deg also
Because lines _
BE and _
AD intersect at right angles
mangBGD = 90deg so mangBGC + mangCGD = 90deg which means
mangBGC + mangCGD = 90deg 35deg + x = 90deg 35deg minus 35deg + x = 90deg minus 35deg x = 55deg
mangCGD = 55deg
10 angJML and angLMN are supplementary so their
measures sum to 180deg mangJML + mangLMN = 180deg 3x + 54deg = 180deg 3x + 54deg - 54deg = 180deg - 54deg 3x = 126deg
3x ___ 3 = 126deg ____
3
x = 42deg
mangJML = 3x = 3 ( 42deg ) = 126deg
11 Sample answer You can stop at the solution step
where you find the value of 3x because the measure
of angJML is equal to 3x
Guided Practice
1 angUWV and angUWZ are complementary angles
2 angUWV and angVWX are adjacent angles
3 angAGB and angDGE are vertical angles
so mangDGE = 30deg
4 mangCGD + mangDGE + mangEGF = 180deg 50deg + 30deg + 2x = 180deg 80deg + 2x = 180deg 2x = 100deg mangEFG = 2x = 100deg
5 mangMNQ + mangQNP = 90deg 3x - 13deg + 58deg = 90deg so 3x + 45deg = 90degThen 3x = 45deg and x = 15deg mangMNQ = 3x - 13deg = 3 ( 15deg ) - 13deg = 45deg - 13deg = 32deg
6 Sample answer Let mangS = x Write and solve an
equation ( x + 3x = 180deg ) to find x then multiply the
value by 3
Independent Practice
7 Sample answer angSUR and angQUR are adjacent
They share a vertex and a side
8 Sample answer angSUR and angQUP
9 Sample answer angTUS and angQUN
10 mangQUR = 139deg Sample answer angSUR and angSUP
are supplementary so mangSUP = 180deg - 41deg = 139deg angSUP and angQUR are vertical angles so they are
congruent and mangQUR = mangSUP = 139deg
11 mangRUQ is greater Sample answer angSUR and
angNUR are complementary so
mangNUR = 90deg - 41deg = 49deg mangTUR = 41deg + 90deg which is less than
mangRUQ = 49deg + 90deg
12 Because angKMI and angHMG are vertical angles their
measures are equal
mangKMI = mangHMG
84 = 4x
84 ___ 4 = 4x ___
4
x = 21deg
13 Because angKMH and angKMI are supplementary
angles the sum of their measures is 180deg mangKMH + mangKMI = 180deg x + 84 = 180
x + 84 - 84 = 180 - 84
x = 96
mangKMH = 96deg
14 Because angCBE and angEBF are supplementary
angles the sum of their measures is 180deg mangCBE + mangEBF = 180deg x + 62 = 180
x + 62 - 62 = 180 - 62
x = 118
mangCBE = 118deg
15 Because angABF and angFBE are complementary
angles the sum of their measures is 90deg mangABF + mangFBE = 90deg x + 62 = 90
x + 62 - 62 = 90 - 62
x = 28
mangABF = 28deg
16 Because angCBA and angABF are supplementary
angles the sum of their measures is 180deg mangABF = 28deg so
mangCBA + mangABF = 180deg x + 28 = 180 - 28
x + 28 - 28 = 152
mangCBA = 152deg
Copyright copy by Houghton Mifflin Harcourt 55 All rights reserved
17 If the two angles are complementary the sum of
their angles is 90degmangA + mangB = 90deg ( x + 4deg ) + x = 90deg 2x + 4deg = 90deg _ -4deg _ -4deg 2x = 86deg
2x ___ 2 = 86deg ___
2
x = 43degBecause x = mangB then mangB = 43deg and
mangA = 43deg + 4deg so mangA = 47deg
18 If the two angles are supplementary the sum of their
angles is 180degmangD + mangE = 180deg 5x + x = 180deg 6x = 180deg
6x ___ 6 = 180deg ____
6
x = 30degBecause x = mangE then mangE = 30deg and
mangD = 30deg x 5 so mangD = 150deg
19 If the two angles are complementary the sum of
their angles is 90deg When angles are divided into
minutes and seconds one apostrophe signifies a
minute and two apostrophes signifies a second
mangJ + mangK = 90deg0000
48deg268+ mangK = 90deg0000
_ -48deg268 _ -48deg268
mangK = 41deg3352
mangK = 41deg3352 or mangK = 41 degrees
33 minutes 52 seconds
Focus on Higher Order Thinking
20 Yes a parking lot can be built because the measure
of angle K is 180deg - ( 50deg + 90deg ) or 40deg which is
greater than 38deg
21 Disagree the sum of the measures of a pair of
complementary angles is 90deg So the measure of
each angle must be less than 90deg 119deg gt 90deg
22 a The sum of mangA and its complement will be 90deg Let x represent the complement
mangA + x = 90deg 77deg + x = 90deg _ -77deg = _ -77deg x = 13deg The complement of mangA has a measure of 13deg
and a complement of a complement of mangA
would have an angle equal to mangA or 77deg b A complement of a complement of an angle has
the same measure of the angle itself Let xdeg be
the measure of an angle The measure of a
complement of the angle is ( 90 - xdeg ) A complement of that angle has a measure of
( 90 - ( 90 - xdeg ) ) = ( 90 - 90 + xdeg ) = xdeg
MODULE 8
Ready to Go On
1
Living
roomKitchen Office Bedroom Bedroom Bathroom
Actual
ℓ times w ( ft ) 16 times 20 12 times 12 8 times 12 20 times 12 12 times 12 6 times 8
Blueprint
ℓ times w ( in ) 4 times 5 3 times 3 2 times 3 5 times 3 3 times 3 15 times 2
2 No The side lengths proposed are 8 cm 4 cm and
12 cm The sum of the measures of the two shorter
sides 4 + 8 = 12 So no such triangle can be
created
3 The longest side could be 15 cm because 20 cm is
too long given the lengths of the other sides
4 A circle is a possible cross section of a sphere
A point is another
5 A circle rectangle oval and line are possible cross
sections of a cylinder
6 mangBGC and mangFGE are vertical angles so
mangFGE = 50deg
7 If the two angles are complementary the sum of
their angles is 90deg mangS + mangY = 90deg
( 2 ( mangY ) - 30deg ) + mangY = 90deg 3 ( mangY ) - 30deg = 90deg _ +30deg = _ +30deg 3 ( mangY ) = 120deg
3 ( mangY ) ________ 3 = 120deg ____
3
mangY = 40deg
mangY = 40deg
8 Sample answer You can use scale drawings to plan
rooms or gardens
Copyright copy by Houghton Mifflin Harcourt 56 All rights reserved
MODULE 9 Circumference Area and Volume
Are You Ready
1 416
_ times 13
1248
_ +thinsp4160
5408
5408
2 647
_ times thinsp04
2588
2588
3 705
_ times thinsp94
2820
_ +thinsp63450
66270
6627
4 256
_ timesthinsp049
2304
_ +thinsp10240
12544
12544
5 1 __ 2 ( 14 ) ( 10 )
7 ( 10 )
70 i n 2
6 ( 35 ) ( 35 )
1225 ft 2
7 ( 8 1 __ 2 ) ( 6 )
17 ___ 1 2 sdot 6 3 __
1
51 i n 2
8 1 __ 2 ( 125 ) ( 24 )
1 __ 2 ( 24 ) ( 125 )
( 12 ) ( 125 )
15 m 2
LESSON 91
Your Turn
3 d = 11 cm
C = πd
C asymp 314 ( 11 )
C asymp 3454
The circumference is about 3454 cm
6 C = πd
44 asymp 314d
44 ____ 314
asymp d
d asymp 1401 yards
Divide the diameter of the garden by the digging
rate
1401 divide 7 = 2001
It takes Lars about 2 hours to dig across the garden
Guided Practice
1 d = 9 in
C asymp 314 ( 9 )
C asymp 2826 in
2 r = 7 cm
C = 2πr
C asymp 2 ( 22 ___ 7 ) ( 7 )
C asymp 44 cm
3 d = 25 m
C = πd
C asymp 314 ( 25 )
C asymp 785 m
4 r = 48 yd
C = 2πr
C asymp 2 ( 314 ) ( 48 )
C asymp 3014 yd
5 r = 75 in
C = 2πr
C asymp 2 ( 314 ) ( 75 )
C asymp 471 in
6 Find the diameter
C = πd
66 asymp 314d
66 ____ 314
asymp 314d _____ 314
21 asymp d
Find the cost
Carlos needs 21 + 4 = 25 feet of rope
25 times $045 = $1125
Carlos will pay $1125 for the rope
7 Because C = π yd and C = πd d = 1 yd then
r = 05 yd
d = 1 yd
8 Because C = 788 ft and C = 2πr
2πr = 788
2πr ___ 2π
= 788 ____ 2π
r asymp 788 _______ 2 ( 314 )
r asymp 1255 ft
d = 2r asymp 2 ( 1255 ft )
d asymp 2510 ft
9 d = 2r so r = d __ 2 asymp 34 ___
2
r asymp 17 in
C = πd asymp 314 ( 34 )
C = 1068 in
Copyright copy by Houghton Mifflin Harcourt 57 All rights reserved
10 Use the formula C = πd and substitute
314 for π and 13 for the diameter
Independent Practice
11 d = 59 ft
C = πd
C asymp 314 ( 59 )
C asymp 1853 ft
12 r = 56 cm
C = 2πr
C asymp 2 ( 22 ___ 7 ) ( 56 )
C asymp 352 cm
13 d = 35 in
C = πd
C asymp ( 22 ___ 7 ) ( 35 )
C asymp 110 in
14 Sample answer In exercises 12 and 13 the radius
or diameter is a multiple of 7
15 r = 94 ft
d = 2r = 2 ( 94 )
d = 188 ft
C = πd
C asymp 314 ( 188 )
C asymp 590 ft
16 d = 475 in
r = d __ 2 = 475 ____
2
r = 2375 in
C = πd
C asymp 314 ( 475 )
C asymp 14915 in
17 d = 18 in
r = d __ 2 = 18 ___
2
r = 9 in
C = πd
C asymp 314 ( 18 )
C asymp 5652 in
18 r = 15 ft
C = 2πr
C asymp 2 ( 314 ) ( 15 ) = 942 ft
The cost for edging is C times $075 per foot
so ( 942 ) ( 075 ) = 7065 or about $707
19 C = πd
C asymp ( 22 ___ 7 ) ( 63 )
C asymp 198 ft
The distance traveled is 12 times the
circumference of the Ferris wheel so
distance = 12 ( 198 ) or about 2376 ft
20 C = πd asymp 314 ( 2 )
C asymp 628 ft
Converting km to ft
2 km sdot ( 3280 ft _______
1 km ) = 6560 ft
6560 ft
_______ 628 ft
= 104459
The wheel makes about 1045 revolutions
21 The distance your friend walks is half the
circumference of the pond
1 __ 2 C = 1 __
2 πd asymp 1 __
2 sdot 314 ( 025 ) = 03925
Your friend walks approximately 03925 mi
The difference is 03925 - 025 = 01425
Your friend walks about 014 mi farther
22 Capitol Rotunda Dimensions
Height 180 ft
Circumference 3015 ft
Radius r = C ___ 2π asymp 3015
_______ 2 ( 314 )
asymp 48 ft
Diameter d = 2r = 2 ( 48 ) = 96 ft
Focus on Higher Order Thinking
23 The length of the fence is half the circumference
plus the diameter
1 __ 2 C = 1 __
2 πd asymp 1 __
2 sdot 314 ( 30 ) = 471
The total distance is 471 + 30 = 771 ft
The total cost is the length of fence times the cost
per linear foot
( 771 ft ) ( $925 _____
ft ) = $71318
It will cost about $71318
24 The circumference of the patio is
C = πd asymp 314 ( 18 ) = 5652 ft
Converting the length of one strand of lights from
inches to feet
( 54 in ) ( 1 ft _____ 12 in
) = 45 ft
To find the number of strands of lights divide the
circumference by the length of one strand
5652 ft _______ 45 ft
= 1256
Because Sam cannot buy a fraction of a strand he
must buy 13 strands
25 The distance is the difference in the circumferences
C inner
= πd asymp 314 ( 150 ) = 471 ft
The outer diameter is 150 ft + 2 ( 2 ft ) = 154 ft
C outer
= πd asymp 314 ( 154 ) = 48356 ft
The difference is 48356 - 471 = 1256 ft
It is about 1256 ft farther
26 No The circumference of the larger gear is about
πd asymp 314 ( 4 ) = 1256 inches The circumference of
the smaller gear is about πd asymp 314 ( 2 ) = 628
inches So the circumference of the larger gear is
628 inches more than the circumference of the
smaller gear
Copyright copy by Houghton Mifflin Harcourt 58 All rights reserved
27 Pool B about 057 m or 184 ft Sample answer
24 feet asymp 732 m so the diameter of Pool B is
greater and the circumference is greater
314 ( 75 ) - 314 ( 732 ) = 314 ( 018 ) asymp 057
057 m asymp 187 ft
LESSON 92
Your Turn
4 A = π r 2 A = π ( 10 ) 2
A asymp 314 ( 10 ) 2
A asymp 314 sdot 100
A asymp 314 f t 2
Guided Practice
1 r = d __ 2 = 14 ___
2 = 7 m
A = π r 2 A = π ( 7 ) 2
A asymp 314 ( 7 ) 2
A asymp 314 sdot 49
A asymp 1539 m 2
2 A = π r 2 A = π ( 12 ) 2
A asymp 314 ( 12 ) 2
A asymp 314 sdot 144
A asymp 4522 m m 2
3 r = d __ 2 = 20 ___
2 = 10 yd
A = π r 2 A = π ( 10 ) 2
A asymp 314 ( 10 ) 2
A asymp 314 sdot 100
A asymp 314 y d 2
4 A = π r 2 A = π ( 8 ) 2
A asymp 314 ( 8 ) 2
A asymp 314 sdot 64
A asymp 20096 i n 2
5 r = d __ 2 = 12 ___
2 = 6 cm
A = π r 2 A = π ( 6 ) 2
A asymp 314 ( 6 ) 2
A asymp 314 sdot 36
A asymp 11304 c m 2
6 r = d __ 2 = 13 ___
2 = 65 in
A = π r 2 A = π ( 65 ) 2
A asymp 314 ( 65 ) 2
A asymp 314 sdot 4225
A asymp 13267 i n 2
7 C = 4π = 2πr
4π ___ 2π
= 2πr ___ 2π
r = 2
A = π r 2 A = π ( 2 ) 2
A = 4π square units
8 C = 12π = 2πr
12π ____ 2π
= 2πr ___ 2π
r = 6
A = π r 2 A = π ( 6 ) 2
A = 36π square units
9 C = π __ 2 = 2πr
π __ 2 divide 2π = 2πr ___
2π
π __ 2 sdot 1 ___
2π = r
1 __ 4 = r
A = π r 2
A = π ( 1 __ 4 ) 2 = π ( 1 ___
16 )
A = π ___ 16
square units
10 A = π r 2 = 64π
π r 2 ___ π = 64π ____ π
r 2 = 64
r = 8
C = 2πr
= 2π ( 8 )
=16π yd
11 A = π r 2
Independent Practice
12 r = d __ 2 = 10 ___
2 = 5 in
A = π r 2 A = π ( 5 ) 2
A asymp 314 ( 5 ) 2
A asymp 314 sdot 25
A asymp 785 i n 2
13 A = π r 2 A = π ( 16 ) 2
A asymp 314 ( 16 ) 2
A asymp 314 sdot 256
A asymp 80384 c m 2
14 The area of the window is half the area of a circle of
diameter 36 in
r = d __ 2 = 36 ___
2 = 18 in
A semicircle
= 1 __ 2 π r 2
A semicircle
= 1 __ 2 π ( 18 ) 2
A semicircle
asymp 1 __ 2 ( 314 ) ( 18 ) 2
A semicircle
asymp 05 sdot 314 sdot 324
A asymp 50868 i n 2
Copyright copy by Houghton Mifflin Harcourt 59 All rights reserved
15 If the point ( 3 0 ) lies on the circle and the origin is
its center the radius of the circle is 3 units
A = π r 2 A = π ( 3 ) 2
A asymp 314 ( 3 ) 2
A asymp 314 sdot 9A asymp 2826 square units
16 The difference in areas is given by
A r = 75 mi
- A r = 50 mi
π ( 75 ) 2 - π ( 50 ) 2
= π ( 7 5 2 minus 5 0 2 ) = π ( 5625 minus 2500 ) = π ( 3125 ) asymp 98125
The area of the relayed signal is about 9813 mi 2
greater
17 The area of the field which is not reached by the
sprinkler is the area of the field minus the area
reached by the sprinkler or s 2 minus π r 2 where
s = 12 m and r is the radius of the circular area The
diameter of the circle is equal to a side of the field
12 m so the radius is 12 ___ 2 = 6 m So
s 2 minus π r 2 = 1 2 2 minus π ( 6 ) 2
= 144 minus π ( 36 )
asymp 144 minus 11304 = 3096
The area not reached by the sprinkler is
approximately 3096 m 2
18 No the area of the regular pancake is 4π in 2 and the
area of the silver dollar pancake is π in 2 so the area
of the regular pancake is 4 times the area of the
silver dollar pancake
19 No the top of the large cake has an area 9 times
that of the small cake The area of the top of the
large cake is 144π in 2 and that of the small cake is
16π in 2
20 Sample answer First find the radius of the circle by
using the formula C = 2πr Then substitute the
radius into the formula for the area of a circle
21 The 18-inch pizza is a better deal because it costs
about $20
_____ π ( 9 ) 2
asymp $008 or 8 cents per square inch
while the 12-inch pizza costs about $10
_____ π ( 6 ) 2
asymp $009
or 9 cents per square inch
22 a Because the bear can walk at a rate of 2 miles
per hour and was last seen 4 hours ago the
radius of the area where the bear could be found
is given by ( 2 miles per hour ) ( 4 hours ) = 8 miles
A = π r 2 = π ( 8 ) 2
= π ( 64 )
asymp 20096
The searchers must cover an area of about
201 mi 2
b The additional area is the difference in areas of
circles with radii ( 2 miles per hour ) ( 5 hours )
= 10 miles and the original 8 miles
A new
minus A old
= π ( 10 ) 2 - π ( 8 ) 2
= π ( 1 0 2 - 8 2 ) = π ( 100 - 64 )
= π ( 36 ) asymp 11304
The searchers would have to cover about 113 mi 2
more area
Focus on Higher Order Thinking
23 No the combined area is 2π r 2 while the area of a
circle with twice the radius is 4π r 2
24 The area is multiplied by a factor of n 2
25 To find the part that is the bullrsquos-eye take the ratio of
the area of the bullrsquos-eye to that of the whole target
The radius of the bullrsquos-eye is 3 __ 2 = 15 in and
the radius of the whole target is 15 ___ 2 = 75 in
A
bullrsquos-eye ________
A whole target
=
π ( 15 ) 2 ______
π ( 75 ) 2
= ( 15 ) 2
_____ ( 75 ) 2
= 225 _____ 5625
= 004
The bullrsquos-eye is 004 or 4 of the whole target
LESSON 93
Your Turn
2 The figure can be separated into a rectangle and
two right triangles
The dimensions of the large rectangle are
length = 8 + 3 = 11 ft width = 4 ft
The dimensions of the two small triangles are
base = 3 ft height = 2 ft ( upper triangle ) base = 3 ft height = 3 ft ( lower triangle ) The area of the rectangle is
A = ℓw = 11 sdot 4 = 44 f t 2
The area of the upper triangle is
A = 1 __ 2 bh = 1 __
2 sdot 3 sdot 2 = 3 f t 2
The area of the lower triangle is
A = 1 __ 2 bh = 1 __
2 sdot 3 sdot 3 = 45 f t 2
Therefore the total area of the figure is
44 + 3 + 45 = 515 f t 2
3 The figure can be separated into a square and a
semicircle
Each side of the square is equal to 10 m
The radius of the semicircle is half the diameter
or 10 ___ 2 = 5 m
The area of the square is
A = s 2 = 1 0 2 = 100 m 2
The area of the semicircle is
A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 5 ) 2
A asymp 1 __ 2 sdot 314 sdot 25
A asymp 3925 m 2
Therefore the approximate total area of the figure is
100 + 3925 = 13925 m 2
Copyright copy by Houghton Mifflin Harcourt 60 All rights reserved
4 The composite figure is made up of a rectangle and two
semicircles which can be combined to form one circle
The dimensions of the rectangle are
length = 5 ft width = 4 ft
The diameter of the circle is 4 ft so the radius is
4 __ 2 = 2 ft
The area of the rectangle is
A = ℓw = 5 sdot 4 = 20 f t 2
The area of the circle is
A = π r 2 A asymp 314 sdot ( 2 ) 2
A asymp 314 sdot 4A asymp 1256 f t 2
The approximate total area is the sum of these
two areas
20 + 1256 = 3256 f t 2
Because the glass costs $28 per square foot
multiply the total area by the cost per square foot
( 3256 f t 2 ) ( $28 ____
f t 2 ) = $91168
It will cost about $91168 to replace the glass
Guided Practice
1 Separate the figure into a triangle a rectangle and
a parallelogram
Find the area of each figure
For triangle A = 1 __ 2 bh = 1 __
2 ( 4 ) ( 2 ) = 4
For rectangle A = ℓw = ( 5 ) ( 3 ) = 15
For parallelogram A = bh = ( 5 ) ( 3 ) = 15
Triangle 4 cm 2 rectangle 15 cm
2 parallelogram
15 cm 2
Step 3 Find the area of the composite figure
4 + 15 + 15 = 34 cm 2
The area of the irregular shape is 34 cm 2
2 Method 1
A 1 = ℓw A
2 = ℓw
= 12 sdot 9 = 20 sdot 9 = 108 = 180
Total area = 288 c m 2
Method 2
A 1 = ℓw A
2 = ℓw
= 9 sdot 8 = 12 sdot 8 = 72 = 216
Total area = 288 c m 2
3 Separate the figure into a trapezoid with h = 5 ft
b 1 = 7 ft and b 2 = 4 ft and a parallelogram with
base = 4 ft and height = 4 ft
For trapezoid A = 1 __ 2 h ( b
1 + b
2 )
A = 1 __ 2 ( 5 ) ( 7 + 4 )
A = 1 __ 2 ( 5 ) ( 11 ) = 275 f t 2
For parallelogram A = bh = ( 4 ) ( 4 ) = 16 f t 2
Find the area of the composite figure
275 + 16 = 435 ft 2
Multiply the total area by the cost per square foot to
find the cost
( 435 f t 2 ) ( $225 _____
f t 2 ) = $9788
4 The first step is separating the composite figure into
simpler figures
Independent Practice
5 Area of square A = s 2 = 2 6 2 = 676 i n 2
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 13 ) 2
A asymp 1 __ 2 sdot 314 sdot 169
A asymp 26533 i n 2
The approximate total area is the sum
676 + 26533 = 94133 in 2
6 a The floor of the closet is a composite of a
rectangle with length = 10 ft and width = 4 ft and
a triangle with base = 6 ft and height = 3 + 4 = 7 ft
Area of rectangle A = ℓw = 10 sdot 4 = 40 f t 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 6 sdot 7
A = 1 __ 2 sdot 42
A = 21 f t 2
The total area is the sum
40 + 21 = 61 f t 2
b The cost is the area multiplied by the cost per
square foot
( 61 f t 2 ) ( $250 _____
f t 2 ) = $15250
7
O 42-2-4
2
-4
y
A (-2 4) B (0 4)
C (2 1)D (5 1)
E (5 -2)F (-2 -2)
The area can be thought of as a composite of a
trapezoid and a rectangle
For trapezoid Let b 1 of the trapezoid be the
segment from the point ( -2 1 ) point C with length
4 units b 2 be from point A to point B with length
2 units and height equal to 3 units
For rectangle The corners of the rectangle are
( -2 1 ) D E and F Let the length of the rectangle
be 7 units and the width be 3 units
Area of trapezoid
A = 1 __ 2 h ( b
1 + b
2 )
A = 1 __ 2 ( 3 ) ( 4 + 2 )
A = 1 __ 2 ( 3 ) ( 6 ) = 9 square units
Copyright copy by Houghton Mifflin Harcourt 61 All rights reserved
Area of rectangle A = ℓw
A = 7 sdot 3 A = 21 square units
The total area is the sum
9 + 21 = 30 square units
8 The field is a composite of a square with side = 8 m
a triangle with base = 8 m and height = 8 m and a
quarter of a circle with radius = 8 m
Area of square A = s 2 = 8 2 = 64 m 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 8 sdot 8
A = 1 __ 2 sdot 64
A = 32 m 2
Area of quarter circle A = 1 __ 4 π r 2
A asymp 1 __ 4 sdot 314 sdot ( 8 ) 2
A asymp 1 __ 4 sdot 314 sdot 64
A asymp 5024 f t 2
The approximate total area is the sum
64 + 32 + 5024 = 14624 m 2
9 The bookmark is a composite of a rectangle with
length = 12 cm and width = 4 cm and two
semicircles which combine to form a full circle with
diameter = 4 cm so radius = 4 __ 2 = 2 cm
Area of rectangle A = ℓw = 12 sdot 4 = 48 c m 2
Area of circle A = π r 2 A asymp 314 sdot ( 2 ) 2
A asymp 314 sdot 4 A asymp 1256 c m 2
The approximate total area is the sum
48 + 1256 = 6056 cm 2
10 The pennant is a composite of a rectangle with
length = 3 ft and width = 1 ft and a triangle with
base = 1 ft and height = 1 ft
Area of rectangle A = ℓw = 3 sdot 1 = 3 f t 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 1 sdot 1
A = 1 __ 2 sdot 1
A = 05 f t 2
The area of one pennant is the sum
3 + 05 = 35 ft 2
Alex is making 12 pennants so the total area of all
12 pennants is 12 sdot 35 = 42 ft 2
The cost for the pennants will be the total area times
the fabric cost per square foot
( 42 f t 2 ) ( $125 _____
f t 2 ) = $5250
11 The area of the square is the total area minus the
area of triangle
325 ft 2 - 75 ft 2 = 25 ft 2
The area of a square is A = s 2 so s 2 = 25 f t 2
Because 5 sdot 5 = 25 the length of each side of the
square is 5 ft
Focus on Higher Order Thinking
12 The area of the garden can be found from counting
squares there are 18 full squares and 4 half-squares
for a total of 20 square units Each square unit will
grow about 15 carrots So Christina will grow about
20 ( 15 ) or 300 carrots
13 To find the length of the three sides of the square
subtract the lengths of the two sides of the triangle
from the perimeter The total length of three sides of
the square is 56 - 20 = 36 in Divide by 3 to find
that the length of one side and the base of the
triangle is equal to 12 in The total area of the figure
is the area of the square plus the area of the
triangle
Area of square A = s 2 = 1 2 2 = 144 i n 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 12 sdot 8
A = 1 __ 2 sdot 96
A = 48 i n 2
The total area is the sum
144 + 48 = 192 in 2
14 Think of the scarf as a rectangle minus two
semicircles The rectangle has length = 28 in and
width = 15 in The circle has diameter = 15 in so
its radius is 15 ___ 2 = 75 in
Area of rectangle A = ℓw = 28 sdot 15 = 420 i n 2
Area of circle A = π r 2 A asymp 314 sdot ( 75 ) 2
A asymp 314 sdot 5625
A asymp 176625 i n 2
The total area is the difference
420 - 176625 = 243375 in 2 or 243 3 __
8 i n 2
15 a The window is a composite of a square and a
semicircle Because each square in the window
has an area of 100 in 2 the length of each side is
10 in So each side of the square portion of the
entire window has length 10 sdot 4 = 40 in The
diameter of the semicircle is also 40 in so
the radius is 40 ___ 2 = 20 in
Area of square A = s 2 = 4 0 2 = 1600 i n 2
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 20 ) 2
A asymp 1 __ 2 sdot 314 sdot 400
A asymp 628 i n 2
The approximate total area is the sum
1600 + 628 = 2228 in 2
Copyright copy by Houghton Mifflin Harcourt 62 All rights reserved
b The shade is a composite of a rectangle and
a semicircle The length of the rectangle is equal
to the length of one side of the square portion
of the window plus 2 sdot 4 inches for a total of
40 + 2 sdot 4 = 48 in
The height of the rectangular portion of the shade
is equal to 4 times the length of one side of the
square portion of the window plus 4 inches for a
total of 40 + 4 = 44 in
The diameter of the semicircle at the top is the
same as the length of the bottom of the shade
48 in so the radius = 48 ___ 2 = 24 in
Area of rectangle A = ℓw = 48 sdot 44 = 2112 i n 2
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 24 ) 2
A asymp 1 __ 2 sdot 314 sdot 576
A asymp 90432 i n 2
The approximate total area of the shade is
the sum
2112 + 90432 asymp 3016 in 2
LESSON 94
Your Turn
3 Find the area of a base
B = l times w
= 9 times 2
= 18 square inches
Find the perimeter of the base
P = 2 ( 9 ) + 2 ( 2 )
= 18 + 4 = 22 inches
Find the surface area
S = Ph + 2B
S = 22 ( 1 1 __ 2 ) + 2 ( 18 )
= 33 + 36
= 69
The surface area of the box is 69 square inches
4 Find the area of the base of the larger prism
B = times w
= 12 times 12
= 144 square inches
Find the perimeter of the base
P = 4 ( 12 )
= 48 inches
Find the surface area of the larger prism
S = Ph + 2B
S = 48 ( 12 ) + 2 ( 144 )
= 576 + 288
= 864 square inches
Find the area of the base of the smaller prism
B = l times w
= 8 times 8
= 64 square inches
Find the perimeter of the base
P = 4 ( 8 )
= 32 inches
Find the surface area of the smaller prism
S = Ph + 2B
S = 32 ( 8 ) + 2 ( 64 )
= 256 + 128
= 384 square inches
Add the surface areas of the two prisms and
subtract the areas not stained (the bottom of the
larger prism and the smaller prism and an equal
area of the top of the larger prism where the smaller
prism sits) Surface area = 864 + 384 - 144 - 64
- 64 = 976 The surface area of the part of the plant
stand that she will stain is 976 square inches
Guided Practice
1 Perimeter of base = 5 + 5 + 8 = 18
Perimeter of base = 18 ft
Height = 7 ft
Base area = 1 __ 2 ( 3 ) ( 8 ) = 12 ft 2
Surface area
S = ( 18 ft ) ( 7 ft ) + 2 ( 12 ft 2 ) = 150 ft 2
2 Find the area of a base of the cube
B = l times w
= 25 times 25
= 625 m 2
Find the perimeter of the base of the cube
P = 4 ( 25 )
= 10 m
Find the surface area of the cube
S = Ph + 2B
S = 10 ( 25 ) + 2 ( 625 )
= 25 + 125
= 375
Surface area of cube
S = 375 m 2
Find the area of a base of the rectangular prism
B = l times w
= 11 times 9
= 99 m 2
Find the perimeter of the base of the rectangular
prism
P = 2 ( 11 ) + 2 ( 9 )
= 22 + 18
= 40 m
Find the surface area of the rectangular prism
S = Ph + 2B
S = 40 ( 7 ) + 2 ( 99 )
= 280 + 198
= 478
Surface area of rectangular prism
S = 478 m 2
Find the overlapping area the bottom of the cube
A = ( 25 ) ( 25 ) = 625
Overlapping area A = 625 m 2
Surface area of composite figure
= 375 + 478 -2 ( 625 ) = 503 m 2
3 Find the surface area of each of the prisms that
make up the solid Add the surface areas and
subtract the areas of any parts that are not on the
surface
Copyright copy by Houghton Mifflin Harcourt 63 All rights reserved
Independent Practice
4 Find the area of a base
B = l times w
= 10 times 3
= 30 in 2
Find the perimeter of the base
P = 2 ( 10 ) + 2 ( 3 )
= 20 + 6
= 26 in
Find the surface area
S = Ph + 2B
S = 26 ( 4 ) + 2 ( 30 )
=104 + 60
= 164 in 2
She needs 164 in 2 of wrapping paper
5 Find the area of the base
B = l times w
= 20 times 15
= 300 cm 2
Find the perimeter of the base
P = 2 ( 20 ) + 2 ( 15 )
= 40 + 30
= 70 cm
Find the surface area of the box
S = Ph + 2B
S = 70 ( 9 ) + 2 ( 300 )
= 630 + 600
= 1230 cm 2
Find the surface area of the top and sides
1230 - 300 = 930 cm 2
Find the area of a glass tile
Area of tile = 5 times 5 = 25 mm 2
Convert cm 2 to mm
2
930 cm 2 times 100 mm
2 ________
1 cm 2 = 93000 mm
2
Find the number of tiles needed
93000 divide 25 = 3720
3720 tiles are needed
6 Find the area of the L-shaped base
Area of L-shape = 2 times 1 + 3 times 1
= 2 + 3 = 5 in 2
Find the perimeter of the L-shaped base
Perimeter = 3 + 3 + 1 + 2 + 2 + 1
= 12 in
Find the surface area
S = Ph + 2B
S = 12 ( 3 ) + 2 ( 5 )
= 36 + 10
= 46 in 2
The surface area of each brace is 46 in 2
7 Find the area of the triangular prism
Perimeter = 25 + 25 + 3 = 8 ft
Base area = 1 __ 2 ( 2 ) ( 3 ) = 3 ft 2
Surface area = Ph + 2B
= 8 ( 4 ) + 2 ( 3 )
= 32 + 6 = 38 ft 2
Find the area of the rectangular prism
Perimeter = 2 ( 3 ) + 2 ( 4 ) = 14 ft
Base area = 3 times 4 = 12 ft 2
Surface area = Ph + 2B
= 14 ( 2 ) + 2 ( 12 )
= 28 + 24 = 52 ft 2
Add the surface areas of the two prisms and
subtract the parts not on the surface
Surface area = 38 + 52 - 12 - 12 = 66 ft 2
The total surface area of the doghouse is 66 ft 2
8 Treat the figure as ( 1 ) a composite of two triangular
prisms and one rectangular prism or ( 2 ) a prism
with a base that is a trapezoid
9 Find the area of the trapezoid base
Area of trapezoid = 1 __ 2 ( b
1 + b
2 ) h
1 __ 2 ( 16 + 48 ) 12 = 384 in
2
Find the perimeter of the base
P = 48 + 20 + 16 + 20 = 104 in
Find the surface area
S = Ph + 2B
S = 104 ( 24 ) + 2 ( 384 )
= 2496 + 768
= 3264 in 2
The surface area of the ramp is 3264 in 2
10 Find the area of the base of the larger prism
B = l times w
= 7 times l
= 7 ft 2
Find the perimeter of the base
P = 2 ( 7 ) + 2 ( 1 )
= 14 + 2
= 16 ft
Find the surface area of the larger prism
S = Ph + 2B
S = 16 ( 2 ) + 2 ( 7 )
= 32 + 14
= 46 f t 2
Find the area of the base of the smaller prism
B = l times w
= 1 times 1
= 1 ft 2
Find the perimeter of the base
P = 2 ( 1 ) + 2 ( 1 )
= 2 + 2 = 4 ft
Find the surface area of the smaller prism
S = Ph + 2B
S = 4 ( 3 ) + 2 ( 1 )
= 12 + 2
= 14 ft 2
Add the surface areas of the two prisms and
subtract the parts not on the surface
Surface area = 46 + 14 - 1 - 1 = 58 ft 2
The surface area of the stand is 58 ft 2
11 Find the number of cans of paint needed
58 divide 25 = 232
It takes 2 full cans and 1 partial can so 3 cans are
needed
Find the cost of 3 cans of paint
3 times 679 = 2037
No they need 3 cans which will cost $2037
Copyright copy by Houghton Mifflin Harcourt 64 All rights reserved
12 Find the area of the base of the box
B = l times w
= 27 times 24
= 648 cm 2
Find the perimeter of the base
P = 2 ( 27 ) + 2 ( 24 )
= 54 + 48
= 102 cm
Find the surface area of the box
S = Ph + 2B
S = 102 ( 10 ) + 2 ( 648 )
= 1020 + 1296
= 2316 cm 2
2316 cm 2 will be covered with paper
13 Area of the original base B = l times w
Area of the new base = 2l times 2w = 4lw = 4B
Perimeter of the original = 2l + 2w
Perimeter of the new = 2 ( 2l ) + 2 ( 2w ) =
2 ( 2l + 2w ) = 2P
Original S = Ph + 2B
New S = 2Ph + 2 ( 4B )
No Ph doubles and 2B quadruples S more than
doubles
Focus on Higher Order Thinking
14 Find the area of the base of the prism
B = l times w
= 25 times 25
= 625 ft 2
Find the perimeter of the base
P = 4 ( 25 )
= 10 ft
Find the surface area of the prism
S = Ph + 2B
S = 10 ( 35 ) + 2 ( 625 )
= 35 + 135
= 485 ft 2
Find the surface area less the area of the bottom
surface of the prism
485 - 625 = 4225 ft 2
Find what percent of the surface area less the area
of the bottom is compare to the total surface area
4225 _____ 485
times 100 asymp 87
Sample answer She would be painting about 87
of the total surface area so she will use about 87
of the total amount of paint
15
Circumference ofcircle πd = πtimes4
r = 2 in
9 in
Find the area of the circle base
A = πr 2
asymp 31 4 ( 2 ) 2 = 1256 in 2
Find the circumference of the circle
C = πd
asymp 314 ( 4 ) = 1256 in 2
Find the area of the rectangle
Area asymp 9 times 1256 = 11304 in 2
Find the surface area of the cylinder
S = Ch + 2B
asymp 1256 ( 9 ) + 2 ( 1256 ) = 13816 in 2
Round to the nearest tenth 1382 in 2
The surface area of the oatmeal box is
approximately 1382 in 2
Find the amount of cardboard for 1500 boxes
1500 times 1382 = 207300 in 2
Convert square inches to square feet and round to
the nearest whole number
( 207300 in 2 ) 1 ft 2 _______
144 in 2 asymp 1440 ft 2
It would take about 1440 ft 2 of cardboard
16 Each face has 9 squares 1 cm by 1 cm so S =
54 cm 2 The surface area stays the same when one
or more corner cubes are removed ( Fig 2 3 ) because the number of faces showing is still the
same In Fig 4 S increases because 2 more faces
show
LESSON 95
Your Turn
2 Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 24 ) 7
= 84 m 2
Find the volume of the prism
V = Bh
= ( 84 ) ( 22 )
= 1848 m 3
The volume of the prism is 1848 m 3
5 Find the base area B of the trapezoidal prism
B = 1 __ 2 ( b 1 + b 2 ) h
= 1 __ 2 ( 8 + 12 ) 10
= 1 __ 2 ( 20 ) 10 = 100 cm
2
Find the volume of the prism
V = Bh
= ( 100 ) ( 22 )
= 2200 cm 3
The volume of the prism is 2200 cm 3
7 Find the volume of each prism
Find the base area B of the rectangular prism
B = bh
= ( 13 ) 13
= 169 in 2
Find the volume of the rectangular prism
V = Bh
= ( 169 ) ( 30 )
= 5070 in 3
Copyright copy by Houghton Mifflin Harcourt 65 All rights reserved
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 9 ) 13
= 585 in 2
Find the volume of the triangular prism
V = Bh
= ( 585 ) ( 30 )
= 1755 in 3
Find the sum of the volumes
5070 + 1755 = 6825 in 3
The volume of the composite figure is 6825 in 3
Guided Practice
1 B = 1 __ 2 bh = 1 __
2 ( 8 ) ( 3 ) = 12 ft 2
V = Bh = ( 12 times 7 ) ft 3 = 84 ft 3
2 B = 1 __ 2 ( b 1 + b 2 ) h = 1 __
2 ( 15 + 5 ) 3 = 30 m
2
V = Bh = ( 30 times 11 ) m 3 = 330 m 3
3 Find the base area B of the rectangular prism
B = bh
= ( 4 ) 6 = 24 ft 2
Find the volume of the rectangular prism
V = Bh
= ( 24 ) ( 12 ) = 288 ft 3
The volume of the rectangular prism = 288 ft 3
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 6 ) 4 = 12 ft 2
Find the volume of the triangular prism
V = Bh
= ( 12 ) ( 6 ) = 72 ft 3
The volume of the triangular prism = 72 ft 3
Find the sum of the volumes
288 + 72 = 360 ft 3
The volume of the composite figure = 360 ft 3
4 Find the base area B of the rectangular prism
B = bh
= ( 40 ) ( 50 ) = 2000 ft 2
Find the volume of the rectangular prism
V = Bh
= ( 2000 ) ( 15 ) = 30000 ft 3
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 40 ) ( 10 ) = 200 ft 2
Find the volume of the triangular prism
V = Bh
= ( 200 ) ( 50 ) = 10000 ft 3
Find the sum of the volumes
30000 + 10000 = 40000 ft 3
The volume of the barn is 40000 ft 3
5 Find the base area B of the trapezoidal prism
B = 1 __ 2 ( b 1 + b 2 ) h
= 1 __ 2 ( 10 + 12 ) 5
= 1 __ 2 ( 22 ) 5 = 55 cm
2
Find the volume of the trapezoidal prism
V = Bh
= ( 55 ) ( 7 ) = 385 cm 3
The volume of the container is 385 cm 3
6 Find the volume of each prism using the formula
V = Bh Then add the volumes of all the prisms
Independent Practice
7 The area of the base of the prism is given 35 in 2
Find the volume of the prism
V = Bh
= ( 35 ) ( 5 ) = 175 in 3
The volume of the trap is 175 in 3
8 The shape of the ramp is triangular prism
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 7 ) ( 6 ) = 21 in
2
Find the volume of the triangular prism
V = Bh
= ( 75 ) ( 7 ) = 525 in 3
The volume of the ramp is 525 in 3
9 Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 8 ) ( 4 ) = 16 ft 2
Find the volume of the triangular prism
V = Bh
= ( 16 ) ( 24 ) = 384 ft 3
The space contained within the goal is 384 ft 3
10 Find the base area B of the trapezoidal prism
B = 1 __ 2 ( b 1 + b 2 ) h
= 1 __ 2 ( 7 + 5 ) 4
= 1 __ 2 ( 12 ) 4 = 24 in
2
Find the volume of the trapezoidal prism
V = Bh
= ( 24 ) ( 8 ) = 192 in 3
The volume of the gift box is 192 in 3
11 Find the volume of the triangular prism
V = Bh
= ( 20 ) ( 15 ) = 300 in 3
The units for volume are incorrect the volume is
300 cubic inches
12 The area of the base of the hexagonal prism is
given B = 234 in 3
Find the volume of the hexagonal prism
V = Bh
= ( 234 ) ( 3 ) = 702 in 3
Copyright copy by Houghton Mifflin Harcourt 66 All rights reserved
Find the base area B of the rectangular prism
B = bh
= ( 3 ) ( 3 ) = 9 in 2
Find the volume of the rectangular prism
V = Bh
= ( 9 ) ( 3 ) = 27 in 3
Find the sum of the volumes
702 + 27 = 972 in 3
The volume of the figure is 972 in 3
13 Find the base area B of the larger rectangular prism
B = bh
= ( 75 ) 375 = 28125 m 2
Find the volume of the larger rectangular prism
V = Bh
= ( 28125 ) ( 75 ) asymp 21094 cm 3
Find the base area B of the smaller rectangular
prism
Find the measure of the base
15 - 75 = 75
Find the base area B of the larger rectangular prism
B = bh
= ( 75 ) 375 = 28125 m 2
Find the volume of the smaller rectangular prism
V = Bh
= ( 28125 ) ( 375 ) asymp 10547 cm 3
Find the sum of the volumes of the prisms
21094 + 10547 = 31641 m 3
The volume of the figure rounded to the nearest
hundredth is 31641 m 3
14 Find the volume of the hexagonal candle
V = Bh
= ( 21 ) ( 8 ) = 168 cm 3
Find the amount of wax Josie would have after
making the hexagonal candle
260 - 168 = 92 cm 3
Find the volume of the triangular candle
V = Bh
= ( 7 ) ( 14 ) = 98 cm 3
Find the amount of wax Josie would have after
making the hexagonal candle
260 - 168 = 92 cm 3
Find the area of the base of a triangular candle with
a height of 14 cm
V = Bh
92 = B ( 14 )
92 ___ 14
= B ( 14 ) _____ 14
6 8 ___ 14
= B asymp 657
No the area of the base of the triangular candle
must be less than or equal to about 657 cm 2
15 The base of trapezoidal prism is given 36 in 2 Find
the volume of the trapezoidal prism
V = Bh
= ( 36 ) ( 5 ) = 180 in 3
The base of triangular prism is given 32 in 2
Find the volume of the trapezoidal
prism V = Bh
= ( 32 ) ( 6 ) = 192 in 3
Triangular prism you get 192 in 3 for the same price
you would pay for 180 in 3 with the trapezoidal prism
Focus on Higher Order Thinking
16 Find the area of the base of the trapezoidal prism
V = Bh
286 = B ( 8 )
286 ____ 8 = B ( 8 )
3575 = B
Find the missing dimension of the base of the
trapezoidal prism
1 __ 2 ( 2 + b 2 ) 13 = 3575
1 __ 2 ( 2 + b 2 ) ( 13 ___
13 ) = 3575 _____
13
( 2 ) 1 __ 2 ( 2 + b 2 ) = ( 2 ) 275
2 + b 2 = 55
_ -2 _ -2
b 2 = 35 ft
The missing dimension is 35 ft
17 Find the area of the base of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 10 ) 6 = 30 cm
2
Find the volume of the triangular prism
V = Bh
= ( 30 ) ( 25 ) = 75 cm 3
Find the mass of the doorstop
mass asymp ( V in cm 3 ) ( 86 g
_____ cm
3 )
asymp ( 75 cm 3 ) ( 86 g
_____ cm
3 ) = 645 g
The volume of the doorstop is 75 cm 3 The mass is
about 645 g
18 If both the base and height of the triangular base are
tripled the area of the base is multiplied by 9
Tripling the height of the prism as well means the
volume of the prism is multiplied by 27
19 Use the formula for the volume of a trapezoidal
prism to find a set of dimensions that have a volume
of 120 cm 3
V = Bh
V = [ 1 __ 2 ( b 1 + b 2 ) h 1 ] h 2
120 ≟ [ 1 __ 2 ( 2 + 6 ) 4 ] 75
= [ 1 __ 2 ( 8 ) 4 ] 75
= [ 16 ] ( 75 ) = 120
Try another set of dimensions in the formula
V = Bh
V = [ 1 __ 2 ( b 1 + b 2 ) h 1 ] h 2
120 ≟ [ 1 __ 2 ( 1 + 7 ) 25 ] 12
= [ 1 __ 2 ( 8 ) 25 ] 12
= [ 10 ] 12 = 120
Copyright copy by Houghton Mifflin Harcourt 67 All rights reserved
Sample answers ( 1 ) height of trapezoid = 4 cm
base lengths = 2 cm and 6 cm height of prism
= 75 cm ( 2 ) height of trapezoid = 25 cm base
lengths = 1 cm and 7 cm height of prism = 12 cm
MODULE 9
Ready to Go On
1 r = 7 m A = π r 2 C = 2πr A asymp 314 sdot ( 7 ) 2
C asymp 2 sdot 314 sdot 7 A asymp 314 sdot 49
C asymp 4396 m A asymp 15386 m 2
2 d = 12 cm d = 6 cm so r = 12 ___ 2 = 6 ft
C = πd A = π r 2 C asymp 314 ( 12 ) A asymp 314 sdot ( 6 ) 2
C asymp 3768 cm A asymp 314 sdot 36
A asymp 11304 ft 2
3 The figure is a composite of a semicircle with
diameter = 16 m so radius is 16 ___ 2 = 8m and a
triangle with base = 16 m and height = 10 m
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 8 ) 2
A asymp 1 __ 2 sdot 314 sdot 64
A asymp 10048 m 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 16 sdot 10
A = 1 __ 2 sdot 160
A = 80 m 2
The total area is the sum
80 + 10048 = 18048 m 2
4 The figure is a composite of a parallelogram with
base = 20 cm and height = 45 cm and a rectangle
with length = 20 cm and height = 55 cm
Area of parallelogram A = bh
A = 20 sdot 45
A = 90 c m 2
Area of rectangle
A = ℓw = 20 sdot 55 = 110 c m 2
The total area is the sum
90 + 110 = 200 cm 2
5 Find the area of the triangular base
Area of triangle = 1 __ 2 bh
1 __ 2 ( 4 ) 3 = 6 cm 2
Find the perimeter of the base
P = 3 + 4 + 5 = 12 cm
Find the surface area
S = Ph + 2B
S = 12 ( 10 ) + 2 ( 6 )
thinsp=120 + 12
thinsp= 132 cm 2
Find the volume of the prism
V = Bh
= ( 6 ) 10
= 60 cm 3
6 Find the area of the composite base formed by a
rectangle and a triangle
Area of triangle = 1 __ 2 bh
1 __ 2 ( 4 ) 15 = 3 yd 2
Area of rectangle = bh
( 4 ) 2 = 8 yd 2
Area of the composite base 3 + 8 = 11 yd 2
Find the perimeter of the composite base
P = 4 + 2 + 25 + 25 + 2 = 13 yd
Find the surface area
S = Ph + 2B
S = 13 ( 25 ) + 2 ( 11 )
thinsp= 325 + 22
thinsp= 545 yd 2
The area of the base of the pentagonal prism
is given
B = 234 yd 3
Find the volume of the prism
V = Bh
= ( 11 ) 25
= 275 yd 3
7 Sample answer You can use a composite figure to
model a room then find surface area to decide how
much paint you need to paint the room
Copyright copy by Houghton Mifflin Harcourt 68 All rights reserved
Solutions KeyStatistics
unit
5MODULE 10 Random Samples and Populations
Are You Ready
1 x ___16
=45___40
40x=720
40x ____40
=720____40
x=18
2 x __5=1__
4
4x=5
4x ___4
=5__4
x=5__4=125
3 25___10
=x ___10
125=10x
125____10
=10x ____10
125=x
4 x __6
=2__9
9x= 12
9x ___9
=12___9
x=12___9=4__
3
5 4748495152575960range=60-47=13
6 4566689121213range=13-4=9
7 95979799100106108115range=115-95=20
8 121319273539476671range=71-12=59
9 mean=3+5+7+3+6+4+8+6+9+5_________________________________10
=56
10 mean=81+94+113+67+62+75____________________________6
=82
LESSON 101
Your Turn
4 Yeseveryemployeehadanequalchanceofbeingselected
5 Thequestionisbiasedsincecatsaresuggested
6 ThequestionisnotbiasedItdoesnotleadpeopletopickaparticularseason
Guided Practice
1 Method1ASampleanswer
Random Sample of Seventh Grade Male Students
Student Shoe SizeArturo 75
Jimmy 80
Darnell 90
Ping 75
Zach 85
Jamar 80
BSampleanswer
75+80+90+75+85+80___________________________6
=485____6
asymp81
Meanasymp81
Method2ASampleanswer
Student Shoe Size Student Shoe SizeReggie 85 Ling 85
Stan 80 Marcus 90
Alejandro 90 Tio 85
BSampleanswer
85+80+90+85+90+85____________________________6
=515____6 =86
Mean=size86
2Method1producesresultsthataremorerepresentativeoftheentirestudentpopulationbecauseitisarandomsample
3 Method2producesresultsthatarelessrepresentativeoftheentirestudentpopulationbecauseitisabiasedsample
4 YesSampleanswerWhatisyourfavoritecolor
5 Selectarandomsampleofsufficientsizethatrepresentsthepopulationandaskeachparticipantunbiasedquestions
Independent Practice
6 SampleanswerPaulrsquossamplewasbiasedMaybehisfriendsstudiedmorethanothers
7 SampleanswerNancyrsquossampledidnotincludeasmanystationsThereportcouldincludestationsnationwide
8 ItisabiasedsampleStudentswhoarenrsquotontheteamwonrsquotbeselected
CopyrightcopybyHoughtonMifflinHarcourt 69 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U5M10indd 69 103113 216 AM
9 Itisbiasedbecausestudentswhoarenrsquotinthatclasswonrsquotbeselected
10 Itisarandomsamplebecauseallseventhgradershaveanequalchanceofbeingselected
11 Itisarandomsamplebecausetheorganizationselectsnamesatrandomfromallregisteredvoters
12 Itisbiasedbecausebasketballismentioned
13 Jaersquosquestionisnotbiasedsinceitdoesnotsuggestatypeofarttostudents
Focus on Higher Order Thinking
14 CollinrsquosmethodbetterrepresentstheentirestudentpopulationbecauseheusedarandomsampleKarlrsquosmethodpickedpeoplethatcouldallbefriendsthatgotofootballgamestogetherThesamplemaynotbestrepresenttheentirestudentpopulation
15 a Every10thstudentoutof600meansthatBarbarasurveyed60studentsThiswasarandomsample
b 35___60
= x ____100
xasymp58
Thepercentis58____100
=58
ItappearsreasonablebecauseBarbarausedarandomsampleandsurveyedasignificantpercentofthestudents
16 CarloiscorrectTherearemanyvalidwaystoselectarepresentativesamplefromapopulation
LESSON 102
Your Turn
5 damagedMP3sinsample
______________________sizeofsample
=damagedMP3sinpopulation
________________________sizeofpopulation
6___50
= x_____3500
6sdot70______50sdot70
= x _____3500
420_____3500
= x_____3500
x=420420damagedMP3s
Guided Practice
1
6 7 8 9 10 11 12 13 14 1550 1 2 3 4
2 Orderthedatafindtheleastandgreatestvaluesthemedianandthelowerandupperquartiles
6 7 7 107 114 4 54
Leastvalue
4
Lower quartile
4
Median
65
Upper quartile
7
Greatestvalue11
Drawaboxplot
10 1550
3 Themostcommonagesofchildrenthatusethelibraryare4and7
4 Therangeofagesofchildrenthatusethelibraryisfrom4to11
5 Themedianageofchildrenthatusethelibraryis65
6 defectivephonesinsample
______________________sizeofsample
=defectivephonesinpopulation
_________________________sizeofpopulation
4___60
= x_____4200
4sdot70______60sdot70
= x_____4200
280_____4200
= x_____4200
x=280About280smartphonesintheorderarelikelytobedefective
7 infectedelkinsample
__________________sizeofsample
=infectedelkinpopulation
____________________sizeofpopulation
8___50
= x_____4500
8sdot90______50sdot90
= x_____4500
720_____4500
= x_____4500
x=720About720elkarelikelytobeinfected
8 YoucansetupproportionsusinginformationobtainedinarandomsampleofthepopulationForinstancethenumberofdefectivepartsinabatchcanbeusedtopredicthowmanypartswillbedefectiveinadifferent-sizebatch
divide060
divide060
CopyrightcopybyHoughtonMifflinHarcourt 70 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U5M10indd 70 103113 218 AM
Independent Practice
9 number of people with mispriced item in sample
_______________________________________ size of sample
=
number of people with mispriced item in one day
_______________________________________ size of population
4 ___ 50
= x ____ 600
4 sdot 12 ______ 50 sdot 12
= x ____ 600
48 ____ 600
= x ____ 600
x = 48
About 48 people are likely to have a mispriced item
10 number of boxes with at least one broken crayon in sample
_______________________________________________ size of sample
=
total number of boxes with at least one broken crayon
___________________________________________ size of population
2 ___ 20
= x ____ 130
2 sdot 65 _______ 20 sdot 65
= x ____ 130
13 ____ 130
= x ____ 130
x = 13
About 13 boxes will have at least one broken crayon
11 number of puppies
________________ size of sample
= total number of puppies
___________________ size of population
12 ___ 60
= x _____ 1200
12 sdot 20 ______ 60 sdot 20
= x _____ 1200
240 _____ 1200
= x _____ 1200
x = 240
About 240 puppies are in all of the cityrsquos animal
shelters
12 number of hawks building nests
__________________________ size of sample
= total number of hawks
__________________ size of population
12 ___ 72
= x ______ 10800
12 sdot 150 _______ 72 sdot 150
= x ______ 10800
1800
______ 10800
= x ______ 10800
x = 1800
About 1800 hawks are building nests
13 Yes this seems reasonable because 23 + 27
_______ 2 = 25
is the median of the data
14 Order the data
11 12 12 12 13 13 13 14 14 14 15 17 18 18
19 22
The total number of marathoners is 16 and of those
12 run 13 miles or more
12 ___ 16
= x ____ 100
12 sdot 625 ________ 16 sdot 625
= x ____ 100
75 ____ 100
= x ____ 100
x = 75
No The statement should say that 75 of female
marathoners run 13 or more miles a week
15
6 7 8 9 1050 1 2 3 4
Sample answer Most students at Garland have 2 or
fewer siblings
16 The box plot should show that at least 50 of the
ages are between 20 and 40 years of age
17 Kudrey needs to find the median and the lower and
upper quartiles and plot those points He assumed
all quartiles would be equally long when each
quartile represents an equal number of data values
Focus on Higher Order Thinking
18 Yes the least and greatest data values The median
and quartiles may or may not be actual data values
depending on how many values are in the data
19 A box plot Since every number is different a dot
plot would only have one dot over each value which
doesnrsquot give much information The box plot would
show the median the range and where data values
are concentrated if in fact they are
20 The typical salary at this company is $24000 the
median Yes it is misleading the average is thrown
off by the outlier value of $79000
Copyright copy by Houghton Mifflin Harcourt 71 All rights reserved
9 a 56 + 43 + 62 + 63 + 33 + 34 + 38 + 51 + 59 + 59
___________________________________________ 10
= 498
The average is 498 palms
b 498 sdot 64 = 31872
There are about 3187 palms on the entire farm
Focus on Higher Order Thinking
10 55 + 57 + 57 + 58 + 59 + 59 + 59 + 59 + 59 + 61 + 62 + 62 + 63 + 64 + 66
_________________________________________________________________ 15
= 60
The mean height is 60 inches Yes it is a good sample generated randomly and contains about 20 of the entire
population so it should provide a good estimate of the mean height of all competitors But taking more samples to
gauge the variability among the samples would make for a more valid estimate
11 Sample answer Answers will vary based on each studentrsquos results but should be about 13 or 14
12 Sample answer The larger the size of the random sample the more likely it is to represent the population
accurately
LESSON 103
Guided Practice
1 (1 600) 20
2 50 51 600
3 No In the sample 4 numbers (38 26 31 and 31)
represent defective batteries which is 20 of the
total In the shipment 50 out of 600 or about 8 of
the batteries are defective
4 Sample answer A too-small or non-random sample
is likely to pick unrepresentative data values
Independent Practice
5 Shop A 10 ___ 50
times 500 = 100
Shop B 23 ____ 100
times 500 = 115
Shop C 7 ___ 25
times 500 = 140
Shop A sells 100 whole-wheat bagels
Shop B sells 115 whole-wheat bagels
Shop C sells 140 whole-wheat bagels
6 From most to least likely B A C Shop Brsquos sample
would be the most representative because it
contained the most bagels Shop Crsquos sample would
be the least representative because it contained the
fewest bagels
7 She could use either the Shop A or Shop B sample
Both use a sufficient number of bagels to be
reasonably accurate The sample from Shop C uses
too few bagels to be accurate
8 2 of the 20 T-shirts in the sample are below quality
standards Because 2 ___ 20
times 1000 = 100 the predic-
tion would be that about 100 of the 1000 T-shirts are
below quality standards This is 1 1 __ 3 times the actual
count of 75
Copyright copy by Houghton Mifflin Harcourt 72 All rights reserved
MODULE 10
Ready to Go On
1 The population is the customers in the companyrsquos
computer database The sample is biased because
the customers surveyed are more likely to value their
service
2 number of students who speak 3 or more languages
__________________________________________ size of sample
= total number of students ____________________ size of population
18 ____ 270
= x ______ 30330
18 sdot 337 ____
3 ________
270 sdot 337 ____ 3
= x ______ 30330
2022
______ 30330
= x ______ 30330
x = 2022
About 2022 students speak three or more
languages
3 Two of the random numbers 13 and 167 represent
defective MP3 players
simulated defective players
______________________ size of simulation
= defective players
______________ shipment
2 ___ 10
= x _____ 5000
2 middot 500 _______ 10 middot 500
= x _____ 5000
1000
_____ 5000
= x _____ 5000
x = 1000
Based on the sample about 1000 MP3 players are
defective
4 No the sample is too small compared to the size of
the shipment
5 Sample answer You can make predictions about
populations that are too large to survey
Copyright copy by Houghton Mifflin Harcourt 73 All rights reserved
MODULE 11 Analyzing and Comparing Data
Are You Ready
0875
1 8 ⟌ _
7000
_ -6 400
600
_ -560
40
_ -40
0
0875 875
08
2 5 ⟌ _
40
_ -4 0
0
08 80
025
3 4 ⟌ _
100
_ -80
20
_ -20
0
025 25
03
4 10 ⟌ _
30
_ -3 0
0
03 30
5 4 6 7 7 9 11 15 17
7 + 9
_____ 2 = 8
Median = 8
Mode = 7
6 36 37 40 43 44 49 50 51 56
Median = 44
Mode none
7 9 + 16 + 13 + 14 + 10 + 16 + 17 + 9
________________________________ 8
= 13
Mean = 13
8 108 + 95 + 104 + 96 + 97 + 106 + 94
________________________________ 7 = 100
Mean = 100
LESSON 111
Your Turn
2 Shape dot plots for field hockey players and
softball players have a similar spread
Center center of the field hockey dot plot is less
than the center for softball or basketball players
Spread dot plots for field hockey players and softball
players have a similar spread
3 The median is the middle value Listing the values
in order
1 4 4 4 5 5 5 6 6 6 6 7 7 8 11
In this case median 6 h
range 10 h
The median for internet usage is greater than the
median for exercise and the range is less than the
range for exercise
Guided Practice
1 Class A clustered around two areas
Class B clustered in the middle The dot plots
appear to have about half of the data clustered in
one area
2 Class A two peaks at 4 and 13 mi
Class B looks centered around 7 mi
3 Class A spread from 4 to 14 mi a wide gap with
no data
Class B spread from 3 to 9 mi
4 Class A
4 4 4 4 4 5 5 5 6 6 12 13 13 13 13 14 14
median 6
Class B
3 4 4 4 5 5 5 5 6 6 7 7 7 7 7 8 8 9
median 6
The median for both dot plots is 6 miles
5 Range for class A 14 - 4 = 10 mi
Range for class B 9 - 3 = 6 mi
6 The medians allow you to compare the centers
The ranges allow you to compare the spreads
Independent Practice
7 The dots have a relatively even spread with a peak
at 8 letters
8 The center of the graph is between 6 and 7 letters
9 The dots spread from 3 to 9 letters
10 The mean is the average
3 + 4 + 4 + 5 + 5 + 6 + 7 + 7 + 8 + 8 + 8 + 9
________________________________________ 12
74 ___ 12
asymp 617
Mean asymp 617
3 3 4 5 5 6 7 7 8 8 8 9
Because there are two middle values take their
average
6 + 7
_____ 2 = 13 ___
2 = 65
Median 65
Range 9 - 3 = 6
11 AL clustered in one small interval with an outlier to
the left
VA relatively uniform in height over the same
interval
Copyright copy by Houghton Mifflin Harcourt 74 All rights reserved
12 ALcenteredbetween8and9daysofrainVAcenteredaround10daysofrain
13 ALspreadsfrom1to12daysofrainanoutlierat1VAspreadsfrom8to12daysofrain
14 LynchburgVAhasmoreconsistentlevelsofrainandmorerainpermonthcomparedtoMontgomeryAL
15 GroupAclusteredtotheleftofsize9GroupBclusteredtotherightofsize9
16 OrderedvaluesforgroupA6577757575888888585913Thereare15itemsofdataSince15isoddthereisamiddlenumber8Sothereisnoneedtoaverageanyvalues
MedianforGroupAsize8OrderedvaluesforgroupB859999959595951010105105105115MedianforGroupBsize95
17 GroupArangewithoutlier=13-65=65withoutoutlier=9-65=25GroupBrange=115-85=3
18 SampleanswerGroupAcouldbechildrenandGroupBcouldbeadults
Focus on Higher Order Thinking
19 YesSampleansweronegroupoffivestudentscouldhavethefollowingnumberofpets12345Anothergroupoffivestudentscouldhavethefollowingnumberofpets13335Forbothgroupsofstudentsthemedianwouldbe3andtherangewouldbe4
20RangeanoutliergreatlyincreasestherangewhereasthemedianwillgenerallynotbegreatlyaffectedasitisinthemiddleofallthevaluesAdotplotwillshowboth
LESSON 112
Your Turn
3 SampleanswerTheboxeshavesimilarshapesalthoughGroupBhasashorterboxandshorterwhiskersGroupBrsquosmedianisgreaterthanGroupArsquosGroupBrsquosshorterboxmeansthemiddle50ofitsdataareclosertogetherthanthemiddle50ofGroupArsquos
4 SampleanswerTheshapeissimilartoStoreArsquosThemedianisgreaterthanStoreArsquosandlessthanStoreBrsquosTheinterquartilerangeisaboutthesameasStoreArsquosandlongerthanBrsquos
Guided Practice
1 Minimum72 Maximum88
2 Median79
3 Range88-72=16 IQR85-75=10
4 Themedianheightforhockeyplayersis70inthemedianheightforvolleyballplayersis74Thereforevolleyballplayershavethegreatermedianheight
5 Theminimumheightforhockeyplayersis64intheminimumheightforvolleyballplayersis67inSohockeyplayershavetheshortestplayer
6 IQRforhockeyplayers76-66=10IQRforvolleyballplayers78-68=10BothgroupshaveanIQRof10
7 SampleanswerMinimumandmaximumvaluesmedianrangeandIQRs
Independent Practice
8 CarAhasaminimumof165inandamaximumof210inCarBhasaminimumof160inandamaximumof205inCarAhasamedianof180inCarBhasamedianof185in
9 RangeofCarA210-165=45RangeofCarB205-160=45IQRofCarA195-170=25IQRofCarB200-175=25Bothcarshaverangesof45inandinterquartilerangesof25in
10 CarBhasagreatermediandistancethanCarATheinterquartilerangesarethesamesothemiddle50ofthejumpdistancesforthetwocarshavethesamevariability
11 CarAhaslessvariabilityinthelowestquarterofitsdataandgreatervariabilityinthehighestquarterofitsdataThevariabilityisreversedforCarB
12 CityBhasthelowestpriceof$400andalsohasthehighestpriceof$625
13 MedianforCityA$475MedianforCityB$450Difference475-450=$25CityAhasthehighermedianpriceanditis$25higher
14 SampleanswerCityBabout50ofcarsinCityBleaseforlessthan$450ascomparedtoonly25ofcarsinCityA
15 SampleanswerCityAhasagreatermediancarleasingcostthanCityBCityAhasagreaterIQRofcarleasingcoststhanCityBCityBhasamorepredictablecarleasingcostthanCityAforthemiddle50ofdatavalues
CopyrightcopybyHoughtonMifflinHarcourt 75 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U5M11indd 75 103113 221 AM
Focus on Higher Order Thinking
16 The box plot with the longer box has more variability
in the middle 50 of the values
17 You can identify the minimum and maximum values
and the range of the data You can identify the
quartiles including the lower and upper quartiles
and the median as well as the interquartile range
Together these values help you recognize the
center of the data both the median and the middle
50 It helps you to recognize how spread out the
data are overall and how spread out the middle
50 of the values are around the median A dot
plot contains all the data values which a box plot
does not
18 Sample answer The range tells you very little but
the interquartile range tells you how closely the
middle half of the data cluster around the median
LESSON 113
Your Turn
1 Team 1
Mean
44 + 47 + 67 + 89 + 55 + 76 +85 + 80 + 87 + 69 + 47 + 58 = 804
804 divide 12 = 67
Mean absolute deviation
ǀ 44 - 67 ǀ = 23 ǀ 47 - 67 ǀ = 20
ǀ 67 - 67 ǀ = 0 ǀ 89 - 67 ǀ = 22
ǀ 55 - 67 ǀ = 12 ǀ 76 - 67 ǀ = 9
ǀ 85 - 67 ǀ = 18 ǀ 80 - 67 ǀ = 13
ǀ 87 - 67 ǀ = 20 ǀ 69 - 67 ǀ = 2
ǀ 47 - 67 ǀ = 20 ǀ 58 - 67 ǀ = 11
Mean of absolute values
23 + 20 + 0 + 22 + 12 + 9 +18 + 13 + 20 + 2 + 20 + 11 = 170
170 divide 12 asymp 142
Team 2
Mean
40 + 32 + 52 + 75 + 65 + 70 +72 + 61 + 54 + 43 + 29 + 32 = 625
625 divide 12 asymp 521
Mean absolute deviation
ǀ 40 - 521 ǀ = 121 ǀ 32 - 521 ǀ = 201
ǀ 52 - 521 ǀ = 01 ǀ 75 - 521 ǀ = 229
ǀ 65 - 521 ǀ = 129 ǀ 70 - 521 ǀ = 179
ǀ 72 - 521 ǀ = 199 ǀ 61 - 521 ǀ = 89
ǀ 54 - 521 ǀ = 19 ǀ 43 - 521 ǀ = 91
ǀ 29 - 521 ǀ = 231 ǀ 32 - 521 ǀ = 201
Mean of absolute values
121 + 201 + 01 + 229 +129 + 179 + 199 + 89 +19 + 91 + 231 + 201 = 169
169 divide 12 asymp 141
Difference in means
67 - 521 = 149
149 divide 141 asymp 11
The difference of the means is about 11 times the
MAD
2 There is much more overlap between the two
distributions
Guided Practice
1 Class 1 mean
12 + 1 + 6 + 10 + 1 + 2 + 3 +10 + 3 + 8 + 3 + 9 + 8 + 6 + 8 = 90
90 divide 15 = 6
Class 2 mean
11 + 14 + 11 + 13 + 6 + 7 + 8 + 6 +8 + 13 + 8 + 15 + 13 + 17 + 15 = 165
165 divide 15 = 11
Class 1 mean absolute deviation
ǀ 12 - 6 ǀ = 6 ǀ 1 - 6 ǀ = 5 ǀ 6 - 6 ǀ = 0
ǀ 10 - 6 ǀ = 4 ǀ 1 - 6 ǀ = 5 ǀ 2 minus 6 ǀ = 4
ǀ 3 - 6 ǀ = 3 ǀ 10 - 6 ǀ = 4 ǀ 3 - 6 ǀ = 3
ǀ 8 - 6 ǀ = 2 ǀ 3 - 6 ǀ = 3 ǀ 9 - 6 ǀ = 3
ǀ 8 - 6 ǀ = 2 ǀ 6 - 6 ǀ = 0 ǀ 8 - 6 ǀ = 2
6 + 5 + 0 + 4 + 5 + 4 + 3 + 4 +3 + 2 + 3 + 3 + 2 + 0 + 2 = 46
46 divide 15 asymp 3
Class 2 mean absolute deviation
ǀ 11 - 11 ǀ = 0 ǀ 14 - 11 ǀ = 3 ǀ 11 - 11 ǀ = 0
ǀ 13 - 11 ǀ = 2 ǀ 6 - 11 ǀ = 5 ǀ 7 - 11 ǀ = 4
ǀ 8 - 11 ǀ = 3 ǀ 6 - 11 ǀ = 5 ǀ 8 - 11 ǀ = 3
ǀ 13 - 11 ǀ = 2 ǀ 8 - 11 ǀ = 3 ǀ 15 - 11 ǀ = 4
ǀ 13 - 11 ǀ = 2 ǀ 17 - 11 ǀ = 6 ǀ 15 - 11 ǀ = 2
0 + 3 + 0 + 2 + 5 + 4 + 3 + 5 +3 + 2 + 3 + 4 + 2 + 6 + 2 = 44
44 divide 15 asymp 3
2 Difference in means
11 minus 6 = 5
5 divide 3 asymp 167
3 Sample answer The variation and overlap in the
distributions make it hard to make any convincing
comparison
4 To see how statistical measures vary among the
different samples
Independent Practice
5 23 + 38 + 39 + 48 + 55 + 56 + 71 +86 + 57 + 53 + 43 + 31 = 600
600 divide 12 = 50
ǀ 23 - 50 ǀ = 27 ǀ 38 - 50 ǀ = 12
ǀ 39 - 50 ǀ = 11 ǀ 48 - 50 ǀ = 2
ǀ 55 - 50 ǀ = 5 ǀ 56 - 50 ǀ = 6
ǀ 71 - 50 ǀ = 21 ǀ 86 - 50 ǀ = 36
ǀ 57 - 50 ǀ = 7 ǀ 53 - 50 ǀ = 3
ǀ 43 - 50 ǀ = 7 ǀ 31 - 50 ǀ = 19
27 + 12 + 11 + 2 + 5 + 6 + 21 +36 + 7 + 3 + 7 + 19 = 156
156 divide 12 = 13
The mean is 50degF and the MAD is 13degF
Copyright copy by Houghton Mifflin Harcourt 76 All rights reserved
6 ǀ 23 - 8 ǀ = 15 ǀ 38 - 23 ǀ = 15
ǀ 39 - 24 ǀ = 15 ǀ 48 - 33 ǀ = 15
ǀ 55 - 40 ǀ = 15 ǀ 56 - 41 ǀ = 15
ǀ 71 - 56 ǀ = 15 ǀ 86 - 71 ǀ = 15
ǀ 57 - 42 ǀ = 15 ǀ 53 - 38 ǀ = 15
ǀ 43 - 28 ǀ = 15 ǀ 31 - 16 ǀ = 15
The difference between each average monthly
temperature for City 1 and the corresponding
temperature for City 2 is 15degF
7 50 - 15 = 35
The mean is 35degF and the MAD is 13degF The
mean for City 2 must be 15degF less than the mean
for City 1 and the MAD must be the same
8 50 - 35 = 15
15 divide 13 asymp 12
The difference in the means as a multiple of the
mean absolute deviations is about 12
9
0 4 8 12 16 20 24 28 32 36 40 44
Medians
School B
School A
0 4 8 12 16 20 24 28 32 36 40 44
Means
School B
School A
Both distributions show longer travel times for school
A The distributions of the medians show less
overlap so it is more convincing
10 State A 48 - 38 = 10
10 divide 6 asymp 17
State B 50 - 42 = 8
8 divide 4 = 2
Sample answer The difference in ages is more
significant for State A if you look at the difference in
mean ages but the difference in mean ages is more
significant in State B if you consider variability as
well
11 Smiths Range 70 - 64 = 6
Median 665
Thompsons Range 80 - 74 = 6
Median 77
77 - 665 = 105
105 divide 6 = 175
The difference in the medians is 175 times the
ranges
Focus on Higher Order Thinking
12 Sample answer Jill can reasonably expect the
median of the medians of the samples to be 35
The median of the medians should be close to the
median of the population which should be 35
The outcomes are equally likely
13 Sample answer Ramonrsquos results should produce
more reliable inferences The larger the sample
size the less variability there should be in the
distributions of the medians and means
14 Sample answer Sethrsquos statement is incorrect for any
situation in which the MADs of the population are
not very similar
MODULE 11
Ready to Go On
1 The mean for the start of the school year is given by
5 + 6 + 6 + 7 + 7 + 7 + 7 + 8 + 8 + 8 + 8 + 9 + 9 + 10
________________________________________________ 14
= 105 ____ 14
= 75 mi
The mean for the end of the school year is given by
6 + 6 + 7 + 7 + 8 + 8 + 8 + 8 + 9 + 9 + 9 + 10 + 10 + 10
__________________________________________________ 14
= 115 ___ 14
asymp 82 mi
In summary Start 75 mi End about 82 mi
2 The median is the middle value
List of ordered values for start of school year
5 6 6 7 7 7 7 8 8 8 8 9 9 10
Because there are two middle values take their
average
7 + 8
_____ 2 = 15 ___
2 = 75
Median 75
List of ordered values for end of school year
6 6 7 7 8 8 8 8 9 9 9 10 10 10
Because there are two middle values we would
generally take their average but since they are both
the same and equal to 8
Median 8
Therefore Start 75 mi End 8 mi
3 Range for start of school year 10 - 5 = 5 mi
Range for end of school year 10 - 6 = 4 mi
Therefore Start 5 mi End 4 mi
4 Median for Airplane A 210 in
Median for Airplane B 204 in
Airplane A has a greater median flight length
5 IQR for Airplane A 225 - 208 = 17 in
IQR for Airplane B 230 - 195 = 35 in
Airplane B has a greater interquartile range
Copyright copy by Houghton Mifflin Harcourt 77 All rights reserved
6 The means for the shade plants
7 + 11 + 11 + 12 + 9 + 12 + 8 + 10
______________________________ 8
= 10
The means for the sun plants
21 + 24 + 19 + 19 + 22 + 23 + 24 + 24
__________________________________ 8 = 22
Range of the shade plants 12 - 7 = 5
Range of the sun plants 24 - 19 = 5
Difference in the means 22 - 10 = 12
12 ___ 5
= 24
The difference in the means is 24 times the ranges
7 Sample answer By graphing real-world data you
can identify similarities and differences in related
groups
Copyright copy by Houghton Mifflin Harcourt 78 All rights reserved
MODULE 12 Experimental Probability
Are You Ready
1 6 ___ 10
= 6 divide 2 ______ 10 divide 2
= 3 __ 5
2 9 ___ 15
= 9 divide 3 ______ 15 divide 3
= 3 __ 5
3 16 ___ 24
= 16 divide 8 ______ 24 divide 8
= 2 __ 3
4 9 ___ 36
= 9 divide 9 ______ 36 divide 9
= 1 __ 4
5 45 ___ 54
= 45 divide 9 ______ 54 divide 9
= 5 __ 6
6 30 ___ 42
= 30 divide 6 ______ 42 divide 6
= 5 __ 7
7 36 ___ 60
= 36 divide 12 _______ 60 divide 12
= 3 __ 5
8 14 ___ 42
= 14 divide 14 _______ 42 divide 14
= 1 __ 3
075
9 4 ⟌ _
300
_ -2 80
20
_ -20
0
075
0875
10 8 ⟌ _
7000
_ -6400
600
_ -560
40
_ -40
0
0875
015
11 20 ⟌ _
300
_ -2 00
100
_ -100
0
015
038
12 50 ⟌ _
1900
_ -15 00
4 00
_ -4 00
0
038
13 67 = 67 ____ 100
= 067
14 31 = 31 ____ 100
= 031
15 7 = 7 ____ 100
= 007
16 146 = 100 + 46
= 100 ____ 100
+ 46 ____ 100
= 1 + 046
= 146
17 013 = 13
18 055 = 55
19 008 = 8
20 116 = 116
LESSON 121
Your Turn
3 Because every other number from 1 through 16 is
even choosing an even number is as likely as not
and the probability is 1 __ 2
4 There are 20 possible outcomes when picking a
marble from the jar There are 10 purple marbles
Therefore the probability of picking a purple marble
is 10 ___ 20
or 1 __ 2
5 There are 6 possible outcomes when rolling a cube
There are 2 numbers greater than 4 that can be
rolled 5 and 6 Therefore the probability of rolling a
number greater than 4 is 2 __ 6 or 1 __
3
Solutions KeyProbability
UNIT
6
Copyright copy by Houghton Mifflin Harcourt 79 All rights reserved
7 P(event) + P(complement) = 1
P(5) + P(not 5) = 1
1 __ 8 + P(not 5) = 1
P(not 5) = 7 __ 8
The probability of picking a marble that is not 5 is 7 __ 8
8 P(event) + P(complement) = 1
P(even) + P(odd) = 1
1 __ 2 + P(odd) = 1
P(odd) = 1 __ 2
The probability of rolling an odd number is 1 __ 2
Guided Practice
1 The cards are numbered 1 2 3 4 5 6 7 8 9 10
You pick a number greater than 0 8
You pick an even number 5
You pick a number that is at least 2 7
You pick a number that is at most 0 1
You pick a number divisible by 3 3
You pick a number divisible by 5 2
You pick a prime number 4
You pick a number less than the
greatest prime number 6
2 There are no green playing cards in a standard
deck so randomly picking a green card is
impossible 0
3 There are as many red cards as black cards in a
standard deck so it is as likely as not 1 __ 2
4 All of the numbers are less than 12 so they are also
less than 15 The probability is certain 1
5 There are only two numbers between 1 and 12 that
are divisible by 5 5 and 10 Therefore the probability
is unlikely close to 0
6 There are 5 possible outcomes when spinning the
spinner There are two even numbers 2 and 4
Therefore the probability of the spinner landing on
an even number is 2 __ 5
7 There are 52 possible outcomes when picking a
card from a standard deck There are 13 cards with
diamonds Therefore the probability of picking a
card with a diamond is 13 ___ 52
= 1 __ 4
8 P(event) + P(complement) = 1
P(5) + P(not 5) = 1
1 __ 6 + P(not 5) = 1
P(not 5) = 5 __ 6
The probability of not rolling 5 is 5 __ 6
9 P(event) + P(complement) = 1
P(blue) + P(not blue) = 1
1 __ 3 + P(not blue) = 1
P(not blue) = 2 __ 3
The probability of not landing on blue is 2 __ 3
10 P(event) + P(complement) = 1
P(4) + P(not 4) = 1
1 __ 5 + P(not 4) = 1
P(not 4) = 4 __ 5
The probability of not landing on 4 is 4 __ 5
11 P(event) + P(complement) = 1
P(queen) + P(not queen) = 1
4 ___ 52
+ P(not queen) = 1
P(not blue) = 48 ___ 52
= 12 ___ 13
The probability of not picking a queen is 12 ___ 13
12 Sample answer pulling a red marble out of a bag
that contains only blue marbles pulling a white
marble out of a bag that contains only white marbles
Independent Practice
13 There are 52 possible outcomes when picking from
a standard deck of cards There are 8 cards that
have an ace or a king Therefore the probability of
selecting
an ace or a king is 8 ___ 52
or 2 ___ 13
14 P(event) + P(complement) = 1
P(apple or peach) + P(not apple or peach) = 1
9 ___ 12
+ P(not apple or peach) = 1
P(not apple or peach) = 3 ___ 12
or 1 __ 4
Therefore the probability of picking a piece of fruit
that is not an apple or a peach is 3 ___ 12
or 1 __ 4
15 No it is unlikely that she will have oatmeal for
breakfast Since there are 4 choices the probability
that she will choose oatmeal is 1 __ 4 or 25
16 Purple There are a lot more plants with purple
flowers than with white flowers The probability of
selecting a white-flowered plant is 2 __ 9 while the
probability of selecting a purple-flowered plant is 7 __ 9
17 Because she has more colored T-shirts than white
T-shirts it is likely that she will pick a colored T-shirt
She has 14 total T-shirts and 10 of the shirts are
colored Therefore the probability she will choose a
colored T-shirt is 10 ___ 14
or 5 __ 7
18 1 None of the students in the class have red hair so
it is certain that a randomly chosen student will not
have red hair
Copyright copy by Houghton Mifflin Harcourt 80 All rights reserved
19 a There are 14 total coins and 8 blue coins so the
probability that the coin is blue is 8 ___ 14
or 4 __ 7
b Removing 1 of the 8 blue coins leaves 7 blue
coins Adding 3 more to the 6 red coins makes
9 red coins The total of coins in the bag is now
16 Therefore the probability of choosing a red
coin is 9 ___ 16
c Removing 1 of the 6 red coins leaves 5 red coins
Adding 3 to the 8 blue coins makes 11 blue coins
The total of coins in the bag is now 16 Therefore
the probability of choosing a red coin is 5 ___ 16
Focus on Higher Order Thinking
20 Sample answer If some marbles in a jar are heavier
than others then the heavier marbles would sink
and be less likely to be selected
21 Yes Because there are only two colors selecting
not black is equal to selecting red So
P(not black) + P(black) =P(not black) + P(not red) = 1
22 2 is the number of ways the event can happen 7 is
the number of outcomes in the sample space
landing on blue
LESSON 122
Your Turn
7 The total number of spins is 6 + 14 + 10 = 30
Red 10 ___ 30
= 1 __ 3
Yellow 14 ___ 30
= 7 ___ 15
Blue 6 ___ 30
= 1 __ 5
8 Sample answer Let 1 and 2 represent blue 3 and 4
represent white and 5 and 6 represent blue Toss
the cube 50 times to determine the experimental
probability for each color Predict the next ball will be
the color with the greatest experimental probability
Guided Practice
1 The total number of spins is 14 + 7 + 11 + 8 = 40
A 14 ___ 40
= 7 ___ 20
= 035 = 35
B 7 ___ 40
= 0175 = 175
C 11 ___ 40
= 0275 = 275
D 8 ___ 40
= 1 __ 5 = 020 = 20
2 Sample answer Write ldquoyesrdquo on 6 cards and ldquonordquo on
4 cards Draw a card at random 50 times Use the
number of ldquoyesrdquo cards drawn as the prediction
3 Use an experiment to find the number of times the
event occurs for a certain number of trials
Independent Practice
4 6 ___ 10
or 3 __ 5 It is reasonable to assume that Dreersquos
past performance is an indicator of her future
performance There is no way to accurately
represent 3 __ 5 on a number cube with 6 faces
5 Sample answer Compare the number of wins to the
total number of trials
number of wins _________________ total number of trials
= 8 ___ 48
= 1 __ 6
6 There are 20 possible outcomes when picking a
name Ryan is 1 person Therefore the probability
he is chosen is 1 ___ 20
and the probability he is not
chosen is 19 ___ 20
P(Ryan) + P(not Ryan) = 1
1 ___ 20
+ P(not Ryan) = 1
P(not Ryan) = 19 ___ 20
7 Yes because it is based on actual data of weather
patterns
8 Joan Mica hit the ball 8 ___ 48
times or about 17 of her
times at bat Meanwhile Joan hit the ball 12 ___ 40
times
or 30 of her times at bat Therefore Joan has the
greater experimental probability and is more likely to
get a hit next time
9 Gabbyrsquos experimental probability of hitting an ace
is 4 ___ 10
or 2 __ 5 Gabby could serve 16 aces in her next
40 serves because 2 __ 5 of 40 is 16
10 The experimental probability her dog wonrsquot want to
go outside is 5 ___ 12
or about 417
P(outside) + P(not outside) = 1
7 ___ 12
+ P(not outside) = 1
P(not outside) = 5 ___ 12
or 417
Focus on Higher Order Thinking
11 She did not add 40 and 60 to find the total number
of trials P(heads) = 40 ____ 100
12 Sample answer coin toss Heads represents male
and tails represents female Toss the coin 50 times
and use the results to make a prediction
13 Sample answer Make an index card to represent
each coin then pick one card at random No since
the coins are different sizes they do not each have
the same probability of getting pulled out of my
Copyright copy by Houghton Mifflin Harcourt 81 All rights reserved
LESSON 123
Your Turn
1 P(coffee + small) = number of coffee + small
_____________________ total number of orders
= 60 ____ 400
= 3 ___ 20
= 15
3 P(goId + 20 in) = number of gold + 20 in
_________________________ total number of necklaces sold
= 12 ___ 75
or 4 ___ 25
Guided Practice
1 P(female + age 22ndash39)
= number of female + age 22ndash39
__________________________ total number of patients
= 50 ____ 400
or 1 __ 8
2 Sample answer There are six possible outcomes
standard with vacuum standard with no vacuum
deluxe with vacuum deluxe with no vacuum
superior with vacuum and superior with no vacuum
Students could write the outcomes on six index
cards and put them in a box Then they can draw a
card 50 times record the results and find the
experimental probability that a customer chooses a
deluxe wash with no vacuum by dividing the
frequency of this compound event by 50 the total
number of trials
3 Find the number of occurrences of the compound
event and divide it by the total number of trials
Independent Practice
4 Divide the number of 2 piece + salad orders 33 by
the total number of orders 330
P = number of 2 piece + salad
______________________ total number of orders
= 33 ____ 330
= 1 ___ 10
5 P = number of red notebooks + 150 pages
_______________________________ total number of notebooks sold
= 60 ____ 400
= 3 ___ 20
6 P(red notebook) = number of red notebooks _____________________ total number of notebooks
= 55 + 60 + 23
____________ 400
= 138 ____ 400
= 69 ____ 200
7 12 the total is the product of 3 page-count choices
and 4 color choices
8 She left out the 53 students that read 150 pages
P(7th grade + 100 pages) = 85 ____ 250
= 17 ___ 50
9 Sample answer 8th grade the results table
suggests 8th grade students are the least likely to
have read 150 pages compared to students in 6th or
7th grade
Focus on Higher Order Thinking
10 Greater heads occurs on about half the occasions
that you roll a 6 so the compound event is half as
likely
11 Sample answer For 2 outcomes he could use even
and odd numbers For 3 outcomes he could use
1 or 2 3 or 4 and 5 or 6 For 6 outcomes he could
use each number once
12 P(male + open toe) = 11 ____ 300
P(male has open toe) = 11 ____ 150
No the first scenario
includes females and the second does not
13 No because coins are fair and the probabilities do
not appear to be equally likely
14 Sample answer On a coin heads = male and
tails = female On a number cube (1 or 2) = 6th
grade (3 or 4) = 7th grade and (5 or 6) = 8th
grade Toss the coin and roll the number cube 50
times each Record the number of outcomes that are
heads and 3 or 4
LESSON 124
Your Turn
1 024 times 550 =132 customers
2 No About 371 of the emails out of 12372 will come
back undelivered because 003 times 12372 asymp 371 The
editorrsquos prediction is too high
3 024 times 350 = 84 customers Yes because 107
customers buying two or more pairs would be more
than only 84 customers
Guided Practice
1 030 times 50 = 15 times
2 015 times 365 asymp 55 days
3 No about 1009 of the candles out of 16824 will be
returned because 006 times 16824 asymp 1009
A prediction of 812 is too low
4 No about 746 toys out of 24850 will be defective
because 003 times 24850 asymp 746 A prediction of 872 is
too high
5 98 ____ 100
= x ___ 40
= 39 ___ 40
or 39 times
No if she were late 6 out of 40 times the rate of
being on time would be only 85 in which case the
light-railrsquos claim of 98 is too high
6 18 ____ 100
= x _____ 5000
= 900 _____ 5000
or 900 students Yes the
collegersquos claim is close to the number actually
accepted
times04
times04
times50
times50
Copyright copy by Houghton Mifflin Harcourt 82 All rights reserved
7 Solve a proportion using the experimental probability
to find an expected number of events to happen
Make a prediction based on the expected number of
events
Independent Practice
8 4 ____ 100
= x ____ 200
= 8 ____ 200
or 8 students More students
moved than expected because 12 is more than 8
9 Yes 6th grade 2 ____ 100
= x ____ 250
= 5 ____ 250
or 5 students
7th grade 4 ____ 100
= x ____ 200
= 8 ____ 200
or 8 students
8th grade 8 ____ 100
= x ____ 150
= 12 ____ 150
or 12 students
Since 5 + 8 + 12 = 25 the values in the table
support his claim of 30 students
10 6 ____ 100
= x ____ 300
= 18 ____ 300
or 18 seats If an airplane is
overbooked with 310 passengers only 291 are
expected to show up since 310 times 94 asymp 291
11 006 times 600 = 36 clients If 40 clients did not pay it
would be slightly more than average
12 080 times 20 = 16 team members The coachrsquos claim is
not accurate because the average number of
students at practice is 144 ____ 8 = 8
13 He set up the fraction incorrectly it should be
1 ___ 30
= x ____ 180
Focus on Higher Order Thinking
14 1 __ 2 of 12 = 6 normal rejection rate
500 times 6 = 30 transactions rejected by a
normal gas pump
15 098 times 15000 = 14700 on-time flights Sample
answer No one week of data could be misleading
and not representative of the yearly on-time prob-
ability (because it ignores bad weather etc)
16 Sample answer No They could expect to get 96
responses with the old letter since
4 ____ 100
= x _____ 2400
= 96 _____ 2400
or 96 letters Therefore the
new letter received fewer responses
MODULE 12
Ready to Go On
1 H1 H2 T1 T2
2 6 ___ 10
= 3 __ 5
3 13 ___ 20
4 3 of the 7 total trials resulted in a sum more than 5
Therefore the experimental probability is 3 __ 7
5 I would predict he would reach first base 24 times
because 3 ___ 10
= x ___ 80
= 24 ___ 80
or 24 times
6 You can use the experimental probability based on
observation or simulation to set up a proportion and
use the proportion to predict a value
times15
times15
times24
times24
times2
times2
times3
times3
times2
times2
times25
times25
times8
times8
Copyright copy by Houghton Mifflin Harcourt 83 All rights reserved
MODULE 13 Theoretical Probability and
Simulations
Are You Ready
075
1 4 ⟌ _
300
_ -2 80
20
_ -20
0
075 = 75
04
2 5 ⟌ _
20
_ -2 0
0
04 = 40
09
3 10 ⟌ _
90
_ -9 0
0
09 = 90
035
4 20 ⟌ _
700
_ -6 00
1 00
_ -1 00
0
035 = 35
0875
5 8 ⟌ _
7000
_ thinsp-6 400
600
_ -560
40
_ -40
0
0875 = 875
005
6 20 ⟌ _
100
_ -1 00
0
005 = 5
076
7 25 ⟌ _
1900
_ -17 50
1 50
_ -1 50
0
076 = 76
046
8 50 ⟌ _
2300
_ -20 50
3 00
_ -3 00
0
046 = 46
9 1 - 1 __ 5 = 5 __
5 - 1 __
5
= 4 __ 5
10 1 - 2 __ 9 = 9 __
9 - 2 __
9
= 7 __ 9
11 1 - 8 ___ 13
= 13 ___ 13
- 8 ___ 13
= 5 ___ 13
12 1 - 3 ___ 20
= 20 ___ 20
- 3 ___ 20
= 17 ___ 20
13 8 ___ 15
times 5 __ 8 =
18 ___ 315
times 5 1 ___
8 1
= 1 __ 3
14 2 __ 9 times 3 __
4 =
12 __ 39
times 3 1 ___
4 2
= 1 __ 6
15 9 ___ 16
times 12 ___ 13
= 9 ___ 416
times 12 3 _____
13
= 27 ___ 52
16 7 ___ 10
times 5 ___ 28
= 17 ___
210 times 5
1 ____
28 4
= 1 __ 8
LESSON 131
Your Turn
2 The probability of an event is the ratio of the number
of ways the event can occur to the total number of
equally likely outcomes Therefore
P(rolling a 3 or 4) =
number of sides with 3 or 4 ________________________ total number of sides on cube
= 2 __ 6 = 1 __
3
3 The total number of outcomes in the sample space
is the denominator of the formula for theoretical
probability
Copyright copy by Houghton Mifflin Harcourt 84 All rights reserved
Guided Practice
1
Basket A Basket B
Total number of outcomes5 + 3 + 8
= 16
7 + 4 + 9
= 20
Number of red balls 3 4
P(win) =
Number of red balls
_____________________ Total number of outcomes
3 ___
16 4 ___
20 = 1 __
5
2 To compare the two probabilities of 1 __ 5 and 3 ___
16 use
the least common denominator of 80
1 __ 5 = 16 ___
80
3 ___ 16
= 15 ___ 80
Therefore 16 ___ 80
gt 15 ___ 80
so 1 __ 5 gt 3 ___
16
Choosing Basket B gives you a better chance of
winning
3 There are a total of 6 odd sections The total number
of sections (odd and even) is 11
P(odd) = number of odd sections ____________________ total number of sections
= 6 ___ 11
4 There are a total of 5 even sections The total
number of sections (odd and even) is 11
P(even) = number of even sections ____________________ total number of sections
= 5 ___ 11
5 The total number faces on a number cube is 6 and
rolling either a 3 or 4 is equal to 2 possibilities
P(rolling a 3 or 4) = number of sides with 3 or 4 ________________________ total number of sides on cube
= 2 __ 6 = 1 __
3
6 Sample answer No but it might be reasonably
close
7 Divide the number of ways the event can occur
by 20
Independent Practice
8 P(yellow) = number of yellow sections
_____________________ total number of sections
= 2 __ 6
= 1 __ 3 033 or 33
9 P(blue or green) = number of blue or green sections
___________________________ total number of sections
= 8 ___ 12
= 2 __ 3 067 or 67
10 P(cherry) = number of cherry cough drops
_________________________ total number of cough drops
= 4 ___ 14
= 2 __ 7 029 or 29
11 P(black card) = number of black cards __________________ total number of cards
= 26 ___ 52
= 1 __ 2 050 or 50
12 P(lime) = number of limes ________________________ total number of pieces of fruit
= 12 - 5 ______ 12
= 7 ___ 12
058 or 58
13 There are a total of 20 DVDs There are 12 DVDs
that are not comedies (5 science fiction plus
7 adventure)
P(not a comedy)
= number of DVDs which are not comedies _________________________________ total number of DVDs
= 5 + 7 _________
5 + 7 + 8 = 12 ___
20
= 3 __ 5 060 or 60
14 There are a total of 6 faces on a number cube There
are 2 faces (3 and 4) that are greater than 2 and
less than 5 which means 2 possibilities
P(greater than 2 and less than 5)
= number of sides with 3 and 4 ________________________ total number of sides on cube
= 2 __ 6
= 1 __ 3 033 or 33
15 9 represents the ways the event can occur
13 represents the number of equally likely outcomes
16 There are a total 16 coins and there are 6 coins that
are greater than 5 cents Therefore
P(coin worth more than 5 cents)
= number of coins worth more than 5 cents _________________________________ total number of coins
= 6 ___ 16
or 3 __ 8
The event is choosing a dime or a quarter and 6 of
the 16 coins are dimes or quarters
Focus on Higher Order Thinking
17 Sample answer Riley divided the number of petunia
seeds by the number of begonia seeds rather than
the total number of seeds The correct probability is
5 ______ 5 + 15
= 5 ___ 20
= 1 __ 4
times16
times16
times5
times5
Copyright copy by Houghton Mifflin Harcourt 85 All rights reserved
18 a The total number of students in the club is 35
There are 20 seventh graders Therefore
P(seventh grader) =
number of seventh graders
______________________ total number of students
= 20 ___ 35
= 4 __ 7
There are 15 eighth graders in the club Therefore
P(eighth grader) =
number of eighth graders
_____________________ total number of students
= 15 ___ 35
= 3 __ 7
Because 4 __ 7 gt 3 __
7 choosing a seventh grader is
more likely
b No each student has the same probability of
being selected 1 ___ 35
19 Sample answer The number of trials is twice the
number of marbles in the jar If the probabilities for
each color were the same the number of times that
color was drawn would be twice the number of
marbles with that color in the jar
20 Red The theoretical probability of choosing red is
P(red) = number of red marbles ___________________ total number of marbles
= 8 ___ 20
The experimental probability of choosing red is
14 ___ 40
or 7 ___ 20
Therefore the difference in the theoretical probability
and experimental probability of choosing a red
marble is 8 ___ 20
- 7 ___ 20
= 1 ___ 20
For blue the theoretical probability is
P(blue) = number of blue marbles ____________________ total number of marbles
= 10 ___ 20
The experimental probability is 16 ___ 40
= 8 ___ 20
Therefore the difference in the theoretical probability
and experimental probability of choosing a blue
marble is 10 ___ 20
- 8 ___ 20
= 2 ___ 20
= 1 ___ 10
For yellow the theoretical probability is
P(yellow) = number of yellow marbles
_____________________ total number of marbles
= 2 ___ 20
The experimental probability is 10 ___ 40
= 5 ___ 20
Therefore the difference in the theoretical probability
and experimental probability of choosing a yellow
marble is 5 ___ 20
- 2 ___ 20
= 3 ___ 20
Choosing a red marble has the smallest difference
between theoretical and experimental probability
LESSON 132
Your Turn
3 P(ham sandwich) =
number of combinations containing ham
_________________________________ total number of sandwich combinations
= 4 ___ 12
= 1 __ 3
4 P(sandwich containing Swiss cheese) =
number of combinations containing Swiss
__________________________________ total number of sandwich combinations
= 6 ___ 12
= 1 __ 2
5 To find the sample space make lists of possible
codes First make a list of codes that start with 0
and have 0 as the second digit
0 0 0 0
0 0 0 1
0 0 1 0
0 0 1 1
List of codes that start with 0 and have 1 as the
second digit
0 1 0 0
0 1 0 1
0 1 1 0
0 1 1 1
List of codes that start with 1 and have 0 as the
second digit
1 0 0 0
1 0 0 1
1 0 1 0
1 0 1 1
List of codes that start with 1 and have 1 as the
second digit
1 1 0 0
1 1 0 1
1 1 1 0
1 1 1 1
In total the number of possible outcomes is 16
There are six codes with exactly two 0s
0 0 1 1
0 1 0 1
0 1 1 0
1 0 0 1
1 0 1 0
1 1 0 0
This means the number of outcomes for a code with
exactly two 0s is 6 Therefore
P(Code exactly two 0s)
= number of favorable outcomes ____________________________ total number of possible outcomes
= 6 ___ 16
= 3 __ 8
Copyright copy by Houghton Mifflin Harcourt 86 All rights reserved
Guided Practice
1
1 2 3 4 5 6
11 sdot 1
= 1
1 sdot 2
= 2
1 sdot 3
= 3
1 sdot 4
= 4
1 sdot 5
= 5
1 sdot 6
= 6
22 sdot 1
= 2
2 sdot 2
= 4
2 sdot 3
= 6
2 sdot 4
= 8
2 sdot 5
= 10
2 sdot 6
= 12
33 sdot 1
= 3
3 sdot 2
= 6
3 sdot 3
= 9
3 sdot 4
= 12
3 sdot 5
= 15
3 sdot 6
= 18
44 sdot 1
= 4
4 sdot 2
= 8
4 sdot 3
= 12
4 sdot 4
= 16
4 sdot 5
= 20
4 sdot 6
= 24
55 sdot 1
= 5
5 sdot 2
= 10
5 sdot 3
= 15
5 sdot 4
= 20
5 sdot 5
= 25
5 sdot 6
= 30
66 sdot 1
= 6
6 sdot 2
= 12
6 sdot 3
= 18
6 sdot 4
= 24
6 sdot 5
= 30
6 sdot 6
= 36
2 There are 15 entries in the table that are multiples
of 4 The total number of entries in the table is 36
P(multiple of 4) = number of multiples of 4
_________________________ total number of entries in table
= 15 ___ 36
3 There are 23 entries in the table that are less than
13 The total number of entries is 36
P(less than 13) = number of entries less than 13 _________________________ total number of entries in table
= 23 ___ 36
4 H
HHH HHT
H
H
Coin 1
List
Coin 2
Coin 3 T
T
HTH HTT
H T
T
H
H T
THH THT
T
H T
TTH TTT
Coin 1
List
Coin 2
Coin 3
5 Count the total number of outcomes in the list 8
6 The only way to get three tails is TTT
7 P = number of outcomes with 3 tails __________________________ total number of outcomes
= 1 __ 8
8 There are 3 way(s) to obtain exactly two heads
HHT HTH THH
P = number of outcomes with exactly 2 heads
__________________________________ total number of possible outcomes
= 3 __ 8
9 You need to know the number of equally likely
outcomes in the sample space
Independent Practice
10
Checkered
Red
Checkered
Red
Blue
Black
Checkered
Red
Checkered
Red
Blue
Black
Checkered
Red
Checkered
Red
Blue
Black
Shirt Pants Shoes
Yellow
Red
Green
11 There are 6 combinations that include red shoes
The total number of combinations is 12 Therefore
P(red shoes) = number of combinations with red shoes ________________________________ total number of combinations
= 6 ___ 12
= 1 __ 2
12 There are four combinations that do not include red
Shirt Pants Shoes
Green Blue Checkered
Green Black Checkered
Yellow Blue Checkered
Yellow Black Checkered
P(no red) = number of outfits with no red _______________________ total number of outfits
= 4 ___ 12
= 1 __ 3
13 Let the other three band members be A B and C
The list of possible combinations is
Rhee Pamela
Rhee A
Rhee B
Rhee C
Pamela A
Pamela B
Pamela C
A B
A C
B C
There is a total of 10 combinations Of these only 1
has Rhee and Pamela so
P(Rhee and Pamela)
= Rhee and Pamela ________________________ total number of combinations
= 1 ___ 10
Copyright copy by Houghton Mifflin Harcourt 87 All rights reserved
14 The sample space can be found from adding all
possible combinations of the two numbers
1 2 3 4 5 6
11 + 1
= 2
1 + 2
= 3
1 + 3
= 4
1 + 4
= 5
1 + 5
= 6
1 + 6
= 7
22 + 1
= 3
2 + 2
= 4
2 + 3
= 5
2 + 4
= 6
2 + 5
= 7
2 + 6
= 8
33 + 1
= 4
3 + 2
= 5
3 + 3
= 6
3 + 4
= 7
3 + 5
= 8
3 + 6
= 9
44 + 1
= 5
4 + 2
= 6
4 + 3
= 7
4 + 4
= 8
4 + 5
= 9
4 + 6
= 10
55 + 1
= 6
5 + 2
= 7
5 + 3
= 8
5 + 4
= 9
5 + 5
= 10
5 + 6
= 11
66 + 1
= 7
6 + 2
= 8
6 + 3
= 9
6 + 4
= 10
6 + 5
= 11
6 + 6
= 12
There is a total of 36 possible sums Of these there
are 10 less than 6
P(sum is less than 6)
= number of sums less than 6 ____________________________ total number of possible outcomes
= 10 ___ 36
= 5 ___ 18
15 The sample space can be found from a tree
diagram
Khakis
Shorts
Shirt Pants Shoes
Collared Jeans
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Khakis
Shorts
T-shirt Jeans
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Total number of possible outcomes is 18 the
number of combinations which include jeans but
not sneakers is 4 Therefore
P(jeans but not sneakers)
= number of outfits with jeans no sneakers
_________________________________ total number of possible outcomes
= 4 ___ 18
= 2 __ 9
16 For each chair lift there are 6 possible trails So you
can multiply the number of choices of chair lifts (3)
by the number of trails (6)
17 Because there are 3 choices for the first item and
2 for the second there are 3 middot 2 = 6 possible
outcomes
18 There is a total of 30 possible shoe sizes Of these
the number of red shoes size 9 or larger is 7
Therefore
P(red and size 9 or larger) =
number of red shoes size 9 or larger
______________________________ total number of possible outcomes
= 7 ___ 30
Focus on Higher Order Thinking
19 Sondra orders one item from each column There
are 4 main dishes 4 vegetables and two sides so
the sample space is 4 sdot 4 sdot 2 = 32 The possible
outcomes of Sondrarsquos order are shown in the tree
diagram
Carrots
Sweet potato
Pasta
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Carrots
Sweet potato
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Carrots
Sweet potato
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Carrots
Sweet potato
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Salmon
Beef
Pork
Copyright copy by Houghton Mifflin Harcourt 88 All rights reserved
There are 8 total number of outcomes that include
salmon Therefore
Sondra P(salmon) = 8 ___ 32
= 1 __ 4
Gretchen orders a main dish and a vegetable There
are 4 main dishes and 4 vegetables so the sample
space is 4 sdot 4 = 16 The possible outcomes of
Gretchenrsquos order are shown in the tree diagram
Carrots
Sweet potato
PastaPeas
Asparagus
Carrots
Sweet potato
Peas
Asparagus
Carrots
Sweet potato
Peas
Asparagus
Carrots
Sweet potato
Peas
Asparagus
Salmon
Beef
Pork
There are 4 total number of outcomes that include
salmon Therefore
Gretchen (salmon) = 4 ___ 16
= 1 __ 4
Because the probabilities for Sondra and Gretchen
are equal neither has a greater probability of getting
a meal that includes salmon
20 a For possible two-digit codes consider first codes
that begin with 1 12 13 14 15 There are a total
of 4 possible codes This pattern continues for
each of the 5 digits and therefore we have a total
of 4 + 4 + 4 + 4 + 4 = 20 possible two-digit
codes (four codes each that begin with each of
the numbers 1ndash5)
For possible three-digit codes there are 12
possible codes that begin with 1 and so there are
12 possible codes for each of the numbers 1ndash5
making a total of 5 sdot 12 = 60 possible three-digit
codes
We can predict the number of possible five-digit
codes because we know there are 60 possible
three-digit codes and for each of these there are
only two digits that can be added to the end of
each code to make them five-digit codes These
are the digits that were not used in the three-digit
code and they have two possible orders for a
total of 60 sdot 2 = 120 possible five-digit codes
As a concrete example again consider the three-
digit codes that begin with 1 Tacking on the digits
which are not included in these three-digit codes
in both orders we have 12345 12354 12435
12453 12534 12543 13245 13254 13425
13452 13524 13542 14235 14253 14325
14352 14523 14532 15234 15243 15324
15342 15423 15432 If we do the same for the
three-digit codes beginning with 2ndash5 we will find
the 120 possible five-digit codes
b Now that the numbers can repeat for two-digit
codes take the 20 codes from before and add five
more codes (11 22 33 44 55) which makes a
total of 25 two-digit codes
For three-digit codes take the 60 codes from
before and add the 5 codes that have all digits
the same plus codes which have two digits
which are repeats To find these consider first the
codes with the first two digits the same 112 113
114 115 221 223 224 225 331 332 334 335
441 442 443 445 551 552 553 554 There
are 20 possible codes There are also 20 possible
codes with the last two digits the same Finally
consider the codes where the first and last digits
are the same For the repeated digit 1 we have
121 131 141 151 or 4 possible codes For each
of the digits 1ndash5 we have 4 possible codes for a
total of 4 sdot 5 = 20 Therefore the overall total
60 + 5 + 20 + 20 + 2 = 125 three-digit codes
To solve for how many possible 5 digit codes
there are notice a pattern in the codes For
two-digit codes the total possible codes is the
number of possible digits raised to the power
equal to the number of digits in the code or
52 = 25 For three-digit codes the number of
possible digits is the same and the number
of digits in the code is 3 so we have 53 = 125
Following this pattern there are 55 = 3125
possible five-digit codes
c Sample answer The better choice is to have the
digits repeat there are more unique codes with
repeated digits than without so it would be more
difficult for someone to guess a code for a locker
LESSON 133
Your Turn
1 There are 4 numbers less than 5 on a standard
number cube There are 6 possible outcomes so
P(number less than 5) = 4 __ 6 = 2 __
3
The number of events is 250 Therefore
P(number less than 5) times Number of events =
2 __ 3 times 250 = 16666 or about 167 times
Copyright copy by Houghton Mifflin Harcourt 89 All rights reserved
2 Set up a proportion The probability of getting
heads is 1 __ 2
1 __ 2 = x ___
18
1 __ 2 = x ___
18
x = 9
about 9 times
3 There are 17 total marbles and 8 are red Therefore
P(red) = 8 ___ 17
P(not red) = 1 - 8 ___ 17
= 9 ___ 17
It is more likely that he picks a marble that is not red
4 No Sample answer There is a total of 71 bills in the
bag and there are 11 bills worth $6 or more
Therefore
P(bill worth $6 or more) = 11 ___ 71
This is about a 15 probability so it is not likely you
will win enough to pay for your ticket
Guided Practice
1 An equally likely chance means that the probabilities
of being assigned to each crew are the same and
since there are three possibilities each has a
probability of 1 __ 3
Apartment 1 __ 3 Condo 1 __
3 House 1 __
3
The probability of being assigned to house crew is 1 __ 3
Set up and solve a proportion
1 __ 3 = x ___
18
1 __ 3 = x ___
18
x = 6
This means that Bob can expect to be assigned to
the house crew about 6 times out of 18
2 Since half of the ticket holders will receive a prize
this means that 300 divide 2 = 150 people will receive a
prize Because they are equally likely to receive one
of three prizes the probability of winning each of the
prizes is 1 __ 3 so the probability of winning a movie
ticket is 1 __ 3 The number of events is 150 Therefore
P(movie ticket) times Number of events = 1 __ 3 times 150 =
50 or 50 people are predicted to win a movie ticket
3 The total number of students in Mr Jawaranirsquos class
is 28 The probabilities of picking a student at
random with a certain eye color are
P(hazel) = 9 ___ 28
P(brown) = 10 ___ 28
P(blue) = 7 ___ 28
P(green) = 2 ___ 28
The event with the greatest probability is choosing a
person with brown eyes
4 You can find and compare probabilities Or you can
use probability to set up and solve a proportion or
an equation that relates the probability to the
unknown quantity
Independent Practice
5 The total number of marbles in the bag is 9 The
number of white or gray marbles is 3 Therefore
P(white or gray) = 3 __ 9 = 1 __
3
The number of events is 45 The equation to make a
prediction is then
P(white or gray) times Number of events = 1 __ 3 times 45 = 15
You can expect to get 15 white or gray marbles
6 A spinner which has an equal likelihood to land on
green or yellow means that the number of green and
yellow sections must be equal More likely to land on
red means that there must be more red sections
than yellow or green A Sample answer is
Y GRR
R R
RR
7 Because half the deck is red the probability of
drawing a red card is 1 __ 2 Because there are three
face cards for each of four suits there are 3 sdot 4 = 12
face cards and the probability of drawing a face
card is 12 ___ 52
To compare 1 __ 2 and 12 ___
52 use the least
common denominator of 52 so that 1 __ 2 = 26 ___
52 Given
that 12 ___ 52
lt 26 ___ 52
the probability of drawing a red card
is higher than of drawing a face card and it is more
likely that Dawn draws 2 red cards
8 The total number of aces in a deck is 4 Therefore
P(ace) = 4 ___ 52
= 1 ___ 13
The number of events is 39 The equation to make a
prediction is then
P(ace) middot Number of events = 1 ___ 13
times 39 = 3
He is predicted to draw an ace 3 times
9 The total number of red cards is 26 Therefore
P(red card) = 26 ___ 52
= 1 __ 2
The number of events is 1000 The equation to
make a prediction is then
P(red card) sdot Number of events = 1 __ 2 sdot 1000 = 500
The player is predicted to turn over a red card as the
first card 500 times
10 The sample space can be found from adding all
possible combinations of the two numbers
times6
times6
times9
times9
Copyright copy by Houghton Mifflin Harcourt 90 All rights reserved
1 2 3 4 5 6
1 2 3 4 5 6 7
2 3 4 5 6 7 8
3 4 5 6 7 8 9
4 5 6 7 8 9 10
5 6 7 8 9 10 11
6 7 8 9 10 11 12
There is a total of 36 possible sums Of these there
are 5 ways to roll a sum of 8 and 2 ways to roll a
sum of 11 The probabilities are
P(sum of 8) = 5 ___ 36
P(sum of 11) = 2 ___ 36
Because the probability of rolling a sum of 8 is
greater than that of rolling a sum of 11 ( 5 ___ 36
gt 2 ___ 36
) John is more likely to win
11 There are 5 possible numbers greater than 15 so
P(greater than 15) = 5 ___ 20
= 1 __ 4
The number of events is 180 The equation to make
a prediction is then
P(greater than 15) times Number of events =
1 __ 4 times 180 = 45
The chosen number will be greater than 15 for 45
days in the school year
12 The sample space for a standard cube is 36 and
there are 3 combinations that will have a sum of 4
so P(sum of 3) = 3 ___ 36
= 1 ___ 12
The number of events is 36 The equation to make a
prediction is then
P(sum of 3) times Number of events = 1 ___ 12
middot 36 = 3
Eben is predicted to roll a sum of 4 a total of 3 times
13 Sample answer No Every time you flip a coin the
probability of heads is 1 __ 2 but in reality you could flip
a coin many times and have it land heads up every
time
14 Sample answer A bag of marbles contains red and
blue marbles that are different sizes Since it is easy
to feel the difference between the two colors all of
the outcomes are not equally likely You cannot make
a prediction using theoretical probability
Focus on Higher Order Thinking
15 Sample answer What is the theoretical probability
that the coin lands on heads and you pick a marble
that is not green
The probability that the coin lands on heads is 1 __ 2
and the probability that the picked marble is not
green is 3 + 9 _________
3 + 8 + 9 = 12 ___
20 The product of these two
probabilities is 1 __ 2 times 12 ___
20 = 12 ___
40
16 Sample answer It is much more likely that he rolls a
5 or the coin lands on heads
The probability that Horace rolls a 5 and the coin
lands on heads is given by
P(5 and heads) = 1 __ 2 times 1 __
6 = 1 ___
12
In the case where Horace rolls a 5 or the coin lands
on heads the probability is given by
P(5 or heads) = 1 __ 6 + 1 __
2 - 1 __
6 times 1 __
2 = 7 ___
12
17 Yes but only theoretically because in reality nothing
can occur 05 times Sample answer The probability
that a flipped coin lands heads up is 1 __ 2 so in 75 flips
you can expect heads about 75 ___ 2 or 375 times
LESSON 134
Your Turn
1 Sample answer (data and percent will vary)
Trial Numbers generated 3 Males first
1 0 0 1 No
2 0 1 No
3 1 No
4 0 1 No
5 1 No
6 0 0 0 1 Yes
7 0 0 1 No
8 0 1 No
9 1 No
10 0 0 0 0 1 Yes
For these data the experimental probability that the
elephant gives birth to 3 male calves before having a
female calf is 2 ___ 10
or 20
2 Sample Answer (data and percent will vary)
Trial Numbers generated Correct answers
1 1 0 1 1 0 3
2 0 1 0 0 1 2
3 0 0 0 0 1 1
4 0 0 1 1 0 2
5 1 1 1 1 1 5
6 1 0 0 0 0 1
7 1 0 1 1 0 3
8 1 0 1 0 0 2
9 0 1 1 1 1 4
10 0 0 0 0 0 0
The experimental probability that he gets at least 2
questions right is 7 ___ 10
= 70
Copyright copy by Houghton Mifflin Harcourt 91 All rights reserved
Guided Practice
1 Since there is a 30 or 3 ___ 10
chance of drought let
the numbers 1 to 3 represent years with a drought
and the numbers 4 to 10 represent years without
a drought Since we are interested in the next 4
years perform multiple trials generating 4 random
numbers each time
2
Trial Numbers generated Drought years
1 10 3 5 1 2
2 10 4 6 5 0
3 3 2 10 3 3
4 2 10 4 4 1
5 7 3 6 3 2
6 8 4 8 5 0
7 6 2 2 8 2
8 6 5 2 4 1
9 2 2 3 2 4
10 6 3 1 5 2
3 In 8 out of the 10 trials there was a drought in at
least one of the years The experimental probability
of a drought in at least 1 of the next 4 years is
8 ___ 10
= 80
4 Sample answer Generate whole numbers from
1 to 4 Let 1 to 3 represent the event occurring
and 4 represent the event not occurring
Independent Practice
5 There is only 1 trial Trial 6 where it took exactly
4 contestants to get a winner
6 Since 1 out of 10 trials resulted in exactly
4 contestants the probability is 1 ___ 10
= 10
7 The trials for which at least 4 hurricanes struck are
Trials 2 and 7 or 2 out of 10 trials Therefore the
probability is 2 ___ 10
= 20
8 It is fewer than expected based on the simulation
9 It is unlikely but it is not impossible Each of the 3
numbers could be any number from 1 to 10
However there are 10 possible first numbers 10
possible second numbers and 10 possible third
numbers or a total of 1000 possible numbers when
generating three numbers from 1 to 10 The
probability of generating three 10s is 1 _____ 1000
10 Sample answer Use the numbers 1ndash5 where 1 2
and 3 represent packs which contain a player from
Erikarsquos favorite team Generate numbers randomly
and stop when you get a 1 2 or 3
Trial Numbers generated Number of Packs
1 3 1
2 4 2 2
3 2 1
4 1 1
5 2 1
6 4 5 3 2
7 4 2 2
8 4 5 2 1
9 4 4 3 3
10 5 1 2
The average number of packs she needs to buy is
1 + 2 + 1 + 1 + 1 + 2 + 2 + 1 + 3 + 2
_________________________________ 10
= 16 ___ 10
= 1 3 __ 5
packs Since she cannot buy a fraction of a pack
she must buy 2 packs
Focus on Higher Order Thinking
11 Sample answer The probability that she makes a
shot is 375 = 3 __ 8 Use the whole numbers from 1 to
8 with 1ndash3 representing shots she makes and 4ndash8
representing shots she misses For each new trial
generate 10 random numbers Count the number
of times 1 2 or 3 appears in each trial Divide the
number of trials in which she made at least 3 shots
by the total number of trials
12 Sample answer Their simulation was not
appropriate perhaps because they chose an
incorrect model You would expect there to have
been exactly 4 heads on more of the trials and
more variation in the number of heads in general
MODULE 13
Ready to Go On
1 P(red) = number of red marbles ___________________ total number of marbles
= 12 ___________________ 12 + 12 + 15 + 9 + 12
= 12 ___ 60
= 1 __ 5 020 or 20
2 P(diamond or spade)
= number of diamonds and spades
___________________________ total number of cards
= 13 + 13
_______ 52
= 26 ___ 52
= 1 __ 2 050 or 50
3 The most likely color of marble chosen is the most
common color in this case green
Copyright copy by Houghton Mifflin Harcourt 92 All rights reserved
4 In order to find the experimental probability count
the number of trials in which 1 occurs at least once
In this case there are 4 trials that generated a 1
Therefore the experimental probability is 4 ___ 10
or
40
5 Sample answer You can find the theoretical
probability of an event and then use it to make a
prediction by setting up a proportion
Copyright copy by Houghton Mifflin Harcourt 93 All rights reserved
MODULE 1 Adding and Subtracting Integers
Are You Ready
1 an elevator ride down 27 stories -27
2 a $700 profit 700
3 46 degrees below zero -46
4 a gain of 12 yards 12
1 1
5 183
_ + 78
261
261
5 16 17
6 677
_ -288
389
389
1 1
7 1188
_ +902
2090
2090
1 15 14
8 2647
_ -1885
762
762
9
-8-10 -4-6 -2 2 4 6 8 100 10
-8-10 -4-6 -2 2 4 6 8 100 11
-8-10 -4-6 -2 2 4 6 8 100 12
-8-10 -4-6 -2 2 4 6 8 100
LESSON 11
Your Turn
7 -8 + ( -1 ) = -9
8 -3 + ( -7 ) = -10
9 -48 + ( -12 ) = -60
10 -32 + ( -38 ) = -70
11 109 + 191 = 300
12 -40 + ( -105 ) = -145
13 -150 + ( -1500 ) = -1650
14 -200 + ( -800 ) = -1000
Guided Practice
1 a There are 6 counters
b The red counters represent negative numbers
c -5 + ( -1 ) = -6
2 a There are 9 counters
b The red counters represent negative numbers
c -2 + ( -7 ) = -9
3 -5 + ( -2 ) = -7
-8-7-6-5 -2-1 0-4-3 4 -1 + ( -3 ) = -4
-5-4-3-2 1 2 3-1 0 5 -3 + ( -7 ) = -10
-10 -9-8-7 -4-3-2-6-5 6 -4 + ( -1 ) = -5
-5-4-3-2 1 2 3-1 0 7 -2 + ( -2 ) = -4
-5-4-3-2 1 2 3-1 0 8 -6 + ( -8 ) = -14
-16 -12 -4 0-8 9 -5 + ( -4 ) = -9
10 -1 + ( -10 ) = -11
11 -9 + ( -1 ) = -10
12 -90 + ( -20 ) = -110
13 -52 + ( -48 ) = -100
14 5 + ( 198 ) = 203
15 -4 + ( -5 ) + ( -6 ) = -15
16 -50 + ( -175 ) + ( -345 ) = -570
17 Add their absolute values Use the sign of the
integers as the sign of the sum
Solutions KeyThe Number System
UNIT
1
Copyright copy by Houghton Mifflin Harcourt 1 All rights reserved
Independent Practice
18 a
-4
-6
-8
-2
0
2
-5 + (-3)-3 + (-5)
b No -5 + ( -3 ) is -8 and -3 + ( -5 ) is also -8
19 -3 + ( -1 ) + ( -5 ) + ( -2 ) = -11 the golferrsquos total
score is -11
20 -3 + ( -6 ) = -9 the team lost a total of 9 yards
21 -14 + ( -5 ) + ( -12 ) + ( -23 ) = -54 The total
sack yardage was -54
22 a -10 + ( -8 ) = -18
b -6 + ( -2 ) = -8
c -18 lt -8 Jonestown
23 -100 + ( -75 ) + ( -85 ) = -260
Focus on Higher Order Thinking
24 a -25 + ( -45 ) + ( -75 ) = -145 Jan withdrew
$145
b -35 + ( -55 ) + ( -65 ) = -155 Julie withdrew
$155
c Sample answer $45 $55 and $65
25 It is easier to add -80 + ( -20 ) fi rst to get -100
and then add -173 to get -273
26 Disagree there are three pairs of positive integers
1 and 7 2 and 6 and 3 and 5 and three pairs of
negative integers -1 and -7 -2 and -6 -3 and
-5 The absolute value of the sum of any of these
six pairs is 8
LESSON 12
Your Turn
7 -51 + 23
ǀ -51 ǀ - ǀ 23 ǀ = 28
-51 + 23 = -28
8 10 + ( -18 )
ǀ -18 ǀ - ǀ 10 ǀ = 8
10 + ( -18 ) = -8
9 13 + ( -13 )
ǀ 13 ǀ - ǀ -13 ǀ = 0
10 25 + ( -26 )
ǀ -26 ǀ - ǀ 25 ǀ = 1
25 + ( -26 ) = -1
Guided Practice
1 9 + ( -3 ) = 6
2 3 4 5 8 9 106 7 2 -2 + 7 = 5
-3-2-1 0 3 4 51 2 3 -15 + 4 = -11
-18 -16 -12 -10-14 4 1 + ( -4 ) = -3
-5-4-3-2 1 2 3-1 0 5 -4 + 5 = 1
6 -6 + 6 = 0
7 2 + ( -5 ) = -3
8 -3 + 7 = 4
9 -8 + 14 = 6
10 7 + ( -5 ) = 2
11 5 + ( -21 ) = -16
12 14 + ( -14 ) = 0
13 0 + ( -5 ) = -5
14 32 + ( -8 ) = 24
15 To fi nd -4 + 2 start at -4 and move 2 units to the
right to -2 To fi nd the sum -4 + ( -2 ) start at -4
and move 2 units to the left to -6
Independent Practice
16 -15 + 71 = 56
17 -53 + 45 = -8
18 -79 + 79 = 0
19 -25 + 50 = 25
20 18 + ( -32 ) = -14
21 5 + ( -100 ) = -95
22 -12 + 8 + 7 = 3
23 -8 + ( -2 ) + 3 = -7
Copyright copy by Houghton Mifflin Harcourt 2 All rights reserved
24 15 + ( -15 ) + 200 = 200
25 -500 + ( -600 ) + 1200 = 100
26 9 + ( -22 ) = -13 the team lost 13 yards
27 -55 + 275 = 220 the teamrsquos profi t was $220
28 -47 + 47 = 0 Alexrsquos new balance is $0
29 Sample answer 10 and -2 and 12 and -4
30 Bart won Bartrsquos score = 123 + ( -180 ) = -57
points Samrsquos score = 185 + ( -255 ) = -70 points
-57 gt -70 so Bart has the greater score
Focus on Higher Order Thinking
31 Start at -4 and move 3 to the right to reach -1
Start at 3 and move 4 to the left to reach -1
The sums are equivalent by the Commutative
Property of Addition
32 The weight is dropped from 4 feet above the surface
Add -12 to represent the distance the weight falls
before it hits the bottom 4 + ( -12 ) = -8 The water
is 8 feet deep
33 Sample answer A model with more positive
counters than negative counters represents a sum of
two integers whose sum is positive
34 The sign of the other integer is positive and its value
is 6 or greater Sample explanation If you start at
-5 on a number line you have to move to the right 6
or more units to get a sum that is positive
LESSON 13
Your Turn
4 -7 - 2 = -7 + ( -2 )
-7 + ( -2 ) = -9
5 -1 - ( -3 ) = -1 + 3
-1 + 3 = 2
6 3 - 5 = 3 + ( -5 )
3 + ( -5 ) = -2
7 -8 - ( -4 ) = -8 + 4
-8 + 4 = -4
Guided Practice
1 5 - 8 = -3 Start with 5 positive counters
Add 3 zero pairs and remove 8 positive counters
3 negative counters are left so the difference is -3
2 -5 - ( -3 ) = -2 Start with 5 negative counters
and remove 3 negative counters 2 negative
counters are left so the difference is -2
3 -4 - 5 = -4 + ( -5 ) = -9
0-1-2-3-4-5-6-7-8-9 4 1 - 4 = 1 + -4 = -3
0 1 2 3 4-1-2-3-4 5 8 - 11 = 8 + ( -11 ) = -3
6 -3 - ( -5 ) = -3 + 5 = 2
7 15 - 21 = 15 + ( -21 ) = -6
8 -17 - 1 = -17 + ( -1 ) = -18
9 0 - ( -5 ) = 0 + 5 = 5
10 1 - ( -18 ) = 1 + 18 = 19
11 15 - 1 = 14
12 -3 - ( -45 ) = -3 + 45 = 42
13 19 - ( -19 ) = 19 + 19 = 38
14 -87 - ( -87 ) = -87 + 87 = 0
15 To subtract an integer add its opposite Sample
example 6 - 8 = 6 + ( -8 ) = -2
Independent Practice
16 To fi nd the change to Theorsquos account subtract the
initial balance -$4 from the fi nal balance $25
25 - ( -4 ) = 25 + 4 = 29
The overall change is $29
17 To fi nd the change in elevation subtract the
beginning elevation of -225 feet from the fi nal
elevation of -127 feet
-127 - ( -225 ) = -127 + 225 = 98
The change in elevation was 98 feet
18 Subtract the low temperature -2degF from the high
temperature 90degF
90 - ( -2 ) = 92
The difference between the high and low
temperatures is 92degF
19 Subtract Cheyennersquos score at the end of her turn
from her score at the start of her turn to fi nd the
change in Cheyennersquos score during her turn
-425 - ( -275 ) = -425 + 275 = -150
The change in Cheyennersquos score is -150 points
20 a Final temperature - initial temperature = change
in temperature
Gas A -8 - ( -21 ) = -8 + 21 = 13
13degC increase
Gas B 12 - ( -12 ) = 12 + 12 = 24
24degC increase
Gas C -15 - ( -19 ) = -15 + 19 = 4
4degC increase
b Negative the fi nal temperatures will be less than
the initial temperature because the gas is cooler
So the difference in temperatures will be negative
21 Diet Chow the catrsquos weight changed by
-8 + ( -18 ) = -26 ounces with Diet Chow and
3 + ( -19 ) = -16 ounces with Kitty Diet
Focus on Higher Order Thinking
22 Sample answer Susanne owed her sister $4 Then
she borrowed $10 more How much does Susanne
owe her sister in all
23 Tom found -11 - 4 instead of -11 - ( -4 ) To
subtract -4 he should add the opposite of -4
-11 + 4 = -7
Copyright copy by Houghton Mifflin Harcourt 3 All rights reserved
24 YouranswerwillbegreaterthantheintegeryoustartedwithbecausewhenyousubtractanegativeintegeryouadditsoppositeapositiveintegerForexample-5-( -3)=-5+3=-2-2gt-5
25 -16-21-26subtract5togetthenextterm
LESSON 14
Your Turn
1 Starts-Descends+Ascends-40-13+18=-53+18 =-3535feetbelowthecaveentrance
3 Usenegativeintegersforcheckamountsanduseapositiveintegerforamountdeposited-35+( -45)+180=-80+180 =100$100increase
4 JimJim-10-18+5-12=-10-18-12+5 =-( 10+18+12)+5 =-40+5 =-35Jimrestedat-35feet(35feetbelowthesurface)Carla0-20+5-18=0+5-20-18 =0+5-( 20+18) =5-38 =-33Carlarestedat-33feet(33feetbelowthesurface)
Guided Practice
1 -15+ 9- 12= -6- 12 =-1818feetbelowsealevel
2 -23+5-7=-18-7 =-25-25degF
3 50-40+87-30=10+87-30 =97-30 =6767points
4 -6+15+15=-6+30 =24
5 9- 4- 17= 9- 21 =-12
6 50-42+10=8+10 =18
7 6+13+7-5=19+2 =21
8 65+43-11=108-11 =97
9 -35-14+45+31=-49+76 =27
10 -12+6-4=-6-4 =-10-34-3+39=-37+39 = 2 -10lt2( -12+6-4)lt( -34-3+39)
11 21-3+8=18+8 =26-14+ 31- 6= 17- 6 =11 26gt11( 21-3+8)gt( -14+31-6)
12 SampleanswerAddandsubtractfromlefttoright-5+12+10-7=7+10-7=17-7=10
Independent Practice
13 a 5-1+6-1=9
b 9isapositivescoresoitisoverpar
c 9overparislessthan15overparYesCameronbeathisbestgolfscore
14 -6+14-11=-33feetunderground
15 TheCommutativePropertydoesnotapplytosubtraction3-6+5=2and3-5+6=4
16 a -350+275+70-50=-55Leersquosfinalscoreis-55points
b 45gt-55Barry
17 a 300to400
b 75+30-12+14-8+18-30=75+18+6-12=8787customersmustleavebetween400and500
18 100-18+22-53=51$51
19 45-17-22+18=24$24
20 Carlarsquosaccountdecreased$49-18+22-53=-49andLetarsquosaccountonlydecreased$21-17-22+18=-21Carlarsquosaccounthadthegreatestdecreaseinvalue
Focus on Higher Order Thinking
21 SampleanswerTimoweshisbrother1dollarHeborrows6moredollarsfromhisbrotherHepayshisbrotherback3dollarsHowmuchdoesTimstillowehisbrother-1-6+3=-4$4
22 Nothetotalamountshecouldpayherparentsis10+12+25=47and50-47=3Soshestillneeds$3
23 SampleanswerInthecaseinwhichthefirstnumberispositivethenthesumoftheabsolutevaluesoftheothertwonumbersmustbegreaterthanthevalueofthefirstnumberSampleexample13-5-10=-2ǀ 5ǀ+ǀ 10ǀ=15whichisgreaterthan13
MODULE 1
Ready to Go On
1 -8+( -6)=-14
2 -4+( -7)=-11
3 -9+( -12)=-21
CopyrightcopybyHoughtonMifflinHarcourt 4 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U1M01indd 4 103113 206 AM
4 5 + ( -2 )
ǀ 5 ǀ - ǀ -2 ǀ = 3
5 + ( -2 ) = 3
5 -8 + 4
ǀ -8 ǀ - ǀ 4 ǀ = 4
-8 + 4 = -4
6 15 + ( -8 )
ǀ 15 ǀ - ǀ -8 ǀ = 7
15 + ( -8 ) = 7
7 2 - 9 = 2 + ( -9 )
2 + ( -9 ) = -7
8 -3 - ( -4 ) = -3 + 4-3 + 4 = 1
9 11 - ( -12 ) = 11 + 12
11 + 12 = 23
10 -15 + 9 - 4 = -6 - 4
= -10
There are 10 fewer people on the bus
11 24 + 8 - 12 - 9 = 24 + 8 - ( 12 + 9 ) = 32 - 21
= 11
There are 11 cards left in the stack
12 Sample answer Tonya owes her sister $10 and
her friend $5 By how much will her savings change
after she pays them
-10 + ( -5 ) = -15 $15 decrease
Copyright copy by Houghton Mifflin Harcourt 5 All rights reserved
MODULE 2 Multiplying and Dividing Integers
Are You Ready
1 9 times 3 = 27
2 7 times 10 = 70
3 9 times 8 = 72
4 15 times 10 = 150
5 6 times 9 = 54
6 10 times 23 = 230
7 9 times 9 = 81
8 10 times 20 = 200
9 54 divide 9 = 6
10 42 divide 6 = 7
11 24 divide 3 = 8
12 64 divide 8 = 8
13 90 divide 10 = 9
14 56 divide 7 = 8
15 81 divide 9 = 9
16 110 divide 11 = 10
17 12 + 8 divide 212 + 4
16
18 15 - ( 4 + 3 ) times 2
15 - 7 times 2
15 - 14
1
19 18 - ( 8 - 5 ) 2
18 - ( 3 ) 2
18 - 9
9
20 6 + 7 times 3 - 5
6 + 21 - 5
27 - 5
22
21 9 + ( 2 2 + 3 ) 2 times 2
9 + ( 4 + 3 ) 2 times 2
9 + ( 7 ) 2 times 2
9 + 49 times 2
9 + 98
107
22 6 + 5 - 4 times 3 divide 2
6 + 5 - 12 divide 2
6 + 5 - 6
11 - 6
5
LESSON 21
Your Turn
4 Since the numbers have opposite signs the product
will be negative
ǀ -3 ǀ times ǀ 5 ǀ = 3 times 5 = 15
-3 ( 5 ) = -15
5 Since the numbers have the same sign the product
will be positive
ǀ -10 ǀ times ǀ -2 ǀ = 10 times 2 = 20
( -10 ) ( -2 ) = 20
6 One of the factors is 0 so the product is 0
0 ( -22 ) = 0
7 Since the numbers have the same sign the product
will be positive
8 ( 4 ) = 32
Guided Practice
1 -1 ( 9 ) = -9
2 14 ( -2 ) = -28
3 ( -9 ) ( -6 ) = 54
4 ( -2 ) ( 50 ) = -100
5 ( -4 ) ( 15 ) = -60
6 -18 ( 0 ) = 0
7 ( -7 ) ( -7 ) = 49
8 -15 ( 9 ) = -135
9 ( 8 ) ( -12 ) = -96
10 -3 ( -100 ) = 300
11 0 ( -153 ) = 0
12 -6 ( 32 ) = -192
13 7 ( -75 ) = -525 -$525
14 Start at zero and move 5 units to the left 3 times
3 ( -5 ) = -15 the team lost 15 yards
15 6 ( -2 ) = -12 -12degF
16 Multiply the absolute values of the integers If both
integers have the same sign the product is positive
If they have different signs the product is negative
Independent Practice
17 No her number line shows the correct result -6
but she modeled 2 ( -3 ) instead of -2 ( 3 )
18 2 ( -3 ) = -6 he went down 6 floors
19 5 ( -4 ) = -20 $20 decrease
20 Adam descended 5 feet a total of 5 times
5 ( -5 ) = -25 Adam is 25 feet below sea level
21 7 ( -6 ) = -42 the cost of the jeans decreased by
$42 over the 7 weeks
22 9 ( -6 ) = -54 -54 ( 2 ) = -108 Casey has $108
less in his savings
23 7 ( -8 ) = -56 7 ( -5 ) = -35
-56 + ( -35 ) = -91 The savings decreased by $91
24 Sample answer Dave plays a video game in which
he loses 20 points every time he misses a goal
He misses 8 goals 8 ( -20 ) = -160 he loses
160 points
Copyright copy by Houghton Mifflin Harcourt 6 All rights reserved
25 a 3 ( 3 ) ( -3 ) = 9 ( -3 ) = -27
b 3 ( -3 ) ( -3 ) = -9 ( -3 ) = 27
c -3 ( -3 ) ( -3 ) = 9 ( -3 ) = -27
d 3 ( 3 ) ( 3 ) ( -3 ) = 9 ( 3 ) ( -3 ) = 27 ( -3 ) = -81
e 3 ( 3 ) ( -3 ) ( -3 ) = 9 ( -3 ) ( -3 ) = -27 ( -3 ) = 81
f 3 ( -3 ) ( -3 ) ( -3 ) = -9 ( -3 ) ( -3 ) = 27 ( -3 ) = -81
g When a product of integers has an odd number of
negative factors like -3 ( -3 ) ( -3 ) = -27 and
3 ( 3 ) ( 3 ) ( -3 ) = -81 the sign of the product is
negative
When a product of integers has an even number
of negative factors like ( 3 ) ( -3 ) ( -3 ) = 27 and
3 ( 3 ) ( -3 ) ( -3 ) = 9 ( -3 ) ( -3 ) = 81 the sign of the
product is positive
Focus on Higher Order Thinking
26 -1 ( 3 ) ( 1 ) 1 ( -3 ) ( 1 ) -1 ( -3 ) ( -1 )
27 Unless one of the factors is 0 whenever the factors
have opposite signs the product will be less than or
equal to both of the two factors
28 The sign of the product is equal to the sign of the
integers The sign of the product of the first two
integers will always be positive Multiplying this
product by the remaining factor will make a positive
product if the factor is positive negative if it is
negative
LESSON 22
Your Turn
2 Since only the dividend is zero the quotient is 0
0 divide ( -6 ) = 0
3 Since the numbers have opposite signs the quotient
will be negative
38 divide ( -19 ) = -2
4 Since the numbers have the same sign the quotient
will be positive
-13 divide ( -1 ) = 13
5 Yolanda received the same number of penalties in
each game -25 divide ( -5 ) = 5 and -35 divide ( -7 ) = 5
Guided Practice
1 -14 ____ 2 = -7
2 21 divide ( -3 ) = -7
3 26 ____ -13
= -2
4 0 divide ( -4 ) = 0
5 -45 ____ -5 = 9
6 -30 divide ( 10 ) = -3
7 -11 ____ -1
= 11
8 -31 divide ( -31 ) = 1
9 0 ___ -7 = 0
10 -121 _____ -11
= 11
11 84 divide ( -7 ) = -12
12 500 ____ -25
= -20
13 -6 divide ( 0 ) = undefined any number divided by 0 is
undefined
14 -63 ____ -21
= 3
15 -40 divide ( 4 ) = -10 $10
16 -22 divide ( 11 ) = -2 2 points
17 -75 divide ( -15 ) = 5 5 targets
18 -99 divide ( -9 ) = 11 11 times
19 In both cases if the signs of the initial numbers are
the same the answer will be positive If the signs are
different the answer will be negative
Independent Practice
20 -24 divide ( 12 ) = -2 $2
21 Elisa made a greater number of withdrawals She
made -140 divide ( -20 ) = 7 withdrawals Francis made
-270 divide ( -45 ) = 6 withdrawals and 7 gt 6
22 a -2 - 10 = -12 the temperature decreased 12degF
b -12 divide ( 12 ) = -1 decreased by 1degF each hour
23 The first part the rate of change for the first part
is -200 ft _______ 10 min
= -20 ftmin and the rate of change for
the second part is -300 ft _______ 20 min
= -15 ftmin
20 ftmin gt 15 ftmin
24 Sample answer A football team lost 50 yards due to
5 penalties If the team lost the same number of
yards for each penalty what was the change in field
position for each penalty
25 Sample answer a = - 20 and b = 5 less than
-20 divide 5 = -4 and -20 times 5 = -100
-100 lt -4
26 True if the integers have the same sign the product
and quotient are positive if they have different signs
negative
27 False division by 0 is undefined for any dividend
Focus on Higher Order Thinking
28 a 100 divide 25 = 4 4 points
b -16 divide ( -4 ) = 4 Fred answered 4 questions
incorrectly
29 a divide ( -3 ) = 8
a = -24
8 divide b = -4
a divide b = -24 divide ( -2 ) = 12
Copyright copy by Houghton Mifflin Harcourt 7 All rights reserved
30 Dividing integers with the same sign results in a
positive number Since the original two integers are
negative the quotient is greater than both of these
integers
LESSON 23
Your Turn
1 Reggie earned 110 points
3 ( -30 ) + 200 = -90 + 200
= 110
2 -6 ( 13 ) - 21 = -78 - 21
= -99
4 ( -12 ) divide 6 + 2 = -2 + 2
= 0
5 -87 divide ( -3 ) -9 = 29 - 9
= 20
6 40 divide ( -5 ) + 30 = -8 + 30
= 22
7 -39 divide 3 -15 = -13 - 15
= -28
8 Amber moved 3 ( -3 ) + 5 = -4 or 4 places back
Will moved 2 ( -4 ) + 3 = -5 or 5 places back Will
moved further back
9 ( -10 ) divide 2 - 2 = -5 - 2 = -7
( -28 ) divide 4 + 1 = -7 + 1 = -6
10 42 divide ( -3 ) + 9 = -14 + 9 = -5
( -36 ) divide 9 - 2 = -4 - 2 = -6
Guided Practice
1 -6 ( -5 ) + 12 = 30 + 12
= 42
2 3 ( -6 ) - 3 = -18 - 3
= -21
3 -2 ( 8 ) + 7 = -16 + 7
= -9
4 4 ( -13 ) + 20 = -52 + 20
= -32
5 -4 ( 0 ) - 4 = 0 - 4
= -4
6 -3 ( -5 ) - 16 = 15 - 16
= -1
7 7 ( -5 ) + 20 = -35 + 20
= -15
15 dollars less
8 7 ( -10 ) + ( -100 ) = -70 + ( -100 )
= -170
170 fewer points
9 6 ( -4 ) + 10 = -24 + 10
= -14
Ned lost 14 points
10 4 ( -12 ) + 10 = -48 + 10
= -38
$38 less
11 -3 ( -2 ) + 3 = 6 + 3
= 9
3 ( -4 ) + 9 = -12 + 9
= -3
9 gt -3
-3 ( -2 ) + 3 gt 3 ( -4 ) + 9
12 -8 ( -2 ) -20 = 16 -20
= -4
3 ( -2 ) + 2 = - 6 + 2
= -4
-4 = -4
-8 ( -2 ) -20 = 3 ( -2 ) + 2
13 -7 ( 5 ) - 9 = -35 - 9
= -44
-3 ( 20 ) + 10 = -60 + 10
= -50
-44 gt -50
-7 ( 5 ) -9 gt -3 ( 20 ) + 10
14 -16 ( 0 ) -3 = 0 -3
= -3
-8 ( -2 ) -3 = 16 -3
= 13
-3 lt 13
-16 ( 0 ) -3 lt -8 ( -2 ) -3
15 A negative number usually represents a debt
payment or loss or a change that is a decrease
such as to a savings account
Independent Practice
16 -12 ( -3 ) + 7 = 36 + 7
= 43
17 -42 divide ( -6 ) + 5 -8 = 7 + 5 -8
= 12 -8
= 4
18 10 ( -60 ) -18 = -600 -18
= -618
19 ( -11 ) ( -7 ) + 5 - 82 = 77 + 5 - 82
= 82 - 82
= 0
20 35 divide ( -7 ) + 6 = -5 + 6
= 1
21 -13 ( -2 ) - 16 - 8 = 26 - 16 - 8
= 10 - 8
= 2
22 a 5 ( 2 ) -12 + 3 = 10 -12 + 3
= -2 + 3
= 1
b -3 ( 2 ) -1 + 6 + 7 = -6 -1 + 6 + 7
= -7 + 6 + 7
= -1 + 7
= 6
c Rose has more points than Lily so Rose won
the game
23 5 ( -4 ) -8 = -20 - 8 = -28
24 -36 divide ( -4 ) + 9 = 9 + 9 = 18
Copyright copy by Houghton Mifflin Harcourt 8 All rights reserved
25 a 4 ( -35 ) -9 = -140 -9
= -149
$149 less
b Yes $200 - $149 = $51 $51 gt $50 so Arleen
has enough money
26 a 2 ( -10 ) + 3 = -20 + 3= -17
b 7 + 2 + ( -7 ) = 2
c Warren since 2 is greater than -17
d Sample answer 2 of clubs 2 of spades
3 of spades king of diamonds 10 of clubs
7 of clubs
Focus on Higher Order Thinking
27 Sample answer Ann bought three shirts for $7 each
and a pair of pants for $10 Her mother gave her
$25 By how much did the amount of money Ann
had change
28 Disagree the quotient of two integers is positive if
the integers have the same sign So the first two
integers could have been negative integers
29 5 feet equals 60 inches so Lisa is holding the rock
60 inches above the waterrsquos surface The rock will
travel 4 times -5 = -20 inches or 20 inches below the
surface in 4 seconds 60 + 20 = 80 inches
MODULE 2
Ready to Go On
1 Since the numbers have opposite signs the product
will be negative
( -2 ) ( 3 ) = -6
2 Since the numbers have the same sign the product
will be positive
( -5 ) ( -7 ) = 35
3 Since the numbers have the opposite signs the
product will be negative
( 8 ) ( -11 ) = -88
4 ( -3 ) ( 2 ) ( -2 ) = ( -6 ) ( -2 ) = 12
5 5 ( -3 ) = -15 -15degC
6 -63 ____ 7 = -9
7 -15 ____ -3
= 5
8 0 ____ -15
= 0
9 96 ____ -12
= -8
10 -24 divide 6 = -4 -4 Ib
11 ( -4 ) ( 5 ) + 8 = -20 + 8
= -12
12 ( -3 ) ( -6 ) -7 = 18 -7
= 11
13 -27 ____ 9 - 11 = -3 - 11
= -14
14 -24 ____ -3
- ( -2 ) = 8 + 2
= 10
15 Sample answer Maurice lost 3 nickels in the laundry
and found 1 dime in the couch By how much did the
amount of money he had change
( -3 ) ( 5 ) + 10 = -15 + 10 = -5 He had $05 less
than before
Copyright copy by Houghton Mifflin Harcourt 9 All rights reserved
MODULE 3 Rational Numbers
Are You Ready
1 9 ___ 14
times 7 __ 6 =
3
2
9 ___ 14
times 7 __ 6 1
2
= 3 __ 4
2 3 __ 5 times 4 __
7 = 12 ___
35
3 11 ___ 8
times 10 ___ 33
= 1
4
11 ___ 8 times 10 ___
33 5
3
= 5 ___ 12
4 4 __ 9 times 3 =
3
4 __ 9 times 3 __
1 1
= 4 __ 3 or 1 1 __
3
5 1 __ 2 divide 1 __
4 = 1 __
2 times 4 __
1
=
1 1 __ 2 times 4 __
1 2
= 2 __ 1 = 2
6 3 __ 8 divide 13 ___
16 = 3 __
8 times 16 ___
13
= 1 3 __ 8 times 16 ___
13 2
= 6 ___ 13
7 2 __ 5 divide 14 ___
15 = 2 __
5 times 15 ___
14
= 1
1 2 __ 5 times 15 ___
14 3
7
= 3 __ 7
8 4 __ 9 divide 16 ___
27 = 4 __
9 times 27 ___
16
= 1
1 4 __ 9 times 27 ___
16 3
4
= 3 __ 4
9 3 __ 5 divide 5 __
6 = 3 __
5 times 6 __
5
= 18 ___ 25
10 1 __ 4 divide 23 ___
24 = 1 __
4 times 24 ___
23
= 1 1 __ 4 times 24 ___
23 6
= 6 ___ 23
11 6 divide 3 __ 5 = 6 __
1 times 5 __
3
= 2
6 __ 1 times 5 __
3 1
= 10 ___ 1 = 10
12 4 __ 5 divide 10 = 4 __
5 times 1 ___
10
= 2
4 __ 5 times 1 ___
10 5
= 2 ___ 25
13 21 - 6 divide 3
21 - 2
19
14 18 + ( 7 - 4 ) times 3
18 + 3 times 3
18 + 9
27
15 5 + ( 8 - 3 ) 2
5 + ( 5 ) 2
5 + 25
30
16 9 + 18 divide 3 + 10
9 + 6 + 10
15 + 10
25
17 60 - ( 3 - 1 ) 4 times 3
60 - ( 2 ) 4 times 3
60 - 16 times 3
60 - 48
12
18 10 - 16 divide 4 times 2 + 6
10 - 4 times 2 + 6
10 - 8 + 6
2 + 6
8
LESSON 31
Your Turn
0 _
571428
4 7 ⟌ _
40000000 Dividing into 40
_ -35
50
_ -49
10
_ -7
30
_ -28
20
_ -14
60
_ -56
40 Second appearance of 40
Because the number 40 repeats during the division
process the answer is a repeating decimal
-0 _
571428 or -0571428571428hellip
Copyright copy by Houghton Mifflin Harcourt 10 All rights reserved
0 _ 3
5 3 ⟌ _
100 Dividing into 10
_ -3
10 Second appearance of 10
Because the number 10 repeats during the division
process the answer is a repeating decimal 0 _ 3 or
0333hellip
045
6 20 ⟌ _
900
_ -8 0
1 00
_ -1 00
0
-045
7 -2 3 __ 4 = -thinsp 4 times 2 + 3
_________ 4 = -11 ____
4
275
4 ⟌ _
1100
_ -8
30
_ -28
20
_ -20
0
-275 terminating
8 7 1 __ 3 =
3 times 7 + 1 _________
3 = 22 ___
3
7 _ 3
3 ⟌ _
2200 Dividing into 10
_ -21
1 0 Second appearance of 10
Because the number 10 repeats during the division
process the answer is a repeating decimal 7 _ 3 or
7333hellip repeating
Guided Practice
06
1 5 ⟌ _
30
_ -3 0
0
06 terminating
089
2 100 ⟌ _
8900
_ -80 0
9 00
_ -9 00
0
-089 terminating
3 Simplify the fraction
4 ___ 12
= 4 times 1 _____ 4 times 3
= 1 __ 3
0 _ 3
3 ⟌ _
100 Dividing into 10
_ -3
10 Second appearance of 10
Because the number 10 repeats during the division
process the answer is a repeating decimal 0 _ 3 or
0333hellip repeating
0 _
25
4 99 ⟌ _
25000 Dividing into 25
_ -19 8
520
_ -495
25 Second appearance of 25
Because the number 25 repeats during the division
process the answer is a repeating decimal 0 _
25 or
02525hellip repeating
0 _ 7
5 9 ⟌ _
700 Dividing into 70
_ -63
70 Second appearance of 70
Because the number 70 repeats during the division
process the answer is a repeating decimal 0 _ 7 or
-0777hellip repeating
036
6 25 ⟌ _
900
_ -7 5
1 50
_ -1 50
0
-036 terminating
004
7 25 ⟌ _
100
_ -1 00
0
004 terminating
01420 _
45
8 176 ⟌ _
250000000
_ -17 6
7 40
_ -7 04
360
_ -352
80
_ -0
800 First appearance of 800
_ -704
960
_ -880
800 Second appearance of 800
Because the number 800 repeats during the
division process the answer is a repeating decimal
-01420 _
45 or -014204545hellip repeating
0012
9 1000 ⟌ _
12000
_ -10 00
2 000
_ -2 000
0
0012 terminating
Copyright copy by Houghton Mifflin Harcourt 11 All rights reserved
10 -11 1 __ 6 = -thinsp 6 times 11 + 1
_________ 6 = -67 ____
6
111 _ 6
6 ⟌ _
67000
_ -6
07
_ -6
1 0
_ -6
40 First appearance of 40
_ -36
40 Second appearance of 40
Because the number 40 repeats during the division
process the answer is a repeating decimal
- 67 ___ 6
-111 _ 6 or -111666hellip
11 2 9 ___ 10
= 10 times 2 + 9
__________ 10
= 29 ___ 10
29
10 ⟌ _
290
_ -20
9 0
_ -9 0
0
29 ___ 10
29
12 -8 23 ____ 100
= - 100 times 8 + 23
____________ 100
= -823 _____ 100
823
100 ⟌ _
82300
_ -800
23 0
_ -20 0
3 00
_ -3 00
0
-823 _____ 100
-823
13 7 3 ___ 15
= 15 times 7 + 3
__________ 15
= 108 ____ 15
72
15 ⟌ _
1080
_ -105
3 0
_ -3 0
0
108 ____ 15
72
14 54 3 ___ 11
= 11 times 54 + 3
__________ 11
= 597 ____ 11
54 _
27
11 ⟌ _
597000
_ -55
47
_ -44
30 First appearance of 30
_ -22
80
_ -77
30 Second appearance of 30
Because the number 30 repeats during the division
process the answer is a repeating decimal
597 ____ 11
54 _
27 or 542727hellip
15 -3 1 ___ 18
= -thinsp 18 times 3 + 1 __________
18 = -55 ____
18
30 _ 5
18 ⟌ _
55000
_ -54
1 0
_ -0
1 00 First appearance of 100
_ -90
100 Second appearance of 100
Because the number 100 repeats during the division
process the answer is a repeating decimal
-55 ____ 18
-30 _ 5 or -30555hellip
16 3 2 __ 3 =
3 times 3 + 2 _________
3 = 11 ___
3
3 _ 6
3 ⟌ _
1100
_ -9
2 0 First appearance of 20
_ -1 8
20 Second appearance of 20
Because the number 20 repeats during the division
process the answer is a repeating decimal
3 _ 6 or 3666hellip lbs of apples
17 -2 7 __ 8 = -
8 times 2 + 7 _________
8 = -23 ____
8
2875
8 ⟌ _
23000
_ -16
7 0
_ -6 4
60
_ -56
40
_ -40
0
-2875 lb
18 Disagree the definition of a rational number is a
number that can be written as the ratio of two
integers with a denominator not equal to zero and
3 ___ 47
is a well-defined ratio of two integers Tom did
not divide long enough to correctly determine that
the quotient is a repeating decimal
Copyright copy by Houghton Mifflin Harcourt 12 All rights reserved
Independent Practice
19 basketball players
_______________ football players
= 5 ___ 11
0 _
45
11 ⟌ _
5000 Dividing into 50
_ -4 4
60
_ -55
50 Second appearance of 50
Because the number 50 repeats during the division
process the answer is a repeating decimal
5 ___ 11
0 _
45 or 04545hellip repeating
20 hockey players
______________ lacrosse players
= 6 ___ 10
06
10 ⟌ _
60
_ -6 0
0
6 ___ 10
06 terminating
21 polo players
_____________ football players
= 4 ___ 11
036
11 ⟌ _
4000 Dividing into 40
_ -3 3
70
_ -66
40 Second appearance of 40
Because the number 40 repeats during the division
process the answer is a repeating decimal
4 ___ 11
0 _
36 or 03636hellip repeating
22 lacrosse players
______________ rugby players
= 10 ___ 15
= 5 times 2 _____ 5 times 3
= 2 __ 3
0 _ 6
3 ⟌ _
200 Dividing into 20
_ -1 8
20 Second appearances of 20
Because the number 20 repeats during the division
process the answer is a repeating decimal
10 ___ 15
0 _ 6 or 0666hellip repeating
23 football players
_____________ soccer players
= 11 ___ 11
= 1
11 ___ 11
1 terminating
24 Agree Sample answer There are 10 players on the
lacrosse team and dividing the number of any other
team by 10 will simply move the decimal point one
digit to the left Therefore the ratio of any team over
the lacrosse team will be a decimal that terminates
one place to the right of the decimal point
25 a -4 7 __ 8 = -thinsp 8 times 4 + 7
_________ 8 = - 39 ___
8
b 4875
8 ⟌ _
39000
_ -32
7 0
_ -6 4
60
_ -56
40
_ -40
0
-4875
c Sample answer 4 7 __ 8 is very close to 5 Therefore
You could estimate that the water level changes
by 5 inches per month The total change in the
water level at the end of the 3-month period
would be approximately -15 inches
26 integer terminating
27 Ben is taller because Benrsquos height of 5 5 ___ 16
is equal
to 85 ___ 16
or 53125 ft while Marcusrsquo height of 5 7 ___ 24
is
equal to 127 ____ 24
or 52916hellip ft
28 The first store has the better deal because they
offer 3 __ 4 or 075 of a bushel for $9 while the second
store offers only 2 __ 3 or 0666hellip of a bushel for $9
Focus on Higher Order Thinking
29 When the number 1 is the denominator in a fraction
its decimal form is simply the numerator In all other
cases concerning numbers 1 to 10 the division
process stops when either the remainder is 0 or
when the digits begin to repeat When the numbers
2 4 5 or 8 are in the denominator the decimal form
of a fraction will terminate When the numbers
3 6 7 or 9 are in the denominator the decimal form
of a fraction will be a repeating decimal
30 Julie made a higher score on her math test since
her math test score of 21 ___ 23
is equal to a repeating
decimal of approximately 0913 while her science
test score of 29 ___ 32
is equal to a terminating decimal of
090625
Sample answer The difference in scores cannot be
determined by simply comparing the numerators of
the two fractions because the denominators are not
the same For Julie to compare her scores she
needs to divide the denominators into their respec-
tive numerators until one of the quotients is found to
be greater than the other
31 No although the digits in the decimal appear to
follow a pattern a repeating decimal must have the
same combination of digits that repeat such as
0121212hellip
Copyright copy by Houghton Mifflin Harcourt 13 All rights reserved
LESSON 32
Your Turn
2
50 1 2 3 4
3 + 1 1 __ 2 = 4 1 __
2
3
0-7 -6 -5 -4 -3 -2 -1
-25 + ( -45 ) = -7
6
0 1 2-5-6-7-8 -4 -3-2-1
-8 + 5 = -3
7
10-1
1 __ 2 + ( - 3 __
4 ) = - 1 __
4
8
3 4 5 6 7 80 1 2-3-2-1
-1 + 7 = 6
9
3 4 50 1 2-5-4 -3-2-1
2 1 __ 2 + ( -2 1 __
2 ) = 0
10
3 4 50 1 2-5-4 -3-2-1
-45 + 45 = 0
11
1-1 0
3 __ 4 + ( - 3 __
4 ) = 0
The overall change is 0 cups
12 -15 + 35 + 2
-15 + 55
55 - 15
4
13 3 1 __ 4 + ( -2 ) + ( -2 1 __
4 )
3 1 __ 4 + ( -4 1 __
4 )
3 1 __ 4 - 4 1 __
4
-1
14 -275 + ( 325 ) + 5
-6 + 5
-1
15 15 + 8 + ( -3 )
23 + 3
20
Guided Practice
1
3 4 50 1 2-5-4 -3-2-1
-3 + ( -15 ) = -45
2
0 54321-5-4-3-2-1
15 + 35 = 5
3
0 105-1 -05
1 __ 4 + 1 __
2 = 3 __
4
4
0 54321-5-4-3-2-1
-1 1 __ 2 + ( -1 1 __
2 ) = -3
5
0 54321-5-4-3-2-1
3 + ( -5 ) = -2
6
0 54321-5-4-3-2-1
-15 + 4 = 25
7 -2150 + 2150 = 0 $0
8 -874 + 874 = 0 $0
9 275 + ( -2 ) + ( -525 )
275 + ( -725 )
- ( 725 - 275 )
-45
10 -3 + 1 1 __ 2 + 2 1 __
2 = -3 + 4 = 1
11 124 + 92 + 1
-124 + 102
- ( 124 - 102 )
-22
12 -12 + 8 +13
-12 + 21
21 - 12
9
13 45 + ( -12 ) + ( -45 )
45 + ( -45 ) + ( -12 )
0 + ( -12 )
-12
14 1 __ 4 + ( - 3 __
4 ) = - ( 3 __
4 - 1 __
4 ) = - 2 __
4 = - 1 __
2
Copyright copy by Houghton Mifflin Harcourt 14 All rights reserved
15 -4 1 __ 2 + 2 = - ( 4 1 __
2 - 2 ) = -2 1 __
2
16 -8 + ( -1 1 __ 8 ) = -9 1 __
8
17 Start at -4 and move 6 units to the right
The sum is 2
Independent Practice
18 The opposite of +19 is -19
19 -$225 + $1500 = $1500 - $225 = $1275
20 -3525 m + ( -85 ) = -4375 m
21 4 3 __ 4 mi + ( -3 1 __
4 mi ) = 1 2 __
4 mi = 1 1 __
2 mi
22 1635 m + ( -05 m ) = 163 m above sea level
23 30 + 15 - 25 = 45 - 25 = 20 pts
24 January
Income - Expenses
$1205 - $129060
- ( $129060 - $1205 ) -$8560
February
Income - Expenses
$1183 - $134544
-($134544 - $1183)
-$16244
Kameh lost $8560 in January and $16244 in
February
25 June
Income - Expenses
$2413 - $210623
$30677
July
Income - Expenses
$2260 - $195850
$30150
August
Income - Expenses
$2183 - $184512
$33788
Kameh gained $30677 in June $30150 in July and
$33788 in August
26 First sum all the values in the Income column Then
sum all the values in the Expenses column Subtract
the total expenses from the total income Finally add
the $250 profit from December (not shown in the
table) to find the total profit or loss of the bakery by
the end of August
Income = $1205 + $1183 + $1664 + $2413
$2260 + $2183 = $10908
Expenses = $129060 + $134544 + $1664 +$210623 + $195850 + $184512
= $1020989
Profit = $10908 - $1020989 + $250
= $94811
27 -2 is the opposite or additive inverse of 2
28 a 7 ( 10 ) + 3 ( -15 ) = 70 - 45 = 25 pts
b 2 ( 10 ) + 8 ( -15 ) = 20 - 120 = -100 pts
c 10 + 10 + 10 + 10 + 10 + ( ndash15 ) + ( ndash15 ) + ( ndash15 ) +
( ndash15 ) + ( ndash15 ) or 5 ( 10 ) + 5 ( ndash15 )
Focus on Higher Order Thinking
29 The sum of two negative rational numbers is always
negative The sum of a negative rational number and
a positive rational number is negative if the absolute
value of the negative number is greater than that of
the positive number
30 Sample answer The student might have subtracted
the absolute values of the numbers
31 Yes 55 and -55 are opposites and -23 and 23
are opposites so the expression [ 55 + ( -23 ) ] +
( -55 + 23 ) can be viewed as the sum of two
opposites which is always 0
LESSON 33
Your Turn
1
-9 -8 -7 -6 -5 -4
-65 - 2 = -85
2
42 30-1 1
1 1 __ 2 - 2 = - 1 __
2
3
-10-9 -8 -7 -6 -5 -4 -3 -2 -1 0
-225 - 55 = -775
6
1 2-1 0
025 - ( -150 ) = 175
7
1-1 0
- 1 __ 2 - ( - 3 __
4 ) = 1 __
4
Guided Practice
1
1312111098765 14 15
5 - ( -8 ) = 13
2
-9 -8 -7 -6 -5 -4 -3
3 1 __ 2 - 4 1 __
2 = -8
Copyright copy by Houghton Mifflin Harcourt 15 All rights reserved
3
-15 -13 -11 -9 -5-7
-7 - 4 = -11
4
-6 -5 -4 -3 -2 -1 0 1
-05 - 35 = -4
5 -14 - 22 = -36
6 -125 - ( -48 )
-125 + 48
- ( 125 - 48 )
-77
7 1 __ 3 - ( - 2 __
3 ) = 1 __
3 + 2 __
3 = 1
8 65 - ( -14 ) = 65 + 14 = 79
9 - 2 __ 9
- ( -3 )
- 2 __ 9
+ 3
3 - 2 __ 9
2 9 __ 9 - 2 __
9
2 7 __ 9
10 24 3 __ 8
- ( -54 1 __ 8 )
24 3 __ 8
+ 54 1 __ 8
78 4 __ 8
78 1 __ 2
11 -1 m + ( 105 m ) = -15 m
15 m below sea level
12 -12 1 __ 2 + ( -5 ) = -17 1 __
2
17 1 __ 2
or 175 yards
13 Change in height = Starting height - ending height
533 ft - ( -10 ft ) = 533 ft + 10 ft = 543 ft
14 -4500 + (-3015) = -7515 $7515
15 Explain that she is supposed to start at positive 4 on
the number line then move 12 places to the left
because she is subtracting a positive number She
will end on the number -8 which is the answer
Independent Practice
16 -126degC - 75degC = -201degC
17 -2565 ft - 165 ft + 1245 ft = -297 ft
The diver is 297 ft below the surface
18 -9500 ft - ( -26000 ft ) = 16500 ft
19 29035 ft - ( -36198 ft ) = 65233 ft
70000 ft - ( -26000 ft ) = 96000 ft
Mars has the greater difference by
96000 ft - ( 65233 ft ) = 30767 ft
20 a -5degF + 78degF - 32degF
b 78degF - 32degF
c -5degF + 78degF - 32degF 78degF - 5degF - 32degF 78degF - 37degF = 41degF 78degF - 32degF = 46degF
21 a -$1258 + ( -$3072 ) = -$4330
b -$4330 + ( -$25 ) = -$6830
c $6830 since -$6830 + $6830 = 0
22 a No 4 times 52 in = 208 in
b 208 in - 20 in = 08 in more needed
23 a 5 ft - 72 ft + 22 ft
b 5 ft - 72 ft + 22 ft
5 ft + 22 ft - 72 ft
72 ft - 72 ft
= 0 ft because he moved the same distance
backward and forward
24 a Yes
$425 + $089 + $1099
= $1613 lt $20
b $20 - $1613 = $387 left over
Focus on Higher Order Thinking
25 The Commutative Property of Addition (CPA) could
be used to simplify the two terms that already have
a common denominator first
- 7 ___ 16
- 1 __ 4 - 5 ___
16 = ( - 7 ___
16 ) + ( - 1 __
4 ) + ( - 5 ___
16 )
( - 7 ___ 16
) + ( - 5 ___ 16
) + ( - 1 __ 4 ) by CPA
( -7 + ( -5 ) __________
16 ) + ( - 1 __
4 )
( -12 ____ 16
) + ( - 1 __ 4 )
( - 4 times 3 _____ 4 times 4
) + ( - 1 __ 4 )
( - 3 __ 4 ) + ( - 1 __
4 )
( -3 + ( -1 ) __________
4 )
( -4 ___ 4 ) = -1
26 Lowest -225degF + ( -12degF ) = -345degFHighest -195degF + ( -12degF ) = -315degF
27 Sample answer Yes because both numbers are
rational numbers each can be written as the ratio of
two integers for example a __ b
and c __ d
Both fractions
could be given a common denominator and then
one could then be subtracted from the other The
result would be a fraction which is a rational number
28 No Sample answer It is possible for the
difference of two negative numbers to be negative
[ -4 - ( -1 ) = -3 ] but it is also possible for the
difference to be positive [ -5 - ( -8 ) = 3 ]
Copyright copy by Houghton Mifflin Harcourt 16 All rights reserved
LESSON 34
Your Turn
1
-8 -7 -6 -5 -2 -1 0-4 -3
2 ( -35 ) = -7
2
-2 -1 0 1 2 3 4-4 -3
-3 ( -125 ) = 375
4 ( - 3 __ 4 ) ( - 4 __
7 ) ( - 2 __
3 ) = -
13 times 41 times 2 __________ 14 times 7 times 31
= - 1 times 1 times 2 _________ 1 times 7 times 1
= - 2 __ 7
5 ( - 2 __ 3 ) ( - 3 __
4 ) ( 4 __
5 ) = 2 times 31 times 41
__________ 13 times 41 times 5
= 2 times 1 times 1 _________ 1 times 1 times 5
= 2 __ 5
6 ( 2 __ 3 ) ( - 9 ___
10 ) ( 5 __
6 ) = -
12 times 93 times 51
____________ 13 times 210 times 63
= - 1 times 31 times 1 __________ 1 times 2 times 31
= - 1 __ 2
Guided Practice
1
-5 -2 -1 0-4 -3
5 ( - 2 __ 3 ) = 5 __
1 times ( - 2 __
3 )
= - 5 times 2 _____ 1 times 3
= - 10 ___ 3
= -3 1 __ 3
2
-1 -05 0-2 -15
3 ( - 1 __ 4 ) = 3 __
1 times - 1 __
4
= - 3 times 1 _____ 1 times 4
= - 3 __ 4
3
0 1 2-2 -1
-3 ( - 4 __ 7 ) = 3 __
1 times 4 __
7
= 3 times 4 _____ 1 times 7
= 12 ___ 7
= 1 5 __ 7
4
-2 -1 0 1 2 3 4-4 -3
- 3 __ 4 ( -4 ) = 3 __
4 times 4 __
1
= 3 times 41
______ 14 times 1
= 3 times 1 _____ 1 times 1
= 3 __ 1
= 3
5 4 ( -3 ) = -12
6 -18 ( 5 ) = -9
7 -2 ( -34 ) = 68
8 054 ( 8 ) = 432
9 -5 ( -12 ) = 6
10 -24 ( 3 ) = -72
11 1 __ 2 times 2 __
3 times 3 __
4 = ( 1 times 21
______ 12 times 3
) ( 3 __ 4 )
= ( 1 __ 3 ) ( 3 __
4 )
= 1
1 __ 3 times 3 __
4 1
= 1 __ 4
12 - 4 __ 7 ( -thinsp 3 __
5 ) ( - 7 __
3 ) = ( - 4 times 3 _____
7 times 5 ) ( - 7 __
3 )
= 12 ___ 35
( - 7 __ 3 )
= - 4
5 12 times 7 ______ 35 times 3
1
1
= - 4 times 1 _____ 5 times 1
= - 4 __ 5
13 ( - 1 __ 8 ) times 5 times 2 __
3 = ( - 1 __
8 ) times 5 __
1 times 2 __
3
= - 1 times 5 times 21
__________ 48 times 1 times 3
= - 1 times 5 times 1 _________ 4 times 1 times 3
= - 5 ___ 12
Copyright copy by Houghton Mifflin Harcourt 17 All rights reserved
14 ( - 2 __ 3
) ( 1 __ 2 ) ( - 6 __
7 ) = 2 times 1 times 62
__________ 13 times 21 times 7
= 1 times 1 times 2 _________ 1 times 1 times 7
= 2 __ 7
15 4 ( -350 ) = -14 or a $14 change in price
16 18 ( -100 ) = -1800 or a $1800 change
17 Sample answer Count the number of times there is
a negative sign If there are an even number of
negative signs then the final product will be positive
If there is an odd number of negative signs then the
final product will be negative
Independent Practice
18 a 6 ( -1998 ) Note that the change in her bank
account balance does not depend on the initial
amount
b 200 + 6 ( -1998 )
= 200 - 11988
= 8012 $8012
19 Sample answer Start at 0 then move 15 units to
the left (because 15 is negative in this case) 4 times
You are now on -6 Then because 4 is negative in
this case we want to move to the opposite of -6
which is 6
20 8 ( -3 1 __ 4 ) = -8 ( 13 ___
4 )
= - 1
8 __ 1 times 13 ___
4 1
= - 2 times 13 ______ 1 times 1
= - 26 ___ 1
-26 min At the same rate the watch will be
26 minutes behind after 8 weeks
21 3 ( -325 ) = -975 ft The change in depth is -975 ft
Therefore the submarine will be 975 below sea level
(below the surface)
22 5 + ( -3 ) ( 15 )
= 5 + ( -45 )
= 05 cups left
23 Matthew is incorrect Sample answer Matthew
should have said that multiplying by two negatives
is like multiplying the opposite of a positive twice
The opposite of a positive twice brings you back to
a positive
24 5 ( -15 ) = -75 min Therefore she will be late by
75 minutes or 1 hour and 15 minutes
25 Total score is
2 times ( 6 ) + 16 times ( 05 )
+ 7 times ( -05 ) + 2 times ( -15 )
= 12 + 8 - 35 - 3
= 20 - 65
= 135 pts
Focus on Higher Order Thinking
26 Temperature at 5 kilometers
= Temp at ground level + change in temp
= 12 + 5 ( -68 )
= 12 + ( -34 )
= -22degC
27 a b c d
+ + + +
+ + - +
+ - + +
- + + +
- - - +
- - + -
- + - -
+ - - -
28 If the product of two numbers is positive then the two
numbers must have the same sign either they are
both positive or both negative If the sum is negative
then at least one of the numbers must be negative
Therefore the two integers that add to -7 and multiply
to 12 must both be negative The negative paired
factors of 12 are -1 and -12 -2 and -6 and -3
and -4 Of those choices only -3 and -4 add to -7
LESSON 35
Your Turn
3 28 ___ -4
= - 28 ___ 4 = -07
4 -664 ______ -04
= 664 ____ 04
= 166
5 - 55 ___ 05
= - 55 ___ 5 = -11
6 -4256 _______ 112
= -38
The divers change in elevation was -38 feet
per minute
7 - 5 __
8 ___
- 6 __ 7 = - 5 __
8 divide - 6 __
7
= - 5 __ 8 times - 7 __
6
= 35 ___ 48
8 - 5 ___
12 ____
2 __ 3 = - 5 ___
12 divide 2 __
3
= - 5 ___ 12
times 3 __ 2
= - 15 ___ 24
= - 5 __ 8
Copyright copy by Houghton Mifflin Harcourt 18 All rights reserved
9 -4__5
___1__2 =-4__5divide1__
2
=-4__5times2__1
=-8__5
=-13__5
Guided Practice
1 072_____-09=-72___
9 =-08
2 -1__5
___7__5 =-1__
15times5
1__
7=-1times1_____
1times7=-1__7
3 56___-7=-56___7=-8
4 251____4 divide(-3__
8)=251____
4 times-8__
3
=-251times82________
14times3
=-251times2_______1times3
=-502____3
5 75____-1__5
=-75___1times5__
1=-75times5______
1times1=-375
6 -91____-13=91___
13=7
7 -3__7
___9__4 =-
13__7times4__93
=-1times4_____7times3
=-4___21
8 - 12____003
=-1200_____
3 =-400
9 =changeinwaterlevel_________________
changeindays
=-35L______4day
=-0875 L____day
or-0875Lperday
10 =totalchangeinprice_________________
changeindays
=-$4575________5day
=-$915perdayonaverage
11 totalchangeinaltitude___________________
numberofminutes
=-044mi________08min
=-44mi______8min
=-055mileperminute
12 FirstfindthesignofthenumeratorwhichisnegativeNextfindthesignofthedenominatorwhichisnegativeThereforethequotientwillbepositivebecausethenumeratoranddenominatorbothhavethesamesign
Independent Practice
13 5___-2__
8=-5__
1times8__
24
1=-5times4_____
1times1=-20
14 51__3divide(-11__
2)
=-3times5+1_________3 divide2times1+1_________
2
=-16___3divide3__
2
=-16___3times2__
3
=-16times2______3times3
=-32___9
15 -120_____-6 =120____
6 =20
16 -4__5
___-2__
3=
24__5times3__
21=2times3_____
5times1=6__
5
17 103divide(-103)=-103____1 times 1____
103
=-103times1________1times103
=-103____103
=-103____103
=-01
18 -04_____80
=-04___80
=-0005
19 1divide9__5=1__
1times5__
9=5__
9
20 -1___4 ___
23___24
=-1__
14times246
___23
=-1times6______1times23
=-6___23
21 -1035_______-23 =1035_____
23 =45
22 totalhours_____________numberofdays
= 21h______7days
=3 h____day
totaltimelost3 h____day
times3days=9hours
Alexusuallyruns21hoursperweeksodivideby7tofindthatheruns3hoursperdaySinceheisunabletorunfor3dayshistimeisdecreasedby9hoursor-9
23 totalchangeinyards
_________________numberofruns
=-4times15+3___________4 times1__
9
yd___run
=-763___4 times1__
91yd
___run
=-153__
4yd______
9runs
=-153__4times1__
9
yd___run
=-7__4or-13__
4yardsperrun
CopyrightcopybyHoughtonMifflinHarcourt 19 Allrightsreserved
DO NOT EDIT--Changes must be made through File info CorrectionKey=B
7_MCABESK207233_U1M03indd 19 103113 759 PM
24 -121degC + ( -78degC ) + ( -143degC ) + ( -72degC )
_____________________________________ 4
= 414degC ______ 4
= -1035degC per day
25 a total profit
_____________ number of days
= $1750
______ 7 days
= $250 per day
b $150
_____ day
times 7 days = $1050
c total change
_____________ number of days
= - $490
______ 7 days
= -$70 per day
26 total meters descended ___________________ number of seconds
= 996 m ______ 12 s
= 83 ms
27 When converting the division equation into a
multiplication problem he forgot to multiply by the
reciprocal and instead multiplied by the fraction in
the denominator The correct answer is given by
- 3 __
4 ___
4 __ 3
= - 3 __
4 times 3 __
4 = - 9 ___
16
28 -37 m _______ year times ( 2012 ndash 1995 ) years
= -37 m _______ year times 17 years
= -629 m
Focus on Higher Order Thinking
29 Sample answer The average change in temperature
per day would be given by -85 divide 15 if the
temperature were to drop of 85degF over 15 days
-85degF divide 15 d
= - 1785 ____ 315
degF __ d
= - 17 ___ 3 degF __
d or -5 2 __
3 degF __
d asymp -567 degF __
d
On average the temperature changed by -567degF
every day
30 Yes By definition the result of dividing an integer by
a non-zero integer is a rational number
31 Yes The result of dividing an integer by a non-zero
integer always results in a rational number by
definition
LESSON 36
Your Turn
1 Find the total commercial time
3 times 2 1 __ 2 = 7 1 __
2
Find the total entertainment time
30 - 7 1 __ 2 = 22 1 __
2
Find the length of each entertainment segment
22 1 __ 2 divide 4 = 5 5 __
8
Each entertainment segment is 5 5 __ 8 minutes long
2 Find the number of cups of sugar in the bag
454 divide 48 asymp 95
Find the number of 3 __ 4 -cup portions in the bag
95 divide 075 asymp 127
12 batches can be made from the bag of sugar
Find the cost of 1 batch
349 divide 12 asymp 029
The cost of the sugar is $029 per batch
3 Convert the percent to a decimal
12 3 __ 5 = 126
= 0126
Find the worth after 1 year
750 times 0126 = 945
750 + 945 = 8445
Find the worth after 2 years
8445 times 0126 asymp 10641
8445 + 10641 = 95091
Find the worth after 3 years
95091 times 0126 asymp 11981
95091 + 11981 = 107072
The stock is worth $107072
Guided Practice
1 45h times 3 1 __ 5 or 32 miles per hour = 144 miles
144 miles divide 3 3 __ 5 or 36 miles per hour = 4 hours
2 2568 inches times -002375 asymp -061 inches
2568 inches - 061 asymp 2507 inches
3 Sample answer Using a calculator to solve a
problem that involves complicated arithmetic can
help you avoid errors It can also help you to check
solutions to any problems you solved by hand
Independent Practice
4 Find the total weight
78 times 3 = 234
Find the weight each climber carries
234 divide 4 = 585
Each climber carries 585 kg
Copyright copy by Houghton Mifflin Harcourt 20 All rights reserved
5 Find the available width on the page
12 - 3 1 __ 2 = 8 1 __
2
Find half the width
8 1 __ 2 divide 2 = 4 1 __
4
He should put the picture 4 1 __ 4 inches from each side
of the page
6 Find the amount of cereal needed for all the children
11 times 1 __ 3 = 3 2 __
3
10 times 3 __ 4 = 7 1 __
2
3 2 __ 3 + 7 1 __
2 = 11 1 __
6
Compare the total needed with the amount in the
box
11 1 __ 6 lt 12
Yes there is enough Oaties for all the children The
amount needed is 11 1 __ 6 cups and that is less than the
amount in the box 12 cups
7 Find half of the distance that the referee walked
41 3 __ 4 divide 2 = 20 7 __
8
Find how far that distance is from the goal line
50 - 20 7 __ 8 = 29 1 __
8
The referee is 29 1 __ 8 feet from the nearest goal line
8 Donovanrsquos score was 39 ___ 50
= 78 Marcirsquos score was
( 78 + 10 ) = 88
9 Find the number Marci answered correctly
88 = 88 ____ 100
= 44 ___ 50
Find how many more that Marci answered than
Donovan
44 - 39 = 5
Marcie answered 5 more questions correctly than
Donovan
10 Sample answer Donovan got about 40 out of 50
questions right or about 80 Since Marci scored
10 more that is about 90 90 times 50 is 45 So
Marci answered about 45 - 40 or 5 more questions
correctly than Donovan
11 Yes -075 is a reasonable estimate
19 ___ 37
is about 1 __ 2 and 143 is about 15 and
15 times ( - 1 __ 2 ) = -075
12 Sample answer approximately -07343 Use a
calculator Divide -19 by 37 multiply the quotient by
143 then round the product
13 Sample answer Yes -07343 asymp - 075
Focus on Higher Order Thinking
14 Find the time of the descent
-79 9 ___ 10
divide ( -188 ) = 425
Find the time for the ascent
19 1 __ 8 - 1275 - 425 = 2 1 __
8
Find the distance of the ascent
-28 9 ___ 10
- ( -79 9 ___ 10
) = 51
Find the rate of the ascent
51 divide 2 1 __ 8 = 24
The diverrsquos rate of change in elevation during the
ascent was 24 ftmin
15 Sample answer
(1) Convert the mixed number 27 3 __ 5 to the decimal
276 find the sum of 276 and 159 then multiply
the result by 037
(2) Convert the mixed number 27 3 __ 5 to the decimal
276 Then use the Distributive Property so that
(276 + 159)037 = (276)(037) + (159)(037)
Multiply both 276 and 159 by 037 and add the
products I would use the first method because
there are fewer steps and so fewer chances to
make errors
16 Sample answer You need to know how many
gallons of paint you need to paint a wall Measure
the length and width of the wall with a yardstick
then find the area Use the calculator to divide the
area by the number of square feet a gallon of the
paint covers Round up rather than down to the
nearest gallon so you have enough paint
MODULE 3
Ready to Go On
1 4 1 __ 5 =
5 times 4 + 1 _________
5 = 21 ___
5
42
5 ⟌ _
210
_ -20
1 0
_ -1 0
0
42
Copyright copy by Houghton Mifflin Harcourt 21 All rights reserved
2 12 14 ___ 15
= 15 times 12 + 14
___________ 15
= 194 ____ 15
129 _ 3
15 ⟌ _
194000
_ -15
44
_ -30
14 0
_ -13 5
50 first 50
_ -45
50 second 50
Because the number 50 repeats during the division
process the answer is a repeating decimal
129 _ 3 or 12933
3 5 5 ___ 32
= 32 times 5 + 5
__________ 32
= 165 ____ 32
515625
32 ⟌ _
16500000
_ -160
5 0
_ -3 2
1 80
_ -1 60
200
_ -192
80
_ -64
160
_ -160
0
515625
4 45 + 71 = 116
5 5 1 __ 6 + ( -3 5 __
6 ) = 4
6+1 ____
6 -3 5 __
6
= 1 2 __ 6
= 1 1 __ 3
6 - 1 __ 8 -6 7 __
8 = - 1 __
8 + ( -6 7 __
8 )
= -6 8 __ 8
= -7
7 142 - ( -49 ) = 142 + 49
= 191
8 -4 ( 7 ___ 10
) = - 4 __ 1 times 7 ___
10
= - 24 times 7 _______ 1 times 105
= - 2 times 7 _____ 1 times 5
= - 14 ___ 5 or -2 4 __
5
9 -32 ( -56 ) ( 4 ) = 32 times 56 times 4
= 7168
10 - 19 ___ 2 divide 38 ___
7 = -
119 times 7 _______ 2 times 382
= - 1 times 7 _____ 2 times 2
= - 7 __ 4
11 -3201 _______ -33
= 3201 _____ 33
97
33 ⟌ _
3201
_ -297
23 1
_ -23 1
0
97
12 Add the initial stock price with the increase from the
second day
$8360 + $1535 = $9895
Convert the percent decrease to a decimal
-4 3 __ 4 = -475 or -00475
Multiply the price on the second day times the
percent decrease and then subtract the result from
the price on the second day to find the final stock
price
$9895 times -00475 asymp -$47
$9895 - $47 = $9425
The final stock price is $9425 Yes this is
reasonable price on day 1 asymp $85 price on day
2 asymp $100 So the price on day 3 asymp $95
13 Sample answer You can use negative numbers to
represent temperatures below zero or decreases in
prices
Copyright copy by Houghton Mifflin Harcourt 22 All rights reserved
MODULE 4 Ratios and Proportionality
Are You Ready
1 3 __ 4 divide 4 __
5 = 3 __
4 times 5 __
4
= 15 ___ 16
2 5 __ 9 divide 10 ___
11 = 5 __
9 times 11 ___
10
= 1
5 __ 9 times 11 ___
10 2
= 11 ___ 18
3 3 __ 8 divide 1 __
2 = 3 __
8 times 2 __
1
= 4
3 __ 8 times 2 __
1 1
= 3 __ 4
4 16 ___ 21
divide 8 __ 9 = 16 ___
21 times 9 __
8
=thinsp 2
7 16 ___ 21
times 9 __ 8 3
1
= 6 __ 7
5 B ( -4 1 )
6 C ( 3 0 )
7 D ( 5 4 )
8 E ( -2 -2 )
9 F ( 0 0 )
10 G ( 0 -4 )
LESSON 41
Your Turn
3 1 __ 6 acre divide ( 1 __
4 hour ) = 1 __
6 times 4 __
1
= 3
1 times 4 _____ 6 times 1
2
= 1 times 2 _____ 3 times 1
= 2 __ 3 acre per hour
4 3 cups divide ( 3 __ 4 cups ) = 3 __
1 divide 3 __
4
= 3 __ 1 times 4 __
3
= 1
3 times 4 _____ 1 times 3
1
= 1 times 4 _____ 1 times 1
= 4 cups
5 Jaylan 3 __ 4 divide 1 __
5 = 3 __
4 times 5 __
1 = 15 ___
4 = 3 3 __
4
Wanchen 2 __ 3 divide 1 __
6 = 2 ___
1 3 times 6
2 __
1 = 4 __
1 = 4
Jaylanrsquos unit rate is 3 3 __ 4 cups of water per cup of lime
juice Wanchenrsquos unit rate is 4 cups of water per cup
of lime juice Wanchenrsquos limeade has a weaker lime
flavor because 4 gt 3 3 __ 4 and the limeade with a
greater ratio of water to lime juice will have a weaker
flavor
Guided Practice
1
Distance (mi) 8 1 __ 2 17 25 1 __
2 34 42 1 __
2
Time (h) 1 __ 2 1 1 1 __
2 2 2 1 __
2
2 3 1 __ 2 miles divide ( 1 1 __
4 hours ) = 7 __
2 divide 5 __
4 mi ___ h
= 7 times 4 _____ 2 times 5
= 1 7 times 4 _____ 2 times 5
2
= 7 times 2 _____ 1 times 5
= 14 ___ 5 mi ___
h
= 2 4 __ 5 miles per hour
3 5 __ 8 page divide ( 2 __
3 minute ) = 5 __
8 times 3 __
2
= 15 ___ 16
page per minute
4 1 __ 6 foot divide ( 1 __
3 hour ) = 1 __
6 times 3 __
1
= 2 1 times 3 _____ 6 times 1
1
= 1 times 1 _____ 2 times 1
= 1 __ 2 foot per hour
5 5 __ 8 sq ft divide ( 1 __
4 hour ) = 5 __
8 times 4 __
1
= 2 5 times 4 _____ 8 times 1
1
= 5 times 1 _____ 2 times 1
= 5 __ 2 or 2 1 __
2 square feet per hour
Solutions KeyRatios and Proportional Relationships
UNIT
2
Copyright copy by Houghton Mifflin Harcourt 23 All rights reserved
6 240 milligrams divide ( 1 __ 3 pickle ) = 240 ____
1 divide 1 __
3
= 240 ____ 1 times 3 __
1
= 720 ____ 1
Brand Arsquos rate is 720 mg per pickle
325 milligrams divide ( 1 __ 2 pickle ) = 325 ____
1 divide 1 __
2
= 325 ____ 1 times 2 __
1
= 650 ____ 1
Brand Brsquos rate is 650 milligrams per pickle and is
therefore lower than Brand A
7 The unit rate for Ingredient C is
1 __ 4 cup divide ( 2 __
3 serving ) = 1 __
4 times 3 __
2
= 3 __ 8
cup _______
serving
The unit rate for Ingredient D is
1 __ 3 cup divide ( 3 __
4 serving ) = 1 __
3 times 4 __
3
= 4 __ 9
cup _______
serving
To compare 3 __ 8 to 4 __
9 find the least common
denominator of 8 and 9 so that 3 __ 8 = 27 ___
72 and 4 __
9 = 32 ___
72
Therefore ingredient Crsquos unit rate is lower
8 Divide the number in the numerator by the number
in the denominator Write the result with the units of
the rate
For example 1 mile ______
1 __ 2 hour
= 1 __
1 __ 2 = 2 miles per hour
Independent Practice
9 a The unit rate in dollars per hour for On Call is
$10 divide ( 35 hours ) = 10 ___ 35
$ __
h asymp $286 per hour
The unit rate in dollars per hour for Talk Time is
$125 divide ( 1 __ 2 hours ) = 125 ____
05 $ __
h asymp $250 per hour
b Talk Time offers the better deal because its rate in
dollars per hour is lower
c To convert dollars per minute to dollars per hour
multiply by 60
$005 divide ( 1 minute )
= 005 ____ 1
$ ____
min times 60 min ______
1 h
= $3 per hour
d $3 per hour is more expensive than either On Call
or Talk Time so it is not a better deal than either
one
10 a Sample answer 1 __ 2 cup dried fruit to 1 __
8 cup
sunflower seeds in a granola recipe
b The ratio would not change if the recipe were
tripled because both numbers in the ratio would
be multiplied by the same number and therefore
the ratio would still be equivalent to what it was
originally
c 1 __ 2 divide 1 __
8 = 1 ___
1 2 times 8
4 __
1 = 4 __
1 = 4
Sample answer 4 cups dried fruit per 1 cup
sunflower seeds
11 10 songs
____________ 2 commercials
= 5 songs ____________
1 commercials
12 a Terrancersquos rate
6 mi divide ( 1 __ 2 h ) = 6 __
1 times 2 __
1
= 12 miles per hour
Jessersquos rate
2 mi divide ( 15 min ) = 2 __ 1 divide 1 __
4
= 2 __ 1 times 4 __
1 mi ___ h
= 8 miles per hour
b Terrance
50 mi divide ( 12 mi ___ h ) = 50 ___
1 times 1 ___
12
= 50 ___ 12
h
= 4 1 __ 6 h
= 4 10 ___ 60
h
= 4 hours and 10 minutes
Jesse
50 mi divide ( 8 mi ___ h ) = 50 ___
1 times 1 __
8
= 50 ___ 8 h
= 6 1 __ 4 h
= 6 15 ___ 60
h
= 6 hours and 15 minutes
c 8 mi divide ( 45 min ) = 8 __ 1 divide 3 __
4
= 8 __ 1 times 4 __
3
= 32 ___ 3
= 10 2 __ 3 miles per hour
Sandrarsquos unit rate is greater than Jessersquos but
lower than Terrancersquos so she runs slower than
Terrance but faster than Jesse
13 1 ___ 10
h = 6 ___ 60
h = 6 min
300 words _________ 6 min
= 50 words per min
1 ___ 12
h = 5 ___ 60
h = 5 min
300 words _________ 5 min
= 60 words per min
Faster Eli typed 50 words per minute in his first test
and 60 words per minute in his second test
Copyright copy by Houghton Mifflin Harcourt 24 All rights reserved
Focus on Higher Order Thinking
14 a For the 10-pack of 21 ounce bars
$1537 divide 10 bars asymp $154 per bar
For the 12-pack of 14 ounce bars
$1535 divide 12 bars asymp $128 per bar
The 12-pack has the better price per bar
b For the 10-pack
$1537 divide ( 10 times 21 oz ) = 1537 divide 21
asymp $073 per ounce
For the 12-pack
$1535 divide ( 12 times 14 oz ) = 1535 divide 168
asymp $091 per ounce
The 10-pack has a better price per ounce
c Sample answer Since I always eat them one bar
at a time the 12-pack is the better choice
15 Yes Half a room in half a day corresponds to a unit
rate of 1 __ 2 room divide ( 1 __
2 day ) = 1 room _____
day so at the same
rate the painter could paint 7 rooms in 7 days
16 Sample answer Take the reciprocal of the rate For
example a rate of 7 gallons per hour is equal to
1 hour per 7 gallons
LESSON 42
Your Turn
3 No the rates are not equal and therefore her speed
was not constant
4 Since the ratio of students to adults is constant the
relationship between them is proportional
students ________ adults
= 12 ___ 1 = 36 ___
3 = 60 ___
5 = 12 students per adult
If s = the number of students and a = the number
of adults then a = 1 ___ 12
s or s = 12a
Guided Practice
1 45 ___ 1 = 45 90 ___
2 = 45 135 ____
3 = 45 180 ____
4 = 45
The relationship is proportional
2 k = y __ x = 10 ___
2 = 5 y = 5x
3 k = y __ x = 2 __
8 = 1 __
4 y = 1 __
4 x
4 With the equation y = kx where k is the constant
of proportionality
Independent Practice
5 k = y __ x = 74 ___
4 = 1850 y = 1850x
6 $1099
_______ 05 days
= $2198 per day
7 Rent-All because it has the lowest price per day
($1850)
8 100 ft _____ 08 s
= 1000 _____ 8 ft __ s = 125 ft __ s
500 ft _____ 31 s
= 5000 _____ 31
ft __ s asymp 1613 ft __ s
1875 ft ______ 15 s
= 1875 ______ 15
ft __ s asymp 125 ft __ s
No Emtiaz assumed the relationship is proportional
but it is not The rate of change is not constant and
so his answer is not reasonable
9 $3125
______ 5 h
= $625 per hour and $5000
______ 8 h
= $625 per
hour Because the two unit rates are the same the
relationship between charge and time is proportional
10 The constant rate of change in this context means
that Steven charges $625 per hour
11 y = $625x where x is the number of hours Steven
babysits and y is the amount Steven charges
12 y = $625 ( 3 ) = $1875
13 300 ft _____ 2 min
= 6750
_____ 45
= 150 feet per minute
150 ft _____ min
times 60 min ______ 1 h
= 9000 feet per hour
14 y = 150x
15 Sample answer Feet per minute A submarine may
stay submerged for hours but it would not dive for
hours
Focus on Higher Order Thinking
16 Yes because there is a proportional relationship
so the distance and the time would increase by the
same factor
17 Sample answer Yes Even though the rates in the
table are not constant per ear of corn due to
rounding there is a constant rate for every 3 ears
of corn
LESSON 43
Your Turn
1 No because 11 ___ 1 ne 16 ___
2 Also the line drawn through
the points does not go through the origin
5 a The point ( 4 60 ) represents that the bicyclist can
ride a distance 60 miles in 4 hours
b k = 60 mi _____ 4 h
= 15 mi ___ h
c y = 15x where x is time in hours and y is
distance in miles
Guided Practice
1
Time (h) 3 5 9 10
Pages 195 325 585 650
Proportional the rate is a constant 65 pages
per hour
2
Time (h) 2 3 5 8
Earnings 15 2250 3750 60
Proportional the rate of is a constant $750 per hour
Copyright copy by Houghton Mifflin Harcourt 25 All rights reserved
3 Not proportional the relationship is linear but a line
drawn connecting the points will not pass through
the origin of ( 0 0 )
4 Proportional a line can be drawn that passes
through the points and also the origin of ( 0 0 )
5 k = 28 ft ____ 8 s
= 7 __ 2 ft __ s = 35 ft __ s y = 7 __
2 x or y = 35x where
x = time in seconds and y = height in feet
6 k = $2 ______
8 items = 1 __
4
$ _____
items = 025
$ _____
items so y = 1 __
4 x or
y = 025x where x = number of items and
y = cost in dollars
7 The graph is a straight line passing through the
origin
Independent Practice
8 It is the distance ( 0 miles ) that each horse runs in
0 minutes
9 Horse A runs 1 mile in 4 minutes
Horse B runs 1 mile in 25 minutes
10 For Horse A y = 1 __ 4 x
For Horse B y = 1 ___ 25
x or 2 __ 5 x
11 If x is time in minutes and y is distance in miles in
12 minutes Horse A will run 3 miles or 1 __ 4 ( 12 ) = 3
and Horse B will run 48 miles or 2 __ 5 ( 12 ) = 24 ___
5 = 48
12 Students may draw any straight line with a slope
steeper than 2 __ 5 that starts at the origin of ( 0 0 ) An
example is given below
2
2
4
6
8
10
4 6 8 10Time (min)
Dis
tanc
e (m
i)
A
B
O
13 Yes if the train is traveling at a constant speed the
ratio of miles traveled to time in hours will be
constant and therefore a graph comparing miles to
hours will form a straight line that passes through
the origin of ( 0 0 )
14 Sample answer When comparing relationships that
may be easier to observe on a graph than in an
equation
15 a
2
8
16
24
32
40
4 6 8 10DVDs
Cost
($)
O
b Sample answer The graph will pass through the
point ( 4 20 ) This point shows that four DVDs will
cost $20
16 The graph passes through the point ( 4 8 ) so
Glenda swam 8 feet in 4 seconds
17 Yes The graph is linear and passes through the
origin and therefore the rate of distance to time is
proportional at each point on the line
18 k = 8 ft ___ 4 s
= 2 ft __ s so y = 2x where x is time in
seconds and y is distance swam in feet It would
take 22 minutes to swim 1 __ 2 mile at this rate
Focus on Higher Order Thinking
19 Divide the second coordinate by the first to find the
constant of proportionality k Substitute the value of
k into the equation y = kx Then choose a value for x
and solve for y to find the ordered pair
20 Car 3 is not traveling at a constant speed
because 65 ___ 1 ne 85 ___
2
21 Since Car 4 is traveling at twice the speed it will
travel twice the distance as Car 2 in the same
amount of time Therefore the values in Car 4rsquos
distance column will be twice that shown in Car 2rsquos
distance column
MODULE 4
Ready to Go On
1 $140
_____ 18 ft 2
= $778 per square foot
2 $299
_____ 14 lb
asymp $021 per pound
3 $56 ______
25 gal = $224 per gallon
$3205
______ 15 gal
asymp $214 per gallon this is the better deal
4 $160
_____ 5 g
= $3200 per gram this is the better deal
$315
_____ 9 g
asymp $3500 per gram
5 No The ratio of dollars earned to lawns mowed is
not constant 15 ___ 1 ne 48 ___
3
Copyright copy by Houghton Mifflin Harcourt 26 All rights reserved
6 k = $9
___ 8euro
= $27 ____
24euro = 9 __
8 $ __
euro or 1125
$ __
euro So y = 9 __
8 x or
y = 1125x where x equals the number of euros
and y equals their value in dollars
7 The graph passes through the point ( 2 5 )
so k = 5 __ 2 servings
_______ pt
or k = 25 servings
_______ pt
Therefore
y = 5 __ 2
x or y = 25x where x equals the number
of pints and y equals the number of servings
8 The new graph will pass through the points ( 0 0 ) and ( 3 2 )
2
2
4
6
8
10
4 6 8 10Pints
Serv
ings
Frozen Yogurt
O
Therefore y = 2 __ 3 x where x equals the number of
pints and y equals the number of servings
9 Sample answer Compare corresponding values of
the variables to determine whether there is a
constant rate
Copyright copy by Houghton Mifflin Harcourt 27 All rights reserved
MODULE 5 Proportions and Percent
Are You Ready
1 22 = 22 ____ 100
= 022
2 75 = 75 ____ 100
= 075
3 6 = 6 ____ 100
= 006
4 189 = 100 + 89
= 100 ____ 100
+ 89 ____ 100
= 1 + 089
= 189
5 059 = 59
6 098 = 98
7 002 = 2
8 133 = 133
9 64
_ timesthinsp05
320
32
10 30
_ timesthinsp007
210
21
11 160
_ timesthinsp015
800
_ +1600
2400
24
12 62
_ timesthinsp032
124
_ +thinsp1860
1984
1984
13 4
_ timesthinsp12
8
_ +thinsp40
48
48
14 1000
_ timesthinsp006
6000
60
LESSON 51
Your Turn
2 x = ( $64 - 52 )
__________ $52
x = $12
____ $52
asymp 23
4 x = ( 18 - 12 )
________ 18
x = 6 ___ 18
asymp 33
5 x = ( 16 - 10 )
________ 16
x = 6 ___ 16
= 375
8 010 times $499 = $4990
$499 + $4990 = $54890
9 030 times $499 = $14970
$499 - $14970 = $34930
Guided Practice
1 x = ( $8 - $5 )
_________ $5
x = $3
___ $5
= 60
2 x = ( 30 - 20 )
_________ 20
x = 10 ___ 20
= 50
3 x = ( 150 - 86 )
__________ 86
x = 64 ___ 86
asymp 74
4 x = ( $389 - $349 )
______________ $349
x = $040
_____ $349
asymp 11
5 x = ( 14 - 13 )
________ 13
x = 1 ___ 13
asymp 8
6 x = ( 16 - 5 )
________ 5
x = 11 ___ 5 = 220
7 x = ( 64 - 36 )
_________ 36
x = 28 ___ 36
asymp 78
8 x = ( 80 - 64 )
_________ 80
x = 16 ___ 80
= 20
9 x = ( 95 - 68 )
_________ 95
x = 27 ___ 95
asymp 28
Copyright copy by Houghton Mifflin Harcourt 28 All rights reserved
10 x=( 90-45)_________
90
x=45___90
=50
11 x=( 145-132)__________
145
x=13____145
asymp9
12 x=( 64-21)_________
64
x=43___64
asymp67
13 x=( 16-0)________
16
x=16___16
=100
14 x=( 3-1__
2)_______
3
x=21__
2___
3 asymp83
15 010times$900=$090 $900+$090=$990
16 025times48=12 48-12=36cookies
17 020times340=68 $340-68=272pages
18 050times28=14 28+14=42members
19 004times$29000=$1160 $29000-$1160=$27840
20 130times810=1053 810+1053=1863songs
21 030times20=6 20+6=26miles
22 Dividetheamountofchangeinthequantitybytheoriginalamountthenexpresstheanswerasapercent
Independent Practice23
ItemOriginal
PriceNew Price
Percent Change
Increase or
DecreaseBike $110 $96 asympthinsp13 Decrease
Scooter $45 $56 asympthinsp24 Increase
TennisRacket $79 $8295 5 Increase
Skis $580 $435 25 Decrease
24 a 55
x=( 8-3)_______
8 =5__
8=625
x=( 12-7)________
12 =5___
12asymp417
Theamountofchangeisthesamebutthepercentofchangeislessfrom2010to2011
b Changewasgreatestbetween2009and2010
x=( 12-3)________
3
x=9__3=300increase
25 a Amountofchange=( 5-4)=1
Percentdecrease=1__5=20
b $100_____5 =$020each$100_____
4 =$025each
Amountofchange=$025-$020=$005
Percentincrease=$005_____$020
=25
26 Percenterror=( 136-133)___________
136 times100
=03____136
times100asymp2
Focus on Higher Order Thinking
27 a Theyhavethesame$100+$10=$110and$100+10( $100)=$110
b SylviahasmoreLeroihas$110+$10=$120andSylviahas$110+10( $110)=$121
c BecauseSylviawillhavemoreafterthesecondadditionaldepositandshewillbedepositingincreasingamountsshewillalwayshavemoreinheraccount
28 Thefinalamountisalways0becausea100decreaseofanyamountwouldbe0
29 NoOnlythefirstwithdrawalis$10Eachwithdrawalafterthatislessthan$10becauseitis10oftheremainingbalanceTherewillbemoneyleftafter10withdrawals
LESSON 52
Your Turn
2 a 1c+01c11c
b s=11times$28=$3080
3 a 200
b 1c+2c3c
5 a
1b - 024b
1b024b
b 1b-024b=076b
6 a 1p-005p095p
b 095p=$1425
CopyrightcopybyHoughtonMifflinHarcourt 29 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U2M05indd 29 103113 214 AM
Guided Practice
1 a 035s
b 1s + 035s 135s
c 135 times $3200 = $4320
d 035 times $3200 = $1120
Item Price Markup MarkupRetail
Price
2 Hat $18 15 $270 $2070
3 Book $2250 42 $945 $3195
4 Shirt $3375 75 $2531 $5906
5 Shoes $7499 33 $2475 $9974
6 Clock $4860 100 $4860 $9720
7 Painting $18500 125 $23125 $41625
8 $4500 - 022 ( $4500 ) = $3510
9 $8900 - 033 ( $8900 ) = $5963
10 $2399 - 044 ( $2399 ) = $1343
11 $27999 - 075 ( $27999 ) = $7000
12 Write the percent of markdown as a decimal
subtract the product of this decimal and the regular
price from the regular price
Independent Practice
13 a 046b
b 1b - 046b 054b
c 054 times $2900 = $1566
d 046 times $2900 = $1334
14 Regular Price $329
Sale Price $201
Regular Price $419
Sale Price $245
Regular Price $279
Sale Price $115
Regular Price $309
Sale Price $272
Regular Price $377
Sale Price $224
15 a Sample answer original price $100 final price
$050
b Sample answer original price $100 final price
$9950
c Sample answer original price $100 final price
$350
16 p = 127 ( $7400 ) = $9398
s = 127 ( $4800 ) = $6096
j = 127 ( $32500 ) = $41275
2 ( 9398 ) + 3 ( $6096 ) + $41275 = $78359
17 Either buy 3 get one free or 1 __ 4 off Either case would
result in a discount of 25 which is better than 20
Focus on Higher Order Thinking
18 No she is taking a loss Her cost for the tea is t so
the retail price is 12t The discounted price is
08 ( 12t ) or 096t which is less than t
19 No first change 201 decrease second change
251 increase The second percent change is
greater
20 Rafael can purchase the coat after 11 or 12 weeks
after 11 weeks the price is $10932 after 12 weeks
the price is $10385 and after that Danielle donates
the coat
LESSON 53
Your Turn
1 005 times $2000 = $100 $100 + $2000 = $2100
3 005 times $40000 = $2000
$2000 times 4 years = $8000
$40000 + $8000 = $48000
4 Commission $4500 times 00375 = $16875
Total $2200 + $16875 = $236875
Guided Practice
1 005 times $3000 = $150
2 015 times $7000 = $1050
3 0004 times $10000 = $040
4 15 times $2200 = $3300
5 001 times $8000 = $080
6 20 times $500 = $1000
7 a 007 times $4399 = $308
b $4399 + $308 = $4707
8 115 times $7550 = $8683
9 007 times $2000 = $140
$140 times 5 years = $700
10 003 times $550 = $1650
$1650 times 10 years = $165
$550 + $165 = $715
11 a 090 times $20 = $18
b 1085 times $18 = $1953
12 020 times $2999 = $600 tip
00625 times $2999 = $187 tax
$2999 + $600 + $187 = $3786 total
13 Write the tax rate as a decimal Then multiply the
decimal by the price of the item and add the result
to the price
Independent Practice
14 $3275 + $3988 = $7263 total meal cost
014 times $7263 = $1017 tip
$7263 + $1017 = $8280 total with tip
15 $7865 times 015 = $1180 meal discount
$7865 times 020 = $1573 tip
$7865 + $1573 - $1180 = $8258 total
16 $125 times 235 = $29375 retail ring cost
0075 times $29375 = $2203 tax
$29375 + $2203 = $31578 total with tax
Copyright copy by Houghton Mifflin Harcourt 30 All rights reserved
17 $7999 times 012 = $960 discount
$7999 - $960 = $7039 price before tax
$7039 times 10675 = $7514 total with tax
18 4 times $999 times 020 = $799 discount
4 times $999 - $799 = $3197 price before tax
$3197 times 10675 = $3413 total with tax
19 $4500 + 00725 = $32625 commission
$750 + $32625 = $107625 total income
20 $700 times 0055 = $3850 commission
$475 + $3850 = $51350 total income
21 a Multiply Sandrarsquos height by 010 and add the
product to 4 to get Pablorsquos height Then multiply
Pablorsquos height by 008 and add the product to
Pablorsquos height to get Michaelarsquos height
b Using 48 inches for 4 feet
48 inches times 01 = 48 inches so Pablorsquos height is
53 inches or 4 feet 5 inches to the nearest inch
53 inches times 008 = 42 inches so Michaelarsquos
height is 57 inches or 4 feet 9 inches to the
nearest inch
22 a $4998 times 05 = $2499 50 discount
$2499 - $1000 = $1499 $10 discount
b $4998 - $1000 = $3998 $10 discount
$3998 times 05 = $1999 50 discount
23 a $95 times 09 = $8550 discounted camera
$8550 + $1599 = $10149 total
b $1599 times 09 = $1439 discounted battery
$95 + $1439 = $10939 total
c Eric should apply the discount to the digital
camera he can save $8
d $10149 times 008 = $812 tax
$10149 + $812 = $10961 total
24 a Store 1 $22 divide 2 = $11
Store 2 $1299 times 09 = $1169
Store 1 charges $11 per shirt and Store 2
charges $1169 Therefore I would save
$069 per shirt at Store 1
b Store 3 $2098 times 045 = $944
Yes It is selling shirts at $944
Focus on Higher Order Thinking
25 Marcus should choose the option that pays $2400
plus 3 of sales He would make $2550 to $2700
per month The other option would pay only $1775
to $2050 per month
26 Percent error = ǀ 132 - 137 ǀ
____________ 137
times 100 = 05 ____ 137
asymp 36
MODULE 5
Ready to Go On
1 x = ( 63 - 36 )
_________ 36
x = 27 ___ 36
= 75 increase
2 x = ( 50 - 35 )
_________ 50
x = 15 ___ 50
= 30 decrease
3 x = ( 72 - 40 )
_________ 40
x = 32 ___ 40
= 80 increase
4 x = ( 92 - 69 )
_________ 92
x = 23 ___ 92
= 25 decrease
5 $60 times 015 = $9
$60 + $9 = $69
6 $32 times 0125 = $4
$32 + $4 = $36
7 $50 times 022 = $11
$50 - $11 = $39
8 $125 times 030 = $3750
$12500 - $3750 = $8750
9 $4800 times 0065 = $312 commission
$325 + $312 = $637 total income
10 $5310
______ $1735
asymp 31
11 Find the amount per hour that Priya makes if she
makes 20 more than James
$700 times 020 = $140
$700 + $140 = $840
Next find the amount Slobhan makes if he makes
5 less than Priya
$840 times 005 = $042
$840 - $042 = $798
Slobhan makes $798 per hour
12 Both the 6 tax and the 20 tip are applied to the
initial cost of the meal so the two percents can be
added together and multiplied by the cost
$45 times 026 = $1170
$45 + $1170 = $5670
The total cost of the meal is $5670
13 Sample answer sales tax increase discount
decrease tip increase
Copyright copy by Houghton Mifflin Harcourt 31 All rights reserved
MODULE 6 Expressions and Equations
Are You Ready
1 5 + x
2 11 - n
3 -9 ___ y
4 2x - 13
5 2x + 3
= 2 ( 3 ) + 3
= 6 + 3
= 9
6 -4x + 7
= -4 ( 1 ) + 7
= -4 + 7
= 11
7 15x - 25
= 15 ( 3 ) - 25
= 45 - 25
= 2
8 04x + 61
= 04 ( -5 ) + 61
= -20 + 61
= 41
9 2 __ 3 x - 12
= 2 __ 3
( 18 ) - 12
= 2 __ 3
times ( 18 ___ 1 ) - 12
= 36 ___ 3 - 12
= 0
10 - 5 __ 8
x + 10
= - 5 __ 8 ( -8 ) + 10
= - 5 __ 8 times- 8 __
1 + 10
= - 5 ___ 1 8
times- 8 1 __
1 + 10
= - 5 __ 1 times- 1 __
1 + 10
= 5 + 10
= 15
11 1 __ 2 divide 1 __
4
= 1 times 4 _____ 2 times 1
= 1 times 4 2 ______
1 2 times 1
= 1 times 2 _____ 1 times 1
= 2
12 3 __ 8 divide 13 ___
16
= 3 __ 8 times 16 ___
13
= 3 times 16 2 _______
1 8 times 13
= 3 times 2 ______ 1 times 13
= 6 ___ 13
13 2 __ 5 divide 14 ___
15
= 2 __ 5 times 15 ___
14
= 1 2 times 15
3 ________
1 5 times 14 7
= 1 times 3 _____ 1 times 7
= 3 __ 7
14 4 __ 9 divide 16 ___
27
= 4 __ 9 times 27 ___
16
= 1 4 times 27
3 ________
1 9 times 16 4
= 1 times 3 _____ 1 times 4
= 3 __ 4
LESSON 61
Your Turn
2 ( 3x + 1 __ 2 ) + ( 7x - 4 1 __
2 )
= 3x + 7x + 1 __ 2 - 4 1 __
2
= 10x - 4
3 ( -025x - 3 ) - ( 15x + 14 ) = -025x - 3 - 15x - 14
= -175x - 44
4 02(3b - 15c) + 6c
= 06b - 3c + 6c
= 06b + 3c
5 2 __ 3 (6e + 9f - 21g) - 7f
= 4e + 6f - 14g - 7f
= 4e - f - 14g
6 5x - 3(x - 2) - x
= 5x - 3x + 6 - x
= x + 6
7 83 + 34y - 05(12y - 7)
= 83 + 34y - 6y + 35
= 118 - 26y
Solutions KeyExpressions Equations and Inequalities
UNIT
3
Copyright copy by Houghton Mifflin Harcourt 32 All rights reserved
Guided Practice
1 baseballs 14 + (12)n tennis balls 23 + (16)n
14 + 12n + 23 + 16n
14 + 23 + 12n + 16n
37 + 28n
So the total number of baseballs and tennis balls is
37 + 28n
2 37 + 28n
37 + 28 ( 9 )
= 37 + 252
= 289
3 14 + 5(x + 3) - 7x = 14 + 5x + 15 - 7x
= 29 - 2x
4 3 ( t - 4 ) - 8 ( 2 - 3t ) = 3t - 12 - 16 + 24t
= 27t - 28
5 63c - 2 ( 15c + 41 ) = 63c - 3c - 82
= 33c - 82
6 9 + 1 __ 2 ( 7n - 26 ) - 8n = 9 + 35n - 13 - 8n
= -4 - 4 1 __ 2 n
7 2x + 12
2 ( x + 6 )
8 12x + 24
12 ( x + 2 )
9 7x + 35
7 ( x + 5 )
10 You multiply numbers or expressions to produce a
product You factor a product into the numbers or
expressions that were multiplied to produce it
Independent Practice
11 Let d = number of days
Fee for 15 food booths 15 ( 100 + 5d ) Fee for 20 game booths fee 20 ( 50 + 7d ) Amount the company is paid for the booths
15 ( 100 + 5d ) + 20 ( 50 + 7d ) = 15 ( 100 ) + 15 ( 5d ) + 20 ( 50 ) + 20 ( 7d )
= 1500 + 75d + 1000 + 140d
= 1500 + 1000 + 75d + 140d
= 2500 + 215d
12 New length 96 + l
New width 60 + w
Perimeter of new pattern
2(96 + l) + 2(60 + w)
=2(96) + 2l + 2(60) + 2w
192 + 2l + 120 + 2w
192 + 120 + 2l + 2w
312 + 2l + 2w
13 Width 3
Length 1 x-tile and 2 +1-tiles
Factors 3 and x + 2
Product 3 ( x + 2 ) = 3x + 6
14 Width 4
Length 2 x-tiles and 1 -1-tile
Factors 4 and 2x - 1
Product 4 ( 2x - 1 ) = 8x - 4
15 The area is the product of the length and width
( 6 times 9 ) It is also the sum of the areas of the
rectangles separated by the dashed line ( 6 times 5
and 6 times 4 ) So 6 ( 9 ) = 6 ( 5 ) + 6 ( 4 )
16 Perimeter of triangle ( x + 3 ) + ( 2x + 4 ) +
6x = ( x + 3 ) + ( 2x + 4 ) +
6x = 3x + 7 +
-3x = _ -3x
3x = 7 +
_ -7 = _ -7
3x - 7 =
The length of the side is 3x - 7
17 Perimeter of rectangle 2 ( 3x - 3 ) + 2 ( )
10x + 6 = 2 ( 3x - 3 ) + 2 ( )
10x + 6 = 6x - 6 + 2
_ -6x = _ -6x
4x + 6 = - 6 + 2
_ + 6 = _ + 6
4x + 12 = 2
( 4x + 12 ) divide 2 = ( 2 ) divide 2
2x + 6 =
The length of the side is 2x + 6
18 a P = 2l + 2w
Perimeter of tennis court T
2(2x + 6) + 2(x)
= 4x + 12 + 2x
= 6x + 12
Perimeter of basketball court B
2(3x - 14) + 2( 1 __ 2 x + 32)
= 6x - 28 + x + 64
= 7x + 36
b (7x + 36) - (6x + 12)
= 7x + 36 - 6x - 12
= x + 24
c Find the length of tennis court
Let x = 36
2x + 6 = 2 ( 36 ) + 6
= 72 + 6
= 78
Find the width of the basketball court
Let x = 36
1 __ 2 x + 32 = 1 __
2 ( 36 ) + 32
= 18 + 32
= 50
Find the length of the basketball court
Let x = 36
3x - 14 = 3 ( 36 ) - 14
= 108 - 14
= 94
The tennis court is 36 ft by 78 ft The basketball
court is 50 ft by 94 ft
Focus on Higher Order Thinking
19 Find the area of each small square and rectangle
( x ) ( x ) = x 2
( x ) 1 = x
( 1 ) 1 = 1
Copyright copy by Houghton Mifflin Harcourt 33 All rights reserved
x
x
1
11
1 1
x2 x x x
x 1 1 1x 1 1 1
Area =
x 2 + x + x + x + x + x + 1 + 1 + 1 + 1 + 1 + 1
= x 2 + 5x + 6
( x + 3 ) ( x + 2 ) = x 2 + 5x + 6
20 Agree To find 58 times 23 let 23 = 3 + 20 Then find
the product 58 ( 3 + 20 ) First step 58 ( 3 ) = 174
Second step 58 ( 20 ) = 1160 Third step 174 +
1160 = 1334 So 58 ( 23 ) = 58 ( 3 ) + 58 ( 20 )
21 ( 1 ) Think of 997 as 1000 - 3 So 8 times 997 = 8 ( 1000 - 3 ) By the Distributive Property
8 ( 1000 - 3 ) = 8000 - 24 = 7976
( 2 ) Think of 997 as 900 + 90 + 7 By the Distributive
Property 8 ( 900 + 90 + 7 ) = 7200 + 720 + 56 =
7976
LESSON 62
Your Turn
1 49 + z = -9
_ -49 _ -49
z = -139
2 r - 171 = -48
_ +171 _ +171
r = 123
3 -3c = 36
-3c ____ -3
= 36 ___ -3
c = -12
5 x - 15 = 525
_ +15 _ +15
x = 675
The initial elevation of the plane is 675 miles
6 x ___ 35
= -12
x ___ 35
( 35 ) = -12 ( 35 )
x = -42
The decrease in the value of the stock was $420
7 25x = 75
25x ____ 25
= 75 ___ 25
x = 3
The power was restored in 3 hours
Guided Practice
1 Let x represent the number of degrees warmer the
average temperature is in Nov than in Jan
x + ( -134 ) = -17 or x - 134 = -17
x - 134 = -17
_ +134 _ +134
x = 117
The average temperature in November is 117degF
warmer
2 Let x represent the number of days it takes the
average temperature to decrease by 9degF
-1 1 __ 2 x = -9
( - 2 __ 3 ) ( - 3 __
2 x ) = ( - 2 __
3 ) ( -9 )
x = 18 ___ 3
x = 6
It took 6 days for the temperature to decrease by 9degF
3 -2x = 34
-2x ____ -2
= 34 ___ -2
x = -17
4 y - 35 = -21
_ + 35 _ + 35
y = 14
y = 14
5 2 __ 3 z = -6
( 3 __ 2 ) 2z ___
3 = ( 3 __
2 ) ( -6 )
z = -9
6 Sample answer It helps me describe the problem
precisely and solve it using inverse operations
Independent Practice
7 Let x equal the elevation of Mt Everest
x - 870737 = 203215
_ +870737 _ +870 737
x = 2902887
The elevation of Mt Everest is 2902887 ft
8 Let x equal the number of feet Liam descended
2825131 - x = 2320106
_ -2825131 _ -2825131
-x = - 505025
x = 505025
Liam descended 505025 ft
His change in elevation was -505025 ft
9 Let x equal the elevation of Mt Kenya
2825131 - x = 1119421
_ -2825131 _ -2825131
-x = -1705710
x = 1705710
The elevation of Mt Kenya is 170571 ft
10 Find the change in elevation
1250 - 935 = 315
Use an equation
Let x = the number of minutes the balloon
descends
( -22 1 __ 2 ) x = -315
( - 45 ___ 2 ) x = -315
( - 2 ___ 45
) ( - 45 ___ 2 ) x = -315 ( - 2 ___
45 )
x = 14
It will take the balloon 14 minutes to descend
11 Find the change in elevation
4106 - 3205 = 901
Use an equation to find the rate of descent
Copyright copy by Houghton Mifflin Harcourt 34 All rights reserved
Let x = rate of descent
34x = 901
34x ____ 34
= 901 ____ 34
x = 265 = 26 1 __ 2
The rate of descent was 26 1 __ 2 feet per minute
12 Let x = the number of degrees warmer Montanarsquos
average temperature is than Minnesotarsquos
- 25 + x = -07
_ + 25 _ + 25
x = 18
Montanarsquos average 3-month temperature is 18degC
warmer than Minnesotarsquos
13 Let x = the number of degrees warmer Floridarsquos
average temperature is than Montanarsquos
181 - x = -07
_ - 181 _ -181
-x = -188
x = 188
Floridarsquos average 3-month temperature is 188degC
warmer than Montanarsquos
14 Let x = the number of degrees the average
temperature in Texas would have to change
125 + x = 181
_ -125 _ -125
x = 56
It would have to increase by 56degC
15 Let x = the number of yards the team must get on
their next play
-26 1 __ 3
+ x = 10
+26 1 __ 3
______
+26 1 __ 3
______
x = 36 1 __ 3
The team needs to get 36 1 __ 3 yards on their next play
16 Let x = the number of seconds
( -2 1 __ 2 ) x = -156
( -25 ) x = -156
( -25 _____ -25
) x = -156 ______ -25
x = 624
It takes the diver 624 seconds to reach -156 feet
17 Sample answer The elevation is the product of the
rate and the time
18 Let x = the total amount withdrawn
x __ 5 = 455
( 5 ) x __ 5 = 455 ( 5 )
x = 2275
The total amount she withdrew was $22750
Sample answer
$4550 asymp $50 and $50 times 5 = $250 which is close
to $22750
Focus on Higher Order Thinking
19 ( 1 ) The elevations of the diver and the reef both are
below sea level
( 2 ) The change in the planersquos elevation the plane
descends the plane is moving from a higher to a
lower elevation
20 -4x = -48
( -4x ____ -4
) = -48 _____ -4
x = 12
- 1 __ 4 x = -48
( -4 ) ( - 1 __ 4 ) x = -48 ( -4 )
x = 192
192 ____ 12
= 16
In the first case -4x = -48 you divide both sides
by -4 In the second - 1 __ 4 x = -48 you multiply
both sides by -4 The second solution (192) is
16 times the first (12)
21 Add the deposits and the withdrawals Let x repre-
sent the amount of the initial deposit Write and
solve the equation x + deposits - withdrawals =
$21085
LESSON 63
Your Turn
4 Let x represent the number of video games Billy
purchased
Original balance on gift card $150
Cost for x video games $35 middot x
Final balance on gift card $45
Original balance minus $35 times number of games equals $45
darr darr darr darr darr darr darr $150 - $35 middot x = $45
Equation 150 - 35x = 45
5 Sample answer You order x pounds of coffee from
Guatemala at $10 per pound and it costs $40 to
ship the order How many pounds can you order so
that the total cost is $100
Guided Practice
1
+ + ++ ++
+++ + +
+++
2
----
+ ++ ++
- - -
Copyright copy by Houghton Mifflin Harcourt 35 All rights reserved
3 Let a represent the number of adults that attend
Ticket cost for 1 child = $6
Ticket cost for a adults = $9 middot a
Total cost for movie = $78
cost for child plus $9 times number of adults equals $78
darr darr darr darr darr darr darr $6 + $9 middot a = $78
Equation 6 + 9a = 78
4 x is the solution of the problem
2x is the quantity you are looking for multiplied by 2
+ 10 means 10 is added to 2x
= 16 means the result is 16
5 Sample answer A department store is having a sale
on recliners buy two and get a discount of $125
Sanjay purchases two recliners and the total cost
(before taxes) is $400 What is the price of a single
recliner not including any discounts
6 Choose a variable to represent what you want to
find Decide how the items of information in the
problem relate to the variable and to each other
Then write an equation tying this all together
Independent Practice
7 On one side of a line place three negative variable
tiles and seven +1-tiles and then on the other side
place 28 +1-tiles
8 Let d represent the number of days Val rented the
bicycle
Flat rental fee $5500
Cost for d days of rental $850 middot dTotal cost $123
$850 times number of days plus flat fee equals total cost
darr darr darr darr darr darr darr $850 bull d + $55 = $123
Equation 85d + 55 = 123
9 Let r represent the number of refills
Refill mug cost $675
Cost for r refills $125 middot r Total cost $3175
$125 times number of refills plus refill mug cost equals total cost
darr darr darr darr darr darr darr $125 bull r + $675 = $3175
Equation 125r + 675 = 3175
10 Let n represent the number of weekday classes
The Saturday class lasts 60 minutes
The length of time for the weekday classes is 45 middot n
The total number of minutes for all classes in a week
is 28545 minutes times number of plus minutes for equals total minutes
weekday classes Saturday class
darr darr darr darr darr darr darr45 bull n + 60 = 285
Equation 45n + 60 = 285
11 Let n represent the number of African animals
Half the number of African animals is 1 __ 2 n
45 more than the number of African animals
means + 45
The total number of animals is 172
half times number of and 45 more than number equals total number
African animals of African animals of animals
darr darr darr darr darr darr
1 _ 2
bull n + 45 = 172
Equation 1 __ 2 n + 45 = 172
12 Let u represent the number of uniforms
Cost for basketball equipment $548
Cost for u uniforms $2950 middot uTotal cost $2023
$2950 times number of plus cost for basketball equals total cost
uniforms equipment
darr darr darr darr darr darr darr $2950 bull u + $548 = $2023
Equation 295u + 548 = 2023
13 Let x represent the number of weeks
Initial amount in account $500
$20 per week 20 middot xFinal amount in account $220
initial amount minus 20 times number of equals final amount
weeks
darr darr darr darr darr darr darr 500 - 20 bull x = 220
Equation 500 - 20x = 220
14 a The equation adds 25 but Deenarsquos scenario
involves subtracting 25
b Let x represent the number of shirts
Cost of shirts before discount 9 middot xDiscount means subtract
Amount of discount $25
Total bill $88
9 times number of minus discount equals total
shirts bill
darr darr darr darr darr darr darr 9 bull x - 25 = 88
Equation 9x - 25 = 88
c Sample answer I bought some shirts at the store
for $9 each and a pair of jeans for $25 making
my bill a total of $88 How many shirts did I buy
15 a Let c represent the number of children
Flat fee for Sandy $10
Cost per child for Sandy $5 middot cTotal charge for Sandy $10 + $5c
Total charge for Kimmi $25
To compare the two costs set these values equal
Equation 10 + 5c = 25
b Solve the equation to find c the number of
children a family must have for Sandy and Kimmi
to charge the same amount
10 + 5c = 25
10 - 10 + 5c = 25 - 10
5c = 15
5c ___ 5 = 15 ___
5
c = 3
3 children
c They should choose Kimmi because she charges
only $25 If they chose Sandy they would pay
10 + 5 ( 5 ) = $35
Copyright copy by Houghton Mifflin Harcourt 36 All rights reserved
Focus on Higher Order Thinking
16 To get Andresrsquo equation you can multiply every
number in Peterrsquos equation by 4 To get Peterrsquos
equation you can divide every number in Andrewrsquos
equation by 4 or multiply by 1 __ 4
17 Part of the equation is written in cents and part in
dollars All of the numbers in the equation should be
written either in cents or dollars
18 Sample answer Cici has a gift card with a balance
of 60 She buys several T-shirts for $8 each Her new
balance is $28 after the purchases Write an
equation to help find out how many T-shirts Cici
bought
LESSON 64
Your Turn
1 Model the equation
+ ++ +
+ ++ ++ +
+ ++ ++ +
++
Remove 5 +1-tiles from each side of the mat
+ ++ +
+ ++ ++ +
+ ++ ++ +
++
Divide each side into two equal groups
++
+ ++ +
++
The solution is x = 3
++ ++
2 Model the equation
+ + ++ + ++ +
+++
+++
__
Add 1 +1-tile to each side of the mat Note that
a negative-positive tile pair results in zero
+ + ++ + ++
++ +
+++
+++
__
Divide each side into two equal groups
+ + ++++ + +++
The solution is n = 3
+ + +++
3 Model the equation
++++
______
______
____
Add 3 +1-tiles to each side of the mat Note that
a negative-positive tile pair results in zero
++++
+
++
+
++
______
______
____
Divide each side into two equal groups
++++
____
The solution is a = -1
++ __
Copyright copy by Houghton Mifflin Harcourt 37 All rights reserved
4 Model the equation
____
________
++
Add 2 -1-tiles to each side of the mat Note that
a negative-positive tile pair results in zero
________
________
++
____
Divide each side into two equal groups
________
________
We get -y = -1
____
In order to change -y to y add a positive y-variable
tile to each side
++
__ ++ __
Add 1 +1-tile to each side of the mat
++++
__
The solution is y = 1
+++
6 3n + 10 = 37
Solve the equation for n
3n + 10 = 37
-10 ____
-10 ____
3n = 27
3n ___ 3 = 27 ___
3
n = 9
The triplets are 9 years old
7 n __ 4 - 5 = 15
Solve the equation for n
n __ 4 - 5 = 15
+5 ___
+5 ___
n __ 4 = 20
n __ 4 ( 4 ) = 20 ( 4 )
n = 80
The number is 80
8 -20 = 5 __ 9 ( x - 32 )
Solve the equation for x
-20 = 5 __ 9 ( x - 32 )
-20 = 5 __ 9 x - 160 ____
9
+ 160 ____ 9
______
+ 160 ____ 9
______
- 20 ___ 9 = 5 __
9 x
- 20 ___ 9 divide ( 5 __
9 ) = 5 __
9 x divide ( 5 __
9 )
4 20 times 9
1 _______
9 1 times 5
1 = x
- 4 __ 1 = x
-4 = x
The temperature in the freezer is -4degF
9 120 - 4x = 92
Solve the equation for x
120 - 4x = 92
-120 _____
-120 _____
- 4x = -28
-4x ____ -4
= -28 ____ -4
x = 7
She had 7 incorrect answers
Copyright copy by Houghton Mifflin Harcourt 38 All rights reserved
Guided Practice
1 To solve the equation with algebra tiles first remove
one +1-tile from both sides Then divide each side
into two equal groups
2 Remove 1 +1-tile from each side
++++
+ +++++++++
Divide each side into two equal groups
++++
++++++++
The solution is x = 4
++ + + + +
3 Let w = the width of the frame
2 times height plus 2 times width equals perimeter
darr darr darr darr darr darr darr darr darr2 bull 18 + 2 bull w = 58
Solve the equation
2 ( 18 ) + 2w = 58
36 + 2w = 58
36 - 36 + 2w = 58 - 36
2w = 22
2w ___ 2 = 22 ___
2
w = 11
The width is 11 inches
4 1200 minus 25x = 500
Solve the equation for x
1200 - 25x = 500
_ -1200 _ -1200
-25x = -700
-25x _____ -25
= -700 _____ -25
x = 28
The manager will reorder in 28 days
5 Use the inverse operations of the operations
indicated in the problem If the equation does
not involve parentheses use addition or subtraction
before multiplication or division to solve the
equation
Independent Practice
6 9s + 3 = 57
9s + 3 - 3 = 57 - 3
9s = 54
9s ___ 9 = 54 ___
9
s = 6
7 4d + 6 = 42
4d + 6 - 6 = 42 - 6
4d = 36
4d ___ 4 = 36 ___
4
d = 9
8 115 - 3y = -485
115 - 115 - 3y = -485 - 115
thinsp-3y = -60
-3y
____ -3
= -60 ____ -3
y = 20
9 k __ 2 + 9 = 30
k __ 2 + 9 - 9 = 30 - 9
k __ 2 = 21
2 sdot k __ 2 = 2 sdot 21
k = 42
10 g
__ 3 - 7 = 15
g
__ 3 - 7 + 7 = 15 + 7
g
__ 3 = 22
3 sdot g
__ 3 = 3 sdot 22
g = 66
11 z __ 5 + 3 = -35
z __ 5 + 3 - 3 = -35 - 3
z __ 5 = -38
5 sdot z __ 5 = 5 ( -38 )
z = -190
12 -9h - 15 = 93
-9h - 15 + 15 = 93 + 15
-9h = 108
-9h ____ -9 = 108 ____
-9
h = -12
13 - 1 __ 3 (n + 15) = -2
- 1 __ 3 n - 5 = -2
- 1 __ 3 n - 5 + 5 = -2 + 5
- 1 __ 3 n = 3
-3 sdot - 1 __ 3 n = -3 sdot 3
n = -9
14 -17 + b __ 8 = 13
-17 + 17 + b __ 8 = 13 + 17
b __ 8 = 30
8 sdot b __ 8 = 8 sdot 30
b = 240
Copyright copy by Houghton Mifflin Harcourt 39 All rights reserved
15 7 ( c - 12 ) = -21
7c - 84 = -21
_ +84 _ +84
7c = 63
7c ___ 7 = 63 ___
7
c = 9
16 -35 + p
__ 7 = -52
-35 + 35 + p
__ 7 = -52 + 35
p
__ 7 = -17
7 sdot p
__ 7 = -17 sdot 7
p = -119
17 46 = -6t - 8
46 + 8 = -6t - 8 + 8
54 = -6t
54 ___ -6
= -6t ____ -6
t = -9
18 Let a = the original amount in the account
Double the (original plus 26) equals new
sum of amount amount
darr darr darr darr darr darr
2 (a + $26) = $264
Solve the equation
2 ( a + 26 ) = 264
2 ( a + 26 )
_________ 2 = 264 ____
2
a + 26 = 132
a + 26 - 26 = 132 - 26
a = 106
Puja originally had $106 in the account
19 Let t = the temperature 6 hours ago
Twice temperature less 6 degrees equals current
6 hours ago temperature
darr darr darr darr darr darr 2middot t - 6 = 20
Solve the equation
2t - 6 = 20
2t - 6 + 6 = 20 + 6
2t = 26
2t __ 2 = 26 ___
2
t = 13
Six hours ago it was 13 degF in Smalltown
20 -35 = 5 __ 9 ( x - 32 )
-35 = 5 __ 9 x - 160 ____
9
+ 160 ____ 9
______
+ 160 ____ 9
- 155 ____ 9 = 5 __
9 x
thinsp- 155 ____ 9 divide ( 5 __
9 ) = 5 __
9 x divide ( 5 __
9 )
-thinsp 31
155 times 9
1
= x
9 1
times 5
1
- 31 ___ 1 = x
-31 = x
The temperature is -31degF
21 Let a = Artaudrsquos ageopposite of Artaudrsquos age add 40 equals 28
darr darr darr darr darr darr(-) a + 40 = 28
Solve the equation
-a + 40 = 28
-a + 40 - 40 = 28 - 40
-a = -12
-a ___ -1
= -12 ____ -1
a = 12
Artaud is 12 years old
22 Let c = number of customers when Sven startedtwice number of
customers when Sven started
plus 11 more equals present number of customers
darr darr darr darr darr2 middot c +11 = 73
Solve the equation
2c + 11 = 73
2c + 11 - 11 = 73 - 11
2c = 62
2c ___ 2 = 62 ___
2
c = 31
Sven had 31 customers when he started
23 Let p = original price of the jacket
half original less $6 equals amount
price paid
darr darr darr darr darr
1 __ 2
middot p -6 = 88
Solve the equation
1 __ 2 p - 6 = 88
1 __ 2 p - 6 + 6 = 88 + 6
1 __ 2 p = 94
2 sdot 1 __ 2 p = 2 sdot 94
p = 188
The original price was $188
Copyright copy by Houghton Mifflin Harcourt 40 All rights reserved
24 115 minus 8n = 19
Solve the equation for n
115 - 8n = 19
_ -115 _ -115
-8n = -96
-8n _____ -8
= -96 _____ -8
n = 12
They had 19 apples left after 12 days
25 -55x + 056 = -164
-55x + 056 - 056 = -164 - 056
-55x = -22
-55x ______ -22
= -22 _____ -22
x = 04
26 -42x + 315 = -651
-42x + 315 - 315 = -651 - 315
-42x = -966
-42x ______ -42
= -966 ______ -42
x = 23
27 k ___ 52
+ 819 = 472
k ___ 52
+ 819 - 819 = 472 - 819
k ___ 52
= -347
52 sdot k ___ 52
= 52 ( -347 )
k = -18044
28 Sample answer -3x - 5 = -26
29 Sample answer x __ 5 + 10 = 5
30 When dividing both sides by 3 the student forgot to
divide 2 by 3
3x + 2 = 15
3x ___ 3 + 2 __
3 = 15 ___
3
x + 2 __ 3 = 5
- 2 __ 3
___
- 2 __ 3
___
x = 5 - 2 __ 3
x = 5 times3
___ 1
times3 - 2 __
3
x = 15 ___ 3 - 2 __
3
x = 13 ___ 3 or 4 1 __
3
The solution should be x = 4 1 __ 3
31 a 2(x + 40) = 234
Solve the equation for x
2x + 80 = 234
2x + 80 - 80 = 234 - 80
2x = 154
2x ___ 2 = 154 ____
2
x = 77
Trey saved $77
b Sample answer In both solutions you would
divide $234 by 2 then subtract 40 234 divide 2 ndash 40
= 77 These are the same operations applied in
the same order as when solving the equation
Focus on Higher Order Thinking
32 F = 18c + 32
F - 32 = 18c + 32 - 32
F - 32 = 18c
F - 32 ______ 18
= 18c ____ 18
F - 32 ______ 18
= c
33 P = 2 ( ℓ + w ) P = 2ℓ + 2w
P - 2ℓ = 2ℓ - 2ℓ + 2w
P - 2ℓ = 2w
P - 2ℓ ______ 2 = 2w ___
2
P - 2ℓ ______ 2 = w
34 ax + b = c
ax + b - b = c - b
ax = c - b
ax ___ a = c - b ______ a
x = c - b ______ a
MODULE 6
Ready to Go On
1 Add the amounts for the cost of first day of the field
trip with the second day of the field trip where n is
the number of members in the club
15n + 60 + 12n + 95
Therefore the total cost of the two-day field trip can
be written as the expression 27n + 155
2 h + 97 = -97
_ -97 _ -97
h = -194
3 - 3 __ 4 + p = 1 __
2
+ 3 __ 4 + 3 __
4
p = 1 __ 2 + 3 __
4
p = 1 times2
___ 2
times2 + 3 __
4
p = 2 __ 4 + 3 __
4
p = 5 __ 4
4 -15 = -02k
-15 _____ -02
= -02k ______ -02
75 = k
Copyright copy by Houghton Mifflin Harcourt 41 All rights reserved
5 y ___
-3 = 1 __
6
y ___
-3 ( -3 ) = 1 __
6 ( -3 )
y = 1 __ 6 times -3 ___
1
y = -3 ___ 6
y = -1 ___ 2
6 - 2 __ 3
m = -12
- 2 __
3 m _____
- 2 __ 3 = -12 ____
- 2 __ 3
m = -12 divide - 2 __ 3
m = -12 ____ 1 divide - 2 __
3
m = -12 ____ 1 times - 3 __
2
m = -36 ____ -2
m = 18
7 24 = - t ___ 45
24 ( 45 ) = - t ___ 45
( 45 )
108 = -t
-108 = t
8 Let d represent the number of the day after the first
day for example d = 1 means the first day after the
day he started number of number number
2 times day after plus of sit-ups equals of sit-ups
first day first day today
darr darr darr darr darr darr darr
2 middot d + 15 = 33
Equation 2d + 15 = 33
9 5n + 8 = 43
5n + 8 - 8 = 43 - 8
5n = 35
5n ___ 5 = 35 ___
5
n = 7
10 y __
6 - 7 = 4
y __
6 - 7 + 7 = 4 + 7
y __
6 = 11
6 sdot y __
6 = 6 sdot 11
y = 66
11 8w - 15 = 57
8w - 15 + 15 = 57 + 15
8w = 72
8w ___ 8 = 72 ___
8
w = 9
12 g
__ 3 + 11 = 25
g
__ 3 + 11 - 11 = 25 - 11
g
__ 3 = 14
3 sdot g
__ 3 = 3 sdot 14
g = 42
13 f __ 5 - 22 = -25
f __ 5 - 22 + 22 = -25 + 22
f __ 5 = -03
5 sdot f __ 5 = 5 ( -03 )
f = -15
14 - 1 __ 4 (p + 16) = 2
- 1 __ 4 p - 4 = 2
- 1 __ 4 p - 4 + 4 = 2 + 4
- 1 __ 4 p = 6
-4 sdot - 1 __ 4 p = 6 sdot -4
p = -24
15 Sample answer Analyze the situation to determine
how to model it using a two-step equation Solve
the equation Interpret the solution in the given
situation
Copyright copy by Houghton Mifflin Harcourt 42 All rights reserved
MODULE 7 Inequalities
Are You Ready
1 9w = -54
9w ___ 9 = -54 ____
9
w = -6
2 b - 12 = 3
thinsp _ + 12 = _ + 12
b = 15
3 n __ 4
= -11
4 times n __ 4
= 4 ( -11 )
n = -44
4-7
ndash5ndash10 0 5 10
75 4 6
8 3 - (-5)
3 + 5
8
9 -4 - 5
-9
10 6 - 10
-4
11 -5 - (-3)
-5 + 3
-2
12 8 - (-8)
8 + 8
16
13 9 - 5
4
14 -3 - 9
-12
15 0 - (-6)
0 + 6
6
LESSON 71
Your Turn
4 y minus 5 ge minus7
_ +5 _ +5
y ge minus2
-4-5 -3 -2-1 0 1 2 3 4 5
Check Substitute 0 for y
minus1 ge -8
minus1(minus2) le -8(minus2)
2 le 16
5 21 gt 12 + x
_ -12 _ minus12
9 gt x
x lt 9
10 2 3 4 5 6 7 8 9 10
Check Substitute 8 for x
21 gt 12 + 8
21 gt 12 + 8
21 gt 20
6 -10y lt 60
-10y
_____ -10
lt 60 ____ -10
y gt -6
-10-9 -8 -7 -6 -5 -4 -3 -2-1 0 1
Check Substitute -5 for y
-10y lt 60
-10(-5) lt 60
50 lt 60
7 7 ge - t __ 6
7(-6) le - t __ 6 (-6)
-42 le t
t ge -42
-46 -45 -44 -43 -42 -41 -40-47
Check Substitute -36 for t
7 ge - t __ 6
7 ge - ( -36 ____
6 )
7 ge 6
8 Write and solve an inequality
Let m = the number of months
35m le 315
35m ____ 35
le 315 ____ 35
m le 9
Tony can pay for no more than 9 months of his gym
membership using this account
Guided Practice
1 -5 le -2
_ +7 _ +7
2 le 5
2 -6 lt -3
-6 ___ -3
gt -3 ___ -3
2 gt 1
3 7 gt -4
_ -7 _ -7
0 gtthinsp -11
Copyright copy by Houghton Mifflin Harcourt 43 All rights reserved
4 -1 ge -8
-1 ( -2 ) le -8 ( -2 )
2 le 16
5 n - 5 ge -2
_ +5 _ +5
n ge 3
-5 -4 -3 -2-1 0 3 4 51 2
Check Substitute 4 for n
n - 5 ge -2
4 - 5 ge -2
-1 ge -2
6 3 + x lt 7
_ -3 _ -3
x lt 4
-2-1 0 3 4 5 6 7 81 2
Check Substitute 3 for x
3 + x lt 7
3 + 3 lt 7
6 lt 7
7 -7y le 14
-7y
____ -7 ge 14 ___ -7
y ge -2
-5-6-7 -4 -3 -2-1 0 1 2 3
Check Substitute -1 for y
-7y le 14
-7 ( -1 ) le 14
7 le 14
8 b __ 5 gt -1
b __ 5 ( 5 ) gt -1 ( 5 )
b gt -5
-5-6-7-8 -4 -3 -2-1 0 1 2
Check Substitute 0 for b
b __ 5 gt -1
0 __ 5 gt
-1
0 gt -1
9 a -4t ge -80
b -4t ge -80
-4t ____ -4
le -80 ____ -4
t le 20
It will take the physicist 20 or fewer hours to change
the temperature of the metal
c The physicist would have to cool the metal for
more than 20 hours for the temperature of the
metal get cooler than -80deg C
10 You reverse the inequality symbol when you divide
or multiply both sides of an inequality by a negative
number
Independent Practice
11 x - 35 gt 15
_ + 35 _ +35
x gt 50
100 20 30 40 50 60 70 80 90100
Check Substitute 51 for x
x - 35 gt 15
51 minus 35 gt 15
16 gt 15
12 193 + y ge 201
_ -193 _ minus193
y ge 8
10 2 3 4 5 6 7 8 9 10
Check Substitute 9 for y
193 + y ge 201
193 + 9 ge 201
202 ge 201
13 - q
__ 7 ge -1
- q
__ 7 ( -7 ) le -1 ( -7 )
q le 7
8 9 105 6 70 1 2 3 4
Check Substitute ndash14 for q
- q
__ 7 ge -1
- -14 ____ 7 ge
-1
2 ge -1
14 -12x lt 60
-12x _____ -12
gt 60 ____ -12
x gt -5
0-10-9 -8 -7 -6 -5 -4 -3 -2-1
Check Substitute -4 for x
-12x lt 60
-12 ( -4 ) lt 60
48 lt 60
15 5 gt z -3
_ +3 _ +3
8 gt z
z lt 8
10 2 3 4 5 6 7 8 9 10
Check Substitute 7 for z
5 gt z - 3
5 gt 7 - 3
5 gt 4
Copyright copy by Houghton Mifflin Harcourt 44 All rights reserved
16 05 le y __
8
05 ( 8 ) le y __
8 ( 8 )
4 le y
y ge 4
8 9 105 6 70 1 2 3 4
Check Substitute 8 for y
05 le y __
8
05 le 8 __
8
05 le 1
17 Write and solve an inequality
Let x = the number of inches
12 + x le 28
_ -12 _ -12
x le 16
The puppy will grow at most 16 inches more
18 Write and solve an inequality
Let w = the total weight of the kittens
w __ 7 lt 35
w __ 7 ( 7 ) lt 35 ( 7 )
w lt 245
The possible combined weights of the kittens is any
weight less than 245 ounces but greater than 0
19 Write and solve an inequality
Let s = the number of sides
6s le 42
6s ___ 6 le 42 ___
6
s le 7
The length of a side is at most 7 inches
20 Write and solve an inequality
Let x = the amount Tom needs to spend
3025 + x ge 50
_ -3025 _ -3025
x ge 1975
Tom needs to spend at least $1975
21 Write and solve an inequality
Let w = the width of the region
155w ge 1705
155w ______ 155
ge 1705 _____ 155
w ge 11
The possible width of the region is at least 11 feet
22 Write and solve an inequality
Let t = the number of seconds
thinsp-12t lt -120
-12t _____ -12
gt -120 _____ -12
t gt 10
No let t be the number of seconds the descent
takes the inequality is ndash12t lt -120 so t gt 10 so
the submarinersquos descent takes 10 seconds or more
23 Write and solve an inequality
Let s = the amount of spinach
3s le 10
3s ___ 3 le 10 ___
3
s le 3 1 __ 3
The greatest amount of spinach she can buy is 3 1 __ 3
pounds
24 Write and solve an inequality
Let m = the amount of money Gary has
m ___ 05
le 55
m ___ 05
( 05 ) le 55 ( 05 )
m le 275
Gary has at most $275
25 Write and solve an inequality
Let x = the number of pounds of onions
125x le 3
125x _____ 125
le 3 ____ 125
x le 24
No 125x le 3 x le 24 so 24 pounds of onions is
the most Florence can buy 24 lt 25 so she cannot
buy 25 pounds
Focus on Higher Order Thinking
26 If you divide both sides of -7z ge 0 by -7 and do
not reverse the inequality symbol you get z ge 0
This is incorrect because if you choose a value from
the possible solutions such as z = 1 and substitute
it into the original equation you get -7 ge 0 which is
not true
27 x gt 9 for each inequality in each case the number
added to x is 9 less than the number on the right
side of each inequality so x gt 9 is the solution
28 Find the formula for the volume of a rectangular
prism
V = lwh
Write and solve an inequality
Let h = the height in inches
( 13 ) ( 1 __ 2 ) h lt 65
65h lt 65
65h ____ 65
lt 65 ___ 65
h lt 10
All heights greater than 0 in and less than 10 in
( 13 ) ( 1 __ 2 ) h lt 65 65h lt 65 h lt 10 A height cannot
be 0 or less than 0 so h gt 0 and h lt 10
Copyright copy by Houghton Mifflin Harcourt 45 All rights reserved
LESSON 72Your Turn
3 Let a represent the amount each member must
raise
Number of members 45
Starting amount $1240
Target amount $6000
starting number amount each is greater target
amount plus of members times member than or amount
must raise equal to
darr darr darr darr darr darr darr $1240 + 45 middot a ge $6000
Equation 1240 + 45a ge 6000
4 Let n represent the greatest number of rides Ella
can go on
Starting amount $40
Admission price $6
Cost for each ride $3
admission cost for number is less starting
price plus each ride times of rides than or amount
equal to
darr darr darr darr darr darr darr $6 + $3 middot n le $40
Equation 6 + 3n le 40
5 x is the solution of the problem the quantity you
are looking for
3x means that for a reason given in the problem
the quantity you are looking for is multiplied by 3
+ 10 means that for a reason given in the problem
10 is added to 3x
gt 30 means that after multiplying the solution x by
3 and adding 10 to it the result must be greater
than 30
Sample answer An exam consists of one essay
question worth 10 points and several multiple choice
questions worth 3 points each If Petra earns full
points on the essay question how many multiple
choice questions must she get right in order to get
a score greater than 30 points
6 x is the solution of the problem the quantity you are
looking for
5x means that for a reason given in the problem
the quantity you are looking for is multiplied by 5
-50 means that for a reason given in the problem
50 is subtracted from 5x
le 100 means that after multiplying the solution x by
5 and subtracting 50 from it the result must be less
than or equal to 100
Sample answer Miho has $100 to spend on her
garden She spends $50 on gardening supplies
Vegetable plants cost $5 each What is the greatest
number of plants she can buy
Guided Practice
1
- -- -
-
lt
++++++
+ + ++ + +
+
2
---
gt
+ + ++ + +
+ + ++ + +
+ + +
3 Let a represent the amount each member must
raise
Amount to be raised $7000
Amount already raised $1250
Number of members 92 amount number of amount each is greater target
already plus members times member than or amount
raised raises equal to
darr darr darr darr darr darr darr 1250 + 92 times a ge 7000
The inequality that represents this situation is
1250 + 92a ge 7000
4 x is the solution of the problem 7x is the solution
multiplied by 7 -18 means that 18 is subtracted
from 7x le 32 means that the result can be no
greater than 32
5 Sample answer Alexa has $32 to spend on T-shirts
for her friends She has a gift card worth $18 T-shirts
cost $7 each How many T-shirts can Alexa buy
6 Sample answer Choose a variable to represent
what you want to find Decide how the information in
the problem is related to the variable Then write an
inequality
Independent Practice
7 number possible amount is
of times amount each minus for more $200
friends friend earns supplies than
darr darr darr darr darr darr darr 3 middot a - $28 gt $200
3a + 28 gt 200
Let a = possible amount each friend earned
8 cost of number cost of less than amount
bagel times of bagels plus cream or equal Nick
cheese to has
darr darr darr darr darr darr darr $075 middot n + $129 le $700
075n + 129 le 700
Let n = the number of bagels Nick can buy
9 number max amount amount less than total amount
of shirts times each shirt minus of gift or equal Chet can
can cost certificate to spend
darr darr darr darr darr darr darr 4 sdot a - 25 le 75
4a - 25 le 75Let a = the maximum amount each shirt can cost
Copyright copy by Houghton Mifflin Harcourt 46 All rights reserved
10 number of number number of is less total
seats in plus of rows on times seats in than equal number
balcony ground floor one row equal to of people
darr darr darr darr darr darr darr 120 + 32 middot n le 720
120 + 32n le 720
Let n = the number of people in each row
11 amount commission amount greater than earning
earned per plus rate times of sales or equal to for this
month month
darr darr darr darr darr darr darr 2100 + 005 middot s ge 2400
2100 + 005s ge 2400
Let s = the amount of her sales
12 number number average greater
of cans plus of days times number of than goal
collected cans per day
darr darr darr darr darr darr darr 668 + 7 n gt 2000
668 + 7n gt 2000
Let n = the average number of cans collected each
day
13 cost per cost per number of less than total amount
month plus CD times CDs she or equal spent in
buys to a month
darr darr darr darr darr darr darr
$7 + $10 middot c le $100
7 + 10c le 100
Let c = the number of CDs Joanna buys
14 cost of cost for number of less than total amount
belt plus each times shirts he or equal of money
shirt can buy to Lionel has
darr darr darr darr darr darr darr
$22 + $17 middot n le $80
22 + 17n le 80
Let n = the number of shirts he can buy
15 Sample answer Mr Craig is buying pizzas for the
7th grade field day He can spend up to $130 and
needs 15 pizzas He has a $20 coupon How much
can he spend per pizza $10 or less per pizza
16 ldquoat leastrdquo in this case means m ge 25
17 ldquono greater thanrdquo in this case means k le 9
18 ldquoless thanrdquo in this case means p lt 48
19 ldquono more thanrdquo in this case means b le -5
20 ldquoat mostrdquo in this case means h le 56
21 ldquono less thanrdquo in this case means w ge 0
22 The average score of the three tests Marie has
already taken and the three she will still take
is given by
95 + 86 + 89 + 3s
________________ 6
where s is the average score on the three remaining
tests
This value needs to be greater than or equal to 90
so the inequality can be written as
95 + 86 + 89 + 3s
________________ 6 ge 90 or
95 + 86 + 89 + 3s ge 540 or
270 + 3s ge 540
Focus on Higher Order Thinking
23 5 + 10 lt 20 Sample answer If the combined length
of two sides of a triangle is less than the length of
the third side the two shorter sides will not be long
enough to form a triangle with the third side Here
the combined length of 5 ft and 10 ft is 15 ft not
enough to make a triangle
24 -m gt 0 Sample answer Since m is less than 0 it
must be a negative number -m represents the
opposite of m which must be a positive number
since the opposite of a negative number is positive
So -m gt 0
25 n gt 1 __ n if n gt 1
n lt 1 __ n if n lt 1
n = 1 __ n if n = 1
LESSON 73
Your Turn
1 Model the inequality
++
++++
+++
++++
++++
+++
gt
Add seven -1-tiles to both sides of the mat
++
++++
+++
++++
++++
+++
gt
- -- -- --
- -- -- --
Remove zero pairs from both sides of the mat
++
++++
gt
Divide each side into equal groups
++
++++
gt
Copyright copy by Houghton Mifflin Harcourt 47 All rights reserved
The solution is x gt 2
+ + +gt
2 Model the inequality
+++++
----
+++++
+ +++++
ge
Add four +1-tiles to both sides of the mat
+++++
----
+++++
+ ++
++++
+++
++++
ge
Remove zero pairs from the left side of the mat
+++++
+++++
+ +++++
++++
ge
Divide each side into equal groups
+++++
+++++
+ +++++
++++
ge
The solution is h ge 3
+ + + +ge
3 Use inverse operations to solve the inequality
5 - p
__ 6 le 4
5 - 5 - p
__ 6 le 4 - 5
thinsp- p
__ 6 le -1
thinsp-6 ( - p
__ 6 ) ge -6 ( -1 )
p ge 6
Graph the inequality and interpret the circle and
arrow
0 1 4 5 72 3 6 8 9 10
Joshua has to run at a steady pace of at least 6 mih
4 Substitute each value for v in the inequality
3v - 8 gt 22
v = 9 v = 10 v = 11
3 ( 9 ) - 8 gt 22 3 ( 10 ) - 8 gt 22 3 ( 11 ) - 8 gt 22
Evaluate each expression to see if a true inequality
results
3 ( 9 ) - 8 gt 22 3 ( 10 ) - 8 gt
22 3 ( 11 ) - 8 gt
22
27 - 8 gt 22 30 - 8 gt
22 33 - 8 gt
22
19 gt 22 22 gt
22 25 gt
22
not true not true true
v = 11
5 Substitute each value for h in the inequality
5h + 12 le -3
h = -3 h = -4 h = -5
5 ( -3 ) + 12 le -3 5 ( -4 ) + 12 le -3 5 ( -5 ) + 12 le -3
Evaluate each expression to see if a true inequality
results
5 ( -3 ) + 12 le -3 5 ( -4 ) + 12 le
-3 5 ( -5 ) + 12 le
-3
-15 + 12 le -3 -20 + 12 le
-3 -25 + 12 le
-3
-3 le -3 -8 le
-3 -13 le
-3
true true true
h = -3 h = -4 h = -5
Copyright copy by Houghton Mifflin Harcourt 48 All rights reserved
Guided Practice
1 Remove 4 +1-tiles from both sides then divide each
side into 3 equal groups the result is x lt 3
2 Use inverse operations to solve the inequality
5d - 13 lt 32
5d - 13 + 13 lt 32 + 13
5d lt 45
5d ___ 5 lt 45 ___
5
d lt 9
Graph the inequality
20 6 84 10 12 14 16 18 20
3 Use inverse operations to solve the inequality
-4b + 9 le -7
-4b + 9 - 9 le -7 - 9
-4b le -16
-4b ____ -4
ge -16 ____ -4
b ge 4
Graph the inequality
20 6 84 10 12 14 16 18 20
4 Substitute each value for m in the inequality
2m + 18 gt - 4
m = -12 m = -11 m = -10
2 ( -12 ) + 18 gt -4 2 ( -11 ) + 18 gt -4 2 ( -10 ) + 18 gt -4
Evaluate each expression to see if a true inequality
results
2 ( -12 ) + 18 gt -4 2 ( -11 ) + 18 gt
- 4 2 ( -10 ) + 18 gt
- 4
- 24 + 18 gt -4 - 22 + 18 gt
- 4 - 20 + 18 gt
- 4
- 6 gt - 4 - 4 gt
- 4 - 2 gt
- 4
not true not true true
m = -10
5 Substitute each value for y in the inequality
- 6y + 3 ge 0
y = 1 y = 1 __ 2 y = 0
-6 ( 1 ) + 3 ge 0 -6 ( 1 __ 2 ) + 3 ge 0 -6 ( 0 ) + 3 ge 0
Evaluate each expression to see if a true inequality
results
-6 ( 1 ) + 3 ge 0 - 6 ( 1 __
2 ) + 3 ge
0 - 6 ( 0 ) + 3 ge
0
-6 + 3 ge 0 -3 + 3 ge
0 0 + 3 ge
0
-3 ge 0 0 ge
0 3 ge
0
not true true true
y = 1 __ 2
y = 0
6 Solve the inequality
65 - 4t ge 15
65 - 65 - 4t ge 15 - 65
-4t ge -5
-4t ____ -4
le -5 ___ -4
t le 125
Graph the inequality
0 05 1 15 2 25
Lizzy can spend from 0 to 125 h with each student
No 15 h per student will exceed Lizzyrsquos available
time
7 Sample answer Apply inverse operations until you
have isolated the variable If you multiply or divide
both sides of the inequality by a negative number
reverse the direction of the inequality symbol
Independent Practice
8 2s + 5 ge 49
2s + 5 - 5 ge 49 - 5
2s ge 44
2s ___ 2 ge 44 ___
2
s ge 22
10 14 1612 18 20 22 24 26 28 30
9 -3t + 9 ge -21
-3t + 9 - 9 ge -21 -9
-3t ge -30
-3t ____ -3
le -30 ____ -3
t le 10
ndash2ndash4ndash6ndash8ndash10 0 2 4 6 8 10
10 55 gt -7v + 6
55 - 6 gt -7v + 6 - 6
49 gt - 7v
49 ___ -7 lt -7v ____ -7
v gt -7
-10-9 -8 -7 -6 -5 -4 -3 -2 -1 0
11 21 1 __ 3 gt 3m - 2 2 __
3
21 1 __ 3 + 2 2 __
3 gt 3m - 2 2 __
3 + 2 2 __
3
24 gt 3m
24 ___ 3 gt 3m ___
3
8 gt m or m lt 8
0 1 4 5 72 3 6 8 9 10
12 a ___ -8
+ 15 gt 23
a ___ -8
+ 15 - 15 gt 23 - 15
a ___ -8
gt 8
-8 ( a ___ -8
) lt -8 ( 8 )
a lt -64
-70 -68 -66 -64 -62 -60
Copyright copy by Houghton Mifflin Harcourt 49 All rights reserved
13 f __ 2 - 22 lt 48
f __ 2 - 22 + 22 lt 48 + 22
f __ 2 lt 70
2 ( f __ 2 ) lt 2 ( 70 )
f lt 140
100 110 120 130 140 150
14 -25 + t __ 2 ge 50
-25 + 25 + t __ 2 ge 50 + 25
t __ 2 ge 75
2 ( t __ 2 ) ge 2 ( 75 )
t ge 150
130 140 150 160 170 180
15 10 + g ___
-9 gt 12
10 - 10 + g ___
-9 gt 12 - 10
g ___
-9 gt 2
-9 ( g ___
-9 ) lt -9 ( 2 )
g lt -18
-20 -18 -14 -12 -10-16
16 252 le -15y + 12
252 - 12 le -15y + 12 - 12
24 le - 15y
24 ____ -15
ge -15y
_____ -15
y le -16
-20 -18 -14 -12 -10-16
17 -36 ge -03a + 12
-36 - 12 ge -03a + 12 - 12
-48 ge -03a
-48 _____ -03
le -03a ______ -03
a ge 16
10 11 12 13 14 16 17 18 19 2015
18 80 - 2w ge 50
80 - 80 - 2w ge 50 - 80
- 2w ge -30
-2w ____ -2
le -30 ____ -2
w le 15
The width is a positive number no greater than
15 inches the possible widths in inches will be 10
11 12 13 14 and 15
19 Inequality 7n - 25 ge 65
7n - 25 ge 65
7n - 25 + 25 ge 65 + 25
7n ge 90
7n ___ 7 ge 90 ___
7
n ge 12 6 __ 7
Grace must wash at least 13 cars because n must
be a whole number
Focus on Higher Order Thinking
20 No Sample answer If x lt x - 1 then subtracting
x from both sides of the inequality 0 lt -1 That is
untrue so no value of x can be less than x - 1
21 a
10 3 42 5 6 7 8 9 10
b
10 3 42 5 6 7 8 9 10
c A number cannot simultaneously be less than 2
and greater than 7 Therefore there is no number
that satisfies both inequalities
d Consider the graph of x gt 2 and x lt 7
The solution includes all the numbers on the
number line so the solution set is all numbers
22 Sample answer Joseph might have reasoned that n
was first multiplied by 2 then increased by 5 to give
a result less than 13 Working backward he would
have subtracted 5 from 13 ( to get 8 ) then divided by
2 ( to get 4 ) giving n lt 4 Shawnee would have
followed these same steps but would have used a
variable and invers operations
MODULE 7
Ready to Go On
1 n + 7 lt -3
thinsp _ -7
_ -7
n lt -10
2 5p ge -30
5p
___ 5 ge -30 ____
5
p ge -6
3 14 lt k + 11
_ -11 _ -11
3 lt k
4 d ___ -3
le minus6
( -3 ) ( d ) ge ( -3 ) ( -6 )
d ge 18
Copyright copy by Houghton Mifflin Harcourt 50 All rights reserved
5 c - 25 le 25
_ +25 _ +25
c le 5
6 12 ge -3b
12 ___ -3
le -3b _____ -3
-4 le b
7 Let n be the number of minimum points Jose must
score 562 + n ge 650
Solve the inequality
562 + n ge 650
_ -562 _ -562
n ge 88
8 Let t be the number of minutes Lainey can descend
-20 - 20t ge -100
9 2s + 3 gt 15
_ -3 _ -3
2s gt 12
2s ___ 2
gt 12 ___ 2
s gt 6
10 - d ___ 12
- 6 lt 1
_ +6 _ +6
- d ___ 12
lt 7
12 ( - d ___ 12
) lt 12 ( 7 )
-d lt 84
d gt -84
11 -6w - 18 ge 36
_ +18 _ +18
thinsp-6w ge 54
-6w _____ -6
le 54 ___ -6
w le -9
12 z __ 4 + 22 le 38
_ -22 _ -22
z __ 4 le 16
4 ( z __ 4 ) le 4 ( 16 )
z le 64
13 b __ 9 - 34 lt -36
_ +34 _ +34
b __ 9 lt -2
9 ( b __ 9 ) lt 9 ( -2 )
b lt -18
14 -2p + 12 gt 8
-12 ____
-12 ____
-2p gt -4
-2p
____ -2 lt -4 ___
-2
p lt 2
15 Sample answer Look for key words or phrases
that indicate inequality such as ldquogreater thanrdquo
ldquoless thanrdquo ldquoat mostrdquo or ldquoat leastrdquo
Copyright copy by Houghton Mifflin Harcourt 51 All rights reserved
MODULE 8 Modeling Geometric Figures
Are You Ready
1 3x + 4 = 10
3x + 4 - 4 =10 - 4
3x = 6
3x ___ 3 = 6 __
3
x = 2
2 5x - 11 = 34
5x - 11 + 11 = 34 + 11
5x = 45
5x ___ 5 = 45 ___
5
x = 9
3 -2x + 5 = -9
-2x + 5 - 5 = -9 - 5
-2x = -14
-2x ____ -2
= -14 ____ -2
x = 7
4 -11 = 8x + 13
-11 - 13 = 8x + 13 - 13
-24 = 8x
-24 ____ 8 = 8x ___
8
-3 = x
5 4x - 7 = -27
4x - 7 + 7 = -27 + 7
4x = -20
4x ___ 4 = -20 ____
4
x = -5
6 1 __ 2 x + 16 = 39
1 __ 2 x + 16 - 16 = 39 - 16
1 __ 2 x = 23
( 2 ) 1 __ 2 x = ( 2 ) 23
x = 46
7 12 = 2x - 16
12 + 16 = 2x - 16 + 16
28 = 2x
28 ___ 2 = 2x ___
2
14 = x
8 5x - 15 = -65
5x - 15 + 15 = -65 + 15
5x = -50
5x ___ 5 = -50 ____
5
x = -10
9 x __ 5 = 18 ___
30
x times 30 = 5 times 18
30x = 90
30x ____ 30
= 90 ___ 30
x = 3
10 x ___ 12
= 24 ___ 36
x times 36 = 12 times 24
36x = 288
36x ____ 36
= 288 ____ 36
x = 8
11 3 __ 9 = x __
3
3 times 3 = 9 times x
9 = 9x
9 __ 9 = 9x ___
9
1 = x
12 14 ___ 15
= x ___ 75
14 times 75 = 15 times x
1050 = 15x
1050 _____ 15
= 15x ____ 15
70 = x
13 8 __ x = 14 ___ 7
8 times 7 = x times 14
56 = 14x
56 ___ 14
= 14x ____ 14
4 = x
14 14 ___ x = 2 __ 5
14 times 5 = x times 2
70 = 2x
70 ___ 2 = 2x ___
2
35 = x
15 5 __ 6 = x ___
15
5 times 15 = 6 times x
75 = 6x
75 ___ 6 = 6x ___
6
125 = x
Solutions KeyGeometry
UNIT
4
Copyright copy by Houghton Mifflin Harcourt 52 All rights reserved
16 81 ___ 33
= x ____ 55
81 times 55 = 33 times x
4455 = 33x
4455 _____ 33
= 33x ____ 33
135 = x
LESSON 81
Your Turn
6 Length 132 in times 5 ft ____ 3 in
= 22 ft
Width 6 in times 5 ft ____ 3 in
= 10 ft
Area 10 ft ( 22 ft ) = 220 square feet
Guided Practice
1
Blueprint
length (in)3 6 9 12 15 18
Actual
length (ft)5 10 15 20 25 30
a The wall is 30 feet long
b 25 ft times 3 in ____ 5 ft
= 15 in
2 The width is 7 in times 4 ft ____ 2 in
= 14 ft and the length is
14 in times 4 ft ____ 2 in
= 28 ft and the area is
28 ft ( 14 ft ) = 392 square feet
3 Length 10 cm times 5 m _____ 2 cm
= 25 m
Width 6 cm times 5 m _____ 2 cm
= 15 m
Area 25 m ( 15 m ) = 375 square meters
4 a
b Length is 36 m and width is 24 m using both
scales
5 If the scale drawing is complete and accurate you
can use it to find any length or area of the object of
the drawing
Independent Practice
6 a 2 in times 40 cm ______ 1 in
= 80 cm
15 in times 40 cm ______ 1 in
= 60 cm
The dimensions of the painting are 80 cm by 60 cm
b 80 cm times 60 cm = 4800 c m 2
c 80 cm times 1 in _______ 254 cm
asymp 315 in
60 cm times 1 in _______ 254 cm
asymp 236 in
The dimensions of the painting are approximately
315 in by 236 in
d 315 in times 236 in asymp 743 i n 2
7 120 ft times 1 unit _____ 5 ft
= 24 units
75 ft times 1 unit _____ 5 ft
= 15 units
The dimensions of the drawing are 24 units by
15 units
8 Sample answer 2 in6 ft 1 in3 ft and 1 in1 yd
9 Because the scale is 10 cm1 mm and because
10 cm is longer than 1 mm the drawing will be
larger
10 a Let r represent the scale
54 ft times r = 810 m
r = 810 m ______ 54 ft
r = 150 m ______ 1 ft
The scale is 1 ft = 150 m
b 54 ft times 12 in _____ 1 ft
= 648 in
Let b represent the number of tiny bricks
b = 648 in times 1 brick ______ 04 in
b = 162 bricks
The model is 162 tiny bricks tall
11 a Let h represent the height of the model
h = 30 ft times 126 cm _______ 1 ft
h = 378 cm
Let n represent the number of toothpicks
n = 378 cm times 1 toothpick
_________ 63 cm
n = 6 toothpicks
The model will be 6 toothpicks tall
b 378 cm times 1 swab ______ 76 cm
asymp 5 swabs
The model will be about 5 cotton swabs tall
Focus on Higher Order Thinking
12 If the area of the scale drawing is 100 square cm
then one side is 10 cm Let s represent the side
length of the actual floor
s = 10 cm times 2 ft _____ 1 cm
s = 20 ft
So the area is 20 ft(20 ft) = 400 ft 2
The ratio of areas is 100 square cm 400 square feet
or 1 square cm 4 square feet
Copyright copy by Houghton Mifflin Harcourt 53 All rights reserved
13 Decide on the new scale yoursquod like to use Then find
the ratio between the old scale and the new scale
and redraw the scale drawing accordingly For
example the ratio could be 13 In that case you
would redraw the dimensions at three times the
original size
14 Sample answer 1 __ 4 in 8 ft 40 ft by 24 feet 960 f t
2
LESSON 82
Guided Practice
1 The two angles 45deg and a right angle or 90deg with
the included side 8 cm determine the point at which
the sides meet so a unique triangle is formed
2 The sum of the measures of the two short sides
4 + 3 = 7 The sum is less than the measure of the
long side 11 so no triangle is formed
3 The two angles 40deg and 30deg with the included side
7 cm determine the point at which the sides meet
so a unique triangle is formed
4 The sum of the measures of the two short sides
6 + 7 = 13 The sum is greater than the measure of
the long side 12 so a unique triangle is formed
5 Sample answer Segments with lengths of 5 in
5 in and 100 in could not be used to form a
triangle
Independent Practice
6 A figure with side lengths of 3 centimeters and 6
centimeters and an included angle of 120deg deter-
mine the length of the third side of a triangle and so
produce a unique triangle
6 cm
3 cm120˚
7 The side lengths proposed are 15 ft 21 ft and 37 ft
The sum of the measures of the two shorter sides
15 + 21 = 36 So the sum is less than the measure
of the long side 37 No such triangle can be created
8 The three angle measures can be used to form
more than one triangle The sign and the scale
drawing are two different-sized triangles with the
same angle measures
Focus on Higher Order Thinking
9 More than one triangle can be formed Two triangles
can be created by connecting the top of the 2-in
segment with the dashed line once in each spot
where the arc intersects the dashed line The
triangles are different but both have side lengths of
2 in and 1 1 __ 2 in and a 45deg angle not included
between them
10 The third side has a length of 15 in The third side
must be congruent to one of the other two sides
because the triangle is isosceles The third side
cannot measure 6 in because 6 + 6 is not greater
than 15 So the third side must measure 15 in
LESSON 83
Guided Practice
1 triangle or equilateral triangle
2 rectangle
3 triangle
4 rainbow-shaped curve
5 Sample answer Draw the figure and the plane
Independent Practice
6 Sample answer A horizontal plane results in cross
section that is a circle A plane slanted between
horizontal and vertical results in an oval cross
section A vertical plane through the cylinder results
in a rectangle A vertical plane along an edge of the
cylinder results in a line cross section
7 You would see circles or ovals with a cone but not
with a pyramid or prism
Focus on Higher Order Thinking
8 The plane would pass through the cube on a
diagonal from the top to the bottom of the cube
9 a It is a circle with a radius of 12 in
b The cross sections will still be circles but their
radii will decrease as the plane moves away from
the spherersquos center
10 The dimensions of two faces are 12 in by 8 in two
are 8 in by 5 in and two are 12 in by 5 in the
volume is 480 in 3
11 Sample answer If you think of a building shaped like
a rectangular prism you can think of horizontal
planes slicing the prism to form the different floors
Copyright copy by Houghton Mifflin Harcourt 54 All rights reserved
LESSON 84
Your Turn
5 Supplementary angles sum to 180deg Sample answer angFGA and angAGC
6 Vertical angles are opposite angles formed by two
intersecting lines
Sample answer angFGE and angBGC
7 Adjacent angles are angles that share a vertex and
one side but do not overlap Sample answer
mangFGD and mangDGC
8 Complementary angles are two angles whose
measures have a sum of 90deg Sample answer
mangBGC and mangCGD
9 Because mangFGE = 35deg and angFGE and angBGC are
vertical angles that means mangBGC = 35deg also
Because lines _
BE and _
AD intersect at right angles
mangBGD = 90deg so mangBGC + mangCGD = 90deg which means
mangBGC + mangCGD = 90deg 35deg + x = 90deg 35deg minus 35deg + x = 90deg minus 35deg x = 55deg
mangCGD = 55deg
10 angJML and angLMN are supplementary so their
measures sum to 180deg mangJML + mangLMN = 180deg 3x + 54deg = 180deg 3x + 54deg - 54deg = 180deg - 54deg 3x = 126deg
3x ___ 3 = 126deg ____
3
x = 42deg
mangJML = 3x = 3 ( 42deg ) = 126deg
11 Sample answer You can stop at the solution step
where you find the value of 3x because the measure
of angJML is equal to 3x
Guided Practice
1 angUWV and angUWZ are complementary angles
2 angUWV and angVWX are adjacent angles
3 angAGB and angDGE are vertical angles
so mangDGE = 30deg
4 mangCGD + mangDGE + mangEGF = 180deg 50deg + 30deg + 2x = 180deg 80deg + 2x = 180deg 2x = 100deg mangEFG = 2x = 100deg
5 mangMNQ + mangQNP = 90deg 3x - 13deg + 58deg = 90deg so 3x + 45deg = 90degThen 3x = 45deg and x = 15deg mangMNQ = 3x - 13deg = 3 ( 15deg ) - 13deg = 45deg - 13deg = 32deg
6 Sample answer Let mangS = x Write and solve an
equation ( x + 3x = 180deg ) to find x then multiply the
value by 3
Independent Practice
7 Sample answer angSUR and angQUR are adjacent
They share a vertex and a side
8 Sample answer angSUR and angQUP
9 Sample answer angTUS and angQUN
10 mangQUR = 139deg Sample answer angSUR and angSUP
are supplementary so mangSUP = 180deg - 41deg = 139deg angSUP and angQUR are vertical angles so they are
congruent and mangQUR = mangSUP = 139deg
11 mangRUQ is greater Sample answer angSUR and
angNUR are complementary so
mangNUR = 90deg - 41deg = 49deg mangTUR = 41deg + 90deg which is less than
mangRUQ = 49deg + 90deg
12 Because angKMI and angHMG are vertical angles their
measures are equal
mangKMI = mangHMG
84 = 4x
84 ___ 4 = 4x ___
4
x = 21deg
13 Because angKMH and angKMI are supplementary
angles the sum of their measures is 180deg mangKMH + mangKMI = 180deg x + 84 = 180
x + 84 - 84 = 180 - 84
x = 96
mangKMH = 96deg
14 Because angCBE and angEBF are supplementary
angles the sum of their measures is 180deg mangCBE + mangEBF = 180deg x + 62 = 180
x + 62 - 62 = 180 - 62
x = 118
mangCBE = 118deg
15 Because angABF and angFBE are complementary
angles the sum of their measures is 90deg mangABF + mangFBE = 90deg x + 62 = 90
x + 62 - 62 = 90 - 62
x = 28
mangABF = 28deg
16 Because angCBA and angABF are supplementary
angles the sum of their measures is 180deg mangABF = 28deg so
mangCBA + mangABF = 180deg x + 28 = 180 - 28
x + 28 - 28 = 152
mangCBA = 152deg
Copyright copy by Houghton Mifflin Harcourt 55 All rights reserved
17 If the two angles are complementary the sum of
their angles is 90degmangA + mangB = 90deg ( x + 4deg ) + x = 90deg 2x + 4deg = 90deg _ -4deg _ -4deg 2x = 86deg
2x ___ 2 = 86deg ___
2
x = 43degBecause x = mangB then mangB = 43deg and
mangA = 43deg + 4deg so mangA = 47deg
18 If the two angles are supplementary the sum of their
angles is 180degmangD + mangE = 180deg 5x + x = 180deg 6x = 180deg
6x ___ 6 = 180deg ____
6
x = 30degBecause x = mangE then mangE = 30deg and
mangD = 30deg x 5 so mangD = 150deg
19 If the two angles are complementary the sum of
their angles is 90deg When angles are divided into
minutes and seconds one apostrophe signifies a
minute and two apostrophes signifies a second
mangJ + mangK = 90deg0000
48deg268+ mangK = 90deg0000
_ -48deg268 _ -48deg268
mangK = 41deg3352
mangK = 41deg3352 or mangK = 41 degrees
33 minutes 52 seconds
Focus on Higher Order Thinking
20 Yes a parking lot can be built because the measure
of angle K is 180deg - ( 50deg + 90deg ) or 40deg which is
greater than 38deg
21 Disagree the sum of the measures of a pair of
complementary angles is 90deg So the measure of
each angle must be less than 90deg 119deg gt 90deg
22 a The sum of mangA and its complement will be 90deg Let x represent the complement
mangA + x = 90deg 77deg + x = 90deg _ -77deg = _ -77deg x = 13deg The complement of mangA has a measure of 13deg
and a complement of a complement of mangA
would have an angle equal to mangA or 77deg b A complement of a complement of an angle has
the same measure of the angle itself Let xdeg be
the measure of an angle The measure of a
complement of the angle is ( 90 - xdeg ) A complement of that angle has a measure of
( 90 - ( 90 - xdeg ) ) = ( 90 - 90 + xdeg ) = xdeg
MODULE 8
Ready to Go On
1
Living
roomKitchen Office Bedroom Bedroom Bathroom
Actual
ℓ times w ( ft ) 16 times 20 12 times 12 8 times 12 20 times 12 12 times 12 6 times 8
Blueprint
ℓ times w ( in ) 4 times 5 3 times 3 2 times 3 5 times 3 3 times 3 15 times 2
2 No The side lengths proposed are 8 cm 4 cm and
12 cm The sum of the measures of the two shorter
sides 4 + 8 = 12 So no such triangle can be
created
3 The longest side could be 15 cm because 20 cm is
too long given the lengths of the other sides
4 A circle is a possible cross section of a sphere
A point is another
5 A circle rectangle oval and line are possible cross
sections of a cylinder
6 mangBGC and mangFGE are vertical angles so
mangFGE = 50deg
7 If the two angles are complementary the sum of
their angles is 90deg mangS + mangY = 90deg
( 2 ( mangY ) - 30deg ) + mangY = 90deg 3 ( mangY ) - 30deg = 90deg _ +30deg = _ +30deg 3 ( mangY ) = 120deg
3 ( mangY ) ________ 3 = 120deg ____
3
mangY = 40deg
mangY = 40deg
8 Sample answer You can use scale drawings to plan
rooms or gardens
Copyright copy by Houghton Mifflin Harcourt 56 All rights reserved
MODULE 9 Circumference Area and Volume
Are You Ready
1 416
_ times 13
1248
_ +thinsp4160
5408
5408
2 647
_ times thinsp04
2588
2588
3 705
_ times thinsp94
2820
_ +thinsp63450
66270
6627
4 256
_ timesthinsp049
2304
_ +thinsp10240
12544
12544
5 1 __ 2 ( 14 ) ( 10 )
7 ( 10 )
70 i n 2
6 ( 35 ) ( 35 )
1225 ft 2
7 ( 8 1 __ 2 ) ( 6 )
17 ___ 1 2 sdot 6 3 __
1
51 i n 2
8 1 __ 2 ( 125 ) ( 24 )
1 __ 2 ( 24 ) ( 125 )
( 12 ) ( 125 )
15 m 2
LESSON 91
Your Turn
3 d = 11 cm
C = πd
C asymp 314 ( 11 )
C asymp 3454
The circumference is about 3454 cm
6 C = πd
44 asymp 314d
44 ____ 314
asymp d
d asymp 1401 yards
Divide the diameter of the garden by the digging
rate
1401 divide 7 = 2001
It takes Lars about 2 hours to dig across the garden
Guided Practice
1 d = 9 in
C asymp 314 ( 9 )
C asymp 2826 in
2 r = 7 cm
C = 2πr
C asymp 2 ( 22 ___ 7 ) ( 7 )
C asymp 44 cm
3 d = 25 m
C = πd
C asymp 314 ( 25 )
C asymp 785 m
4 r = 48 yd
C = 2πr
C asymp 2 ( 314 ) ( 48 )
C asymp 3014 yd
5 r = 75 in
C = 2πr
C asymp 2 ( 314 ) ( 75 )
C asymp 471 in
6 Find the diameter
C = πd
66 asymp 314d
66 ____ 314
asymp 314d _____ 314
21 asymp d
Find the cost
Carlos needs 21 + 4 = 25 feet of rope
25 times $045 = $1125
Carlos will pay $1125 for the rope
7 Because C = π yd and C = πd d = 1 yd then
r = 05 yd
d = 1 yd
8 Because C = 788 ft and C = 2πr
2πr = 788
2πr ___ 2π
= 788 ____ 2π
r asymp 788 _______ 2 ( 314 )
r asymp 1255 ft
d = 2r asymp 2 ( 1255 ft )
d asymp 2510 ft
9 d = 2r so r = d __ 2 asymp 34 ___
2
r asymp 17 in
C = πd asymp 314 ( 34 )
C = 1068 in
Copyright copy by Houghton Mifflin Harcourt 57 All rights reserved
10 Use the formula C = πd and substitute
314 for π and 13 for the diameter
Independent Practice
11 d = 59 ft
C = πd
C asymp 314 ( 59 )
C asymp 1853 ft
12 r = 56 cm
C = 2πr
C asymp 2 ( 22 ___ 7 ) ( 56 )
C asymp 352 cm
13 d = 35 in
C = πd
C asymp ( 22 ___ 7 ) ( 35 )
C asymp 110 in
14 Sample answer In exercises 12 and 13 the radius
or diameter is a multiple of 7
15 r = 94 ft
d = 2r = 2 ( 94 )
d = 188 ft
C = πd
C asymp 314 ( 188 )
C asymp 590 ft
16 d = 475 in
r = d __ 2 = 475 ____
2
r = 2375 in
C = πd
C asymp 314 ( 475 )
C asymp 14915 in
17 d = 18 in
r = d __ 2 = 18 ___
2
r = 9 in
C = πd
C asymp 314 ( 18 )
C asymp 5652 in
18 r = 15 ft
C = 2πr
C asymp 2 ( 314 ) ( 15 ) = 942 ft
The cost for edging is C times $075 per foot
so ( 942 ) ( 075 ) = 7065 or about $707
19 C = πd
C asymp ( 22 ___ 7 ) ( 63 )
C asymp 198 ft
The distance traveled is 12 times the
circumference of the Ferris wheel so
distance = 12 ( 198 ) or about 2376 ft
20 C = πd asymp 314 ( 2 )
C asymp 628 ft
Converting km to ft
2 km sdot ( 3280 ft _______
1 km ) = 6560 ft
6560 ft
_______ 628 ft
= 104459
The wheel makes about 1045 revolutions
21 The distance your friend walks is half the
circumference of the pond
1 __ 2 C = 1 __
2 πd asymp 1 __
2 sdot 314 ( 025 ) = 03925
Your friend walks approximately 03925 mi
The difference is 03925 - 025 = 01425
Your friend walks about 014 mi farther
22 Capitol Rotunda Dimensions
Height 180 ft
Circumference 3015 ft
Radius r = C ___ 2π asymp 3015
_______ 2 ( 314 )
asymp 48 ft
Diameter d = 2r = 2 ( 48 ) = 96 ft
Focus on Higher Order Thinking
23 The length of the fence is half the circumference
plus the diameter
1 __ 2 C = 1 __
2 πd asymp 1 __
2 sdot 314 ( 30 ) = 471
The total distance is 471 + 30 = 771 ft
The total cost is the length of fence times the cost
per linear foot
( 771 ft ) ( $925 _____
ft ) = $71318
It will cost about $71318
24 The circumference of the patio is
C = πd asymp 314 ( 18 ) = 5652 ft
Converting the length of one strand of lights from
inches to feet
( 54 in ) ( 1 ft _____ 12 in
) = 45 ft
To find the number of strands of lights divide the
circumference by the length of one strand
5652 ft _______ 45 ft
= 1256
Because Sam cannot buy a fraction of a strand he
must buy 13 strands
25 The distance is the difference in the circumferences
C inner
= πd asymp 314 ( 150 ) = 471 ft
The outer diameter is 150 ft + 2 ( 2 ft ) = 154 ft
C outer
= πd asymp 314 ( 154 ) = 48356 ft
The difference is 48356 - 471 = 1256 ft
It is about 1256 ft farther
26 No The circumference of the larger gear is about
πd asymp 314 ( 4 ) = 1256 inches The circumference of
the smaller gear is about πd asymp 314 ( 2 ) = 628
inches So the circumference of the larger gear is
628 inches more than the circumference of the
smaller gear
Copyright copy by Houghton Mifflin Harcourt 58 All rights reserved
27 Pool B about 057 m or 184 ft Sample answer
24 feet asymp 732 m so the diameter of Pool B is
greater and the circumference is greater
314 ( 75 ) - 314 ( 732 ) = 314 ( 018 ) asymp 057
057 m asymp 187 ft
LESSON 92
Your Turn
4 A = π r 2 A = π ( 10 ) 2
A asymp 314 ( 10 ) 2
A asymp 314 sdot 100
A asymp 314 f t 2
Guided Practice
1 r = d __ 2 = 14 ___
2 = 7 m
A = π r 2 A = π ( 7 ) 2
A asymp 314 ( 7 ) 2
A asymp 314 sdot 49
A asymp 1539 m 2
2 A = π r 2 A = π ( 12 ) 2
A asymp 314 ( 12 ) 2
A asymp 314 sdot 144
A asymp 4522 m m 2
3 r = d __ 2 = 20 ___
2 = 10 yd
A = π r 2 A = π ( 10 ) 2
A asymp 314 ( 10 ) 2
A asymp 314 sdot 100
A asymp 314 y d 2
4 A = π r 2 A = π ( 8 ) 2
A asymp 314 ( 8 ) 2
A asymp 314 sdot 64
A asymp 20096 i n 2
5 r = d __ 2 = 12 ___
2 = 6 cm
A = π r 2 A = π ( 6 ) 2
A asymp 314 ( 6 ) 2
A asymp 314 sdot 36
A asymp 11304 c m 2
6 r = d __ 2 = 13 ___
2 = 65 in
A = π r 2 A = π ( 65 ) 2
A asymp 314 ( 65 ) 2
A asymp 314 sdot 4225
A asymp 13267 i n 2
7 C = 4π = 2πr
4π ___ 2π
= 2πr ___ 2π
r = 2
A = π r 2 A = π ( 2 ) 2
A = 4π square units
8 C = 12π = 2πr
12π ____ 2π
= 2πr ___ 2π
r = 6
A = π r 2 A = π ( 6 ) 2
A = 36π square units
9 C = π __ 2 = 2πr
π __ 2 divide 2π = 2πr ___
2π
π __ 2 sdot 1 ___
2π = r
1 __ 4 = r
A = π r 2
A = π ( 1 __ 4 ) 2 = π ( 1 ___
16 )
A = π ___ 16
square units
10 A = π r 2 = 64π
π r 2 ___ π = 64π ____ π
r 2 = 64
r = 8
C = 2πr
= 2π ( 8 )
=16π yd
11 A = π r 2
Independent Practice
12 r = d __ 2 = 10 ___
2 = 5 in
A = π r 2 A = π ( 5 ) 2
A asymp 314 ( 5 ) 2
A asymp 314 sdot 25
A asymp 785 i n 2
13 A = π r 2 A = π ( 16 ) 2
A asymp 314 ( 16 ) 2
A asymp 314 sdot 256
A asymp 80384 c m 2
14 The area of the window is half the area of a circle of
diameter 36 in
r = d __ 2 = 36 ___
2 = 18 in
A semicircle
= 1 __ 2 π r 2
A semicircle
= 1 __ 2 π ( 18 ) 2
A semicircle
asymp 1 __ 2 ( 314 ) ( 18 ) 2
A semicircle
asymp 05 sdot 314 sdot 324
A asymp 50868 i n 2
Copyright copy by Houghton Mifflin Harcourt 59 All rights reserved
15 If the point ( 3 0 ) lies on the circle and the origin is
its center the radius of the circle is 3 units
A = π r 2 A = π ( 3 ) 2
A asymp 314 ( 3 ) 2
A asymp 314 sdot 9A asymp 2826 square units
16 The difference in areas is given by
A r = 75 mi
- A r = 50 mi
π ( 75 ) 2 - π ( 50 ) 2
= π ( 7 5 2 minus 5 0 2 ) = π ( 5625 minus 2500 ) = π ( 3125 ) asymp 98125
The area of the relayed signal is about 9813 mi 2
greater
17 The area of the field which is not reached by the
sprinkler is the area of the field minus the area
reached by the sprinkler or s 2 minus π r 2 where
s = 12 m and r is the radius of the circular area The
diameter of the circle is equal to a side of the field
12 m so the radius is 12 ___ 2 = 6 m So
s 2 minus π r 2 = 1 2 2 minus π ( 6 ) 2
= 144 minus π ( 36 )
asymp 144 minus 11304 = 3096
The area not reached by the sprinkler is
approximately 3096 m 2
18 No the area of the regular pancake is 4π in 2 and the
area of the silver dollar pancake is π in 2 so the area
of the regular pancake is 4 times the area of the
silver dollar pancake
19 No the top of the large cake has an area 9 times
that of the small cake The area of the top of the
large cake is 144π in 2 and that of the small cake is
16π in 2
20 Sample answer First find the radius of the circle by
using the formula C = 2πr Then substitute the
radius into the formula for the area of a circle
21 The 18-inch pizza is a better deal because it costs
about $20
_____ π ( 9 ) 2
asymp $008 or 8 cents per square inch
while the 12-inch pizza costs about $10
_____ π ( 6 ) 2
asymp $009
or 9 cents per square inch
22 a Because the bear can walk at a rate of 2 miles
per hour and was last seen 4 hours ago the
radius of the area where the bear could be found
is given by ( 2 miles per hour ) ( 4 hours ) = 8 miles
A = π r 2 = π ( 8 ) 2
= π ( 64 )
asymp 20096
The searchers must cover an area of about
201 mi 2
b The additional area is the difference in areas of
circles with radii ( 2 miles per hour ) ( 5 hours )
= 10 miles and the original 8 miles
A new
minus A old
= π ( 10 ) 2 - π ( 8 ) 2
= π ( 1 0 2 - 8 2 ) = π ( 100 - 64 )
= π ( 36 ) asymp 11304
The searchers would have to cover about 113 mi 2
more area
Focus on Higher Order Thinking
23 No the combined area is 2π r 2 while the area of a
circle with twice the radius is 4π r 2
24 The area is multiplied by a factor of n 2
25 To find the part that is the bullrsquos-eye take the ratio of
the area of the bullrsquos-eye to that of the whole target
The radius of the bullrsquos-eye is 3 __ 2 = 15 in and
the radius of the whole target is 15 ___ 2 = 75 in
A
bullrsquos-eye ________
A whole target
=
π ( 15 ) 2 ______
π ( 75 ) 2
= ( 15 ) 2
_____ ( 75 ) 2
= 225 _____ 5625
= 004
The bullrsquos-eye is 004 or 4 of the whole target
LESSON 93
Your Turn
2 The figure can be separated into a rectangle and
two right triangles
The dimensions of the large rectangle are
length = 8 + 3 = 11 ft width = 4 ft
The dimensions of the two small triangles are
base = 3 ft height = 2 ft ( upper triangle ) base = 3 ft height = 3 ft ( lower triangle ) The area of the rectangle is
A = ℓw = 11 sdot 4 = 44 f t 2
The area of the upper triangle is
A = 1 __ 2 bh = 1 __
2 sdot 3 sdot 2 = 3 f t 2
The area of the lower triangle is
A = 1 __ 2 bh = 1 __
2 sdot 3 sdot 3 = 45 f t 2
Therefore the total area of the figure is
44 + 3 + 45 = 515 f t 2
3 The figure can be separated into a square and a
semicircle
Each side of the square is equal to 10 m
The radius of the semicircle is half the diameter
or 10 ___ 2 = 5 m
The area of the square is
A = s 2 = 1 0 2 = 100 m 2
The area of the semicircle is
A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 5 ) 2
A asymp 1 __ 2 sdot 314 sdot 25
A asymp 3925 m 2
Therefore the approximate total area of the figure is
100 + 3925 = 13925 m 2
Copyright copy by Houghton Mifflin Harcourt 60 All rights reserved
4 The composite figure is made up of a rectangle and two
semicircles which can be combined to form one circle
The dimensions of the rectangle are
length = 5 ft width = 4 ft
The diameter of the circle is 4 ft so the radius is
4 __ 2 = 2 ft
The area of the rectangle is
A = ℓw = 5 sdot 4 = 20 f t 2
The area of the circle is
A = π r 2 A asymp 314 sdot ( 2 ) 2
A asymp 314 sdot 4A asymp 1256 f t 2
The approximate total area is the sum of these
two areas
20 + 1256 = 3256 f t 2
Because the glass costs $28 per square foot
multiply the total area by the cost per square foot
( 3256 f t 2 ) ( $28 ____
f t 2 ) = $91168
It will cost about $91168 to replace the glass
Guided Practice
1 Separate the figure into a triangle a rectangle and
a parallelogram
Find the area of each figure
For triangle A = 1 __ 2 bh = 1 __
2 ( 4 ) ( 2 ) = 4
For rectangle A = ℓw = ( 5 ) ( 3 ) = 15
For parallelogram A = bh = ( 5 ) ( 3 ) = 15
Triangle 4 cm 2 rectangle 15 cm
2 parallelogram
15 cm 2
Step 3 Find the area of the composite figure
4 + 15 + 15 = 34 cm 2
The area of the irregular shape is 34 cm 2
2 Method 1
A 1 = ℓw A
2 = ℓw
= 12 sdot 9 = 20 sdot 9 = 108 = 180
Total area = 288 c m 2
Method 2
A 1 = ℓw A
2 = ℓw
= 9 sdot 8 = 12 sdot 8 = 72 = 216
Total area = 288 c m 2
3 Separate the figure into a trapezoid with h = 5 ft
b 1 = 7 ft and b 2 = 4 ft and a parallelogram with
base = 4 ft and height = 4 ft
For trapezoid A = 1 __ 2 h ( b
1 + b
2 )
A = 1 __ 2 ( 5 ) ( 7 + 4 )
A = 1 __ 2 ( 5 ) ( 11 ) = 275 f t 2
For parallelogram A = bh = ( 4 ) ( 4 ) = 16 f t 2
Find the area of the composite figure
275 + 16 = 435 ft 2
Multiply the total area by the cost per square foot to
find the cost
( 435 f t 2 ) ( $225 _____
f t 2 ) = $9788
4 The first step is separating the composite figure into
simpler figures
Independent Practice
5 Area of square A = s 2 = 2 6 2 = 676 i n 2
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 13 ) 2
A asymp 1 __ 2 sdot 314 sdot 169
A asymp 26533 i n 2
The approximate total area is the sum
676 + 26533 = 94133 in 2
6 a The floor of the closet is a composite of a
rectangle with length = 10 ft and width = 4 ft and
a triangle with base = 6 ft and height = 3 + 4 = 7 ft
Area of rectangle A = ℓw = 10 sdot 4 = 40 f t 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 6 sdot 7
A = 1 __ 2 sdot 42
A = 21 f t 2
The total area is the sum
40 + 21 = 61 f t 2
b The cost is the area multiplied by the cost per
square foot
( 61 f t 2 ) ( $250 _____
f t 2 ) = $15250
7
O 42-2-4
2
-4
y
A (-2 4) B (0 4)
C (2 1)D (5 1)
E (5 -2)F (-2 -2)
The area can be thought of as a composite of a
trapezoid and a rectangle
For trapezoid Let b 1 of the trapezoid be the
segment from the point ( -2 1 ) point C with length
4 units b 2 be from point A to point B with length
2 units and height equal to 3 units
For rectangle The corners of the rectangle are
( -2 1 ) D E and F Let the length of the rectangle
be 7 units and the width be 3 units
Area of trapezoid
A = 1 __ 2 h ( b
1 + b
2 )
A = 1 __ 2 ( 3 ) ( 4 + 2 )
A = 1 __ 2 ( 3 ) ( 6 ) = 9 square units
Copyright copy by Houghton Mifflin Harcourt 61 All rights reserved
Area of rectangle A = ℓw
A = 7 sdot 3 A = 21 square units
The total area is the sum
9 + 21 = 30 square units
8 The field is a composite of a square with side = 8 m
a triangle with base = 8 m and height = 8 m and a
quarter of a circle with radius = 8 m
Area of square A = s 2 = 8 2 = 64 m 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 8 sdot 8
A = 1 __ 2 sdot 64
A = 32 m 2
Area of quarter circle A = 1 __ 4 π r 2
A asymp 1 __ 4 sdot 314 sdot ( 8 ) 2
A asymp 1 __ 4 sdot 314 sdot 64
A asymp 5024 f t 2
The approximate total area is the sum
64 + 32 + 5024 = 14624 m 2
9 The bookmark is a composite of a rectangle with
length = 12 cm and width = 4 cm and two
semicircles which combine to form a full circle with
diameter = 4 cm so radius = 4 __ 2 = 2 cm
Area of rectangle A = ℓw = 12 sdot 4 = 48 c m 2
Area of circle A = π r 2 A asymp 314 sdot ( 2 ) 2
A asymp 314 sdot 4 A asymp 1256 c m 2
The approximate total area is the sum
48 + 1256 = 6056 cm 2
10 The pennant is a composite of a rectangle with
length = 3 ft and width = 1 ft and a triangle with
base = 1 ft and height = 1 ft
Area of rectangle A = ℓw = 3 sdot 1 = 3 f t 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 1 sdot 1
A = 1 __ 2 sdot 1
A = 05 f t 2
The area of one pennant is the sum
3 + 05 = 35 ft 2
Alex is making 12 pennants so the total area of all
12 pennants is 12 sdot 35 = 42 ft 2
The cost for the pennants will be the total area times
the fabric cost per square foot
( 42 f t 2 ) ( $125 _____
f t 2 ) = $5250
11 The area of the square is the total area minus the
area of triangle
325 ft 2 - 75 ft 2 = 25 ft 2
The area of a square is A = s 2 so s 2 = 25 f t 2
Because 5 sdot 5 = 25 the length of each side of the
square is 5 ft
Focus on Higher Order Thinking
12 The area of the garden can be found from counting
squares there are 18 full squares and 4 half-squares
for a total of 20 square units Each square unit will
grow about 15 carrots So Christina will grow about
20 ( 15 ) or 300 carrots
13 To find the length of the three sides of the square
subtract the lengths of the two sides of the triangle
from the perimeter The total length of three sides of
the square is 56 - 20 = 36 in Divide by 3 to find
that the length of one side and the base of the
triangle is equal to 12 in The total area of the figure
is the area of the square plus the area of the
triangle
Area of square A = s 2 = 1 2 2 = 144 i n 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 12 sdot 8
A = 1 __ 2 sdot 96
A = 48 i n 2
The total area is the sum
144 + 48 = 192 in 2
14 Think of the scarf as a rectangle minus two
semicircles The rectangle has length = 28 in and
width = 15 in The circle has diameter = 15 in so
its radius is 15 ___ 2 = 75 in
Area of rectangle A = ℓw = 28 sdot 15 = 420 i n 2
Area of circle A = π r 2 A asymp 314 sdot ( 75 ) 2
A asymp 314 sdot 5625
A asymp 176625 i n 2
The total area is the difference
420 - 176625 = 243375 in 2 or 243 3 __
8 i n 2
15 a The window is a composite of a square and a
semicircle Because each square in the window
has an area of 100 in 2 the length of each side is
10 in So each side of the square portion of the
entire window has length 10 sdot 4 = 40 in The
diameter of the semicircle is also 40 in so
the radius is 40 ___ 2 = 20 in
Area of square A = s 2 = 4 0 2 = 1600 i n 2
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 20 ) 2
A asymp 1 __ 2 sdot 314 sdot 400
A asymp 628 i n 2
The approximate total area is the sum
1600 + 628 = 2228 in 2
Copyright copy by Houghton Mifflin Harcourt 62 All rights reserved
b The shade is a composite of a rectangle and
a semicircle The length of the rectangle is equal
to the length of one side of the square portion
of the window plus 2 sdot 4 inches for a total of
40 + 2 sdot 4 = 48 in
The height of the rectangular portion of the shade
is equal to 4 times the length of one side of the
square portion of the window plus 4 inches for a
total of 40 + 4 = 44 in
The diameter of the semicircle at the top is the
same as the length of the bottom of the shade
48 in so the radius = 48 ___ 2 = 24 in
Area of rectangle A = ℓw = 48 sdot 44 = 2112 i n 2
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 24 ) 2
A asymp 1 __ 2 sdot 314 sdot 576
A asymp 90432 i n 2
The approximate total area of the shade is
the sum
2112 + 90432 asymp 3016 in 2
LESSON 94
Your Turn
3 Find the area of a base
B = l times w
= 9 times 2
= 18 square inches
Find the perimeter of the base
P = 2 ( 9 ) + 2 ( 2 )
= 18 + 4 = 22 inches
Find the surface area
S = Ph + 2B
S = 22 ( 1 1 __ 2 ) + 2 ( 18 )
= 33 + 36
= 69
The surface area of the box is 69 square inches
4 Find the area of the base of the larger prism
B = times w
= 12 times 12
= 144 square inches
Find the perimeter of the base
P = 4 ( 12 )
= 48 inches
Find the surface area of the larger prism
S = Ph + 2B
S = 48 ( 12 ) + 2 ( 144 )
= 576 + 288
= 864 square inches
Find the area of the base of the smaller prism
B = l times w
= 8 times 8
= 64 square inches
Find the perimeter of the base
P = 4 ( 8 )
= 32 inches
Find the surface area of the smaller prism
S = Ph + 2B
S = 32 ( 8 ) + 2 ( 64 )
= 256 + 128
= 384 square inches
Add the surface areas of the two prisms and
subtract the areas not stained (the bottom of the
larger prism and the smaller prism and an equal
area of the top of the larger prism where the smaller
prism sits) Surface area = 864 + 384 - 144 - 64
- 64 = 976 The surface area of the part of the plant
stand that she will stain is 976 square inches
Guided Practice
1 Perimeter of base = 5 + 5 + 8 = 18
Perimeter of base = 18 ft
Height = 7 ft
Base area = 1 __ 2 ( 3 ) ( 8 ) = 12 ft 2
Surface area
S = ( 18 ft ) ( 7 ft ) + 2 ( 12 ft 2 ) = 150 ft 2
2 Find the area of a base of the cube
B = l times w
= 25 times 25
= 625 m 2
Find the perimeter of the base of the cube
P = 4 ( 25 )
= 10 m
Find the surface area of the cube
S = Ph + 2B
S = 10 ( 25 ) + 2 ( 625 )
= 25 + 125
= 375
Surface area of cube
S = 375 m 2
Find the area of a base of the rectangular prism
B = l times w
= 11 times 9
= 99 m 2
Find the perimeter of the base of the rectangular
prism
P = 2 ( 11 ) + 2 ( 9 )
= 22 + 18
= 40 m
Find the surface area of the rectangular prism
S = Ph + 2B
S = 40 ( 7 ) + 2 ( 99 )
= 280 + 198
= 478
Surface area of rectangular prism
S = 478 m 2
Find the overlapping area the bottom of the cube
A = ( 25 ) ( 25 ) = 625
Overlapping area A = 625 m 2
Surface area of composite figure
= 375 + 478 -2 ( 625 ) = 503 m 2
3 Find the surface area of each of the prisms that
make up the solid Add the surface areas and
subtract the areas of any parts that are not on the
surface
Copyright copy by Houghton Mifflin Harcourt 63 All rights reserved
Independent Practice
4 Find the area of a base
B = l times w
= 10 times 3
= 30 in 2
Find the perimeter of the base
P = 2 ( 10 ) + 2 ( 3 )
= 20 + 6
= 26 in
Find the surface area
S = Ph + 2B
S = 26 ( 4 ) + 2 ( 30 )
=104 + 60
= 164 in 2
She needs 164 in 2 of wrapping paper
5 Find the area of the base
B = l times w
= 20 times 15
= 300 cm 2
Find the perimeter of the base
P = 2 ( 20 ) + 2 ( 15 )
= 40 + 30
= 70 cm
Find the surface area of the box
S = Ph + 2B
S = 70 ( 9 ) + 2 ( 300 )
= 630 + 600
= 1230 cm 2
Find the surface area of the top and sides
1230 - 300 = 930 cm 2
Find the area of a glass tile
Area of tile = 5 times 5 = 25 mm 2
Convert cm 2 to mm
2
930 cm 2 times 100 mm
2 ________
1 cm 2 = 93000 mm
2
Find the number of tiles needed
93000 divide 25 = 3720
3720 tiles are needed
6 Find the area of the L-shaped base
Area of L-shape = 2 times 1 + 3 times 1
= 2 + 3 = 5 in 2
Find the perimeter of the L-shaped base
Perimeter = 3 + 3 + 1 + 2 + 2 + 1
= 12 in
Find the surface area
S = Ph + 2B
S = 12 ( 3 ) + 2 ( 5 )
= 36 + 10
= 46 in 2
The surface area of each brace is 46 in 2
7 Find the area of the triangular prism
Perimeter = 25 + 25 + 3 = 8 ft
Base area = 1 __ 2 ( 2 ) ( 3 ) = 3 ft 2
Surface area = Ph + 2B
= 8 ( 4 ) + 2 ( 3 )
= 32 + 6 = 38 ft 2
Find the area of the rectangular prism
Perimeter = 2 ( 3 ) + 2 ( 4 ) = 14 ft
Base area = 3 times 4 = 12 ft 2
Surface area = Ph + 2B
= 14 ( 2 ) + 2 ( 12 )
= 28 + 24 = 52 ft 2
Add the surface areas of the two prisms and
subtract the parts not on the surface
Surface area = 38 + 52 - 12 - 12 = 66 ft 2
The total surface area of the doghouse is 66 ft 2
8 Treat the figure as ( 1 ) a composite of two triangular
prisms and one rectangular prism or ( 2 ) a prism
with a base that is a trapezoid
9 Find the area of the trapezoid base
Area of trapezoid = 1 __ 2 ( b
1 + b
2 ) h
1 __ 2 ( 16 + 48 ) 12 = 384 in
2
Find the perimeter of the base
P = 48 + 20 + 16 + 20 = 104 in
Find the surface area
S = Ph + 2B
S = 104 ( 24 ) + 2 ( 384 )
= 2496 + 768
= 3264 in 2
The surface area of the ramp is 3264 in 2
10 Find the area of the base of the larger prism
B = l times w
= 7 times l
= 7 ft 2
Find the perimeter of the base
P = 2 ( 7 ) + 2 ( 1 )
= 14 + 2
= 16 ft
Find the surface area of the larger prism
S = Ph + 2B
S = 16 ( 2 ) + 2 ( 7 )
= 32 + 14
= 46 f t 2
Find the area of the base of the smaller prism
B = l times w
= 1 times 1
= 1 ft 2
Find the perimeter of the base
P = 2 ( 1 ) + 2 ( 1 )
= 2 + 2 = 4 ft
Find the surface area of the smaller prism
S = Ph + 2B
S = 4 ( 3 ) + 2 ( 1 )
= 12 + 2
= 14 ft 2
Add the surface areas of the two prisms and
subtract the parts not on the surface
Surface area = 46 + 14 - 1 - 1 = 58 ft 2
The surface area of the stand is 58 ft 2
11 Find the number of cans of paint needed
58 divide 25 = 232
It takes 2 full cans and 1 partial can so 3 cans are
needed
Find the cost of 3 cans of paint
3 times 679 = 2037
No they need 3 cans which will cost $2037
Copyright copy by Houghton Mifflin Harcourt 64 All rights reserved
12 Find the area of the base of the box
B = l times w
= 27 times 24
= 648 cm 2
Find the perimeter of the base
P = 2 ( 27 ) + 2 ( 24 )
= 54 + 48
= 102 cm
Find the surface area of the box
S = Ph + 2B
S = 102 ( 10 ) + 2 ( 648 )
= 1020 + 1296
= 2316 cm 2
2316 cm 2 will be covered with paper
13 Area of the original base B = l times w
Area of the new base = 2l times 2w = 4lw = 4B
Perimeter of the original = 2l + 2w
Perimeter of the new = 2 ( 2l ) + 2 ( 2w ) =
2 ( 2l + 2w ) = 2P
Original S = Ph + 2B
New S = 2Ph + 2 ( 4B )
No Ph doubles and 2B quadruples S more than
doubles
Focus on Higher Order Thinking
14 Find the area of the base of the prism
B = l times w
= 25 times 25
= 625 ft 2
Find the perimeter of the base
P = 4 ( 25 )
= 10 ft
Find the surface area of the prism
S = Ph + 2B
S = 10 ( 35 ) + 2 ( 625 )
= 35 + 135
= 485 ft 2
Find the surface area less the area of the bottom
surface of the prism
485 - 625 = 4225 ft 2
Find what percent of the surface area less the area
of the bottom is compare to the total surface area
4225 _____ 485
times 100 asymp 87
Sample answer She would be painting about 87
of the total surface area so she will use about 87
of the total amount of paint
15
Circumference ofcircle πd = πtimes4
r = 2 in
9 in
Find the area of the circle base
A = πr 2
asymp 31 4 ( 2 ) 2 = 1256 in 2
Find the circumference of the circle
C = πd
asymp 314 ( 4 ) = 1256 in 2
Find the area of the rectangle
Area asymp 9 times 1256 = 11304 in 2
Find the surface area of the cylinder
S = Ch + 2B
asymp 1256 ( 9 ) + 2 ( 1256 ) = 13816 in 2
Round to the nearest tenth 1382 in 2
The surface area of the oatmeal box is
approximately 1382 in 2
Find the amount of cardboard for 1500 boxes
1500 times 1382 = 207300 in 2
Convert square inches to square feet and round to
the nearest whole number
( 207300 in 2 ) 1 ft 2 _______
144 in 2 asymp 1440 ft 2
It would take about 1440 ft 2 of cardboard
16 Each face has 9 squares 1 cm by 1 cm so S =
54 cm 2 The surface area stays the same when one
or more corner cubes are removed ( Fig 2 3 ) because the number of faces showing is still the
same In Fig 4 S increases because 2 more faces
show
LESSON 95
Your Turn
2 Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 24 ) 7
= 84 m 2
Find the volume of the prism
V = Bh
= ( 84 ) ( 22 )
= 1848 m 3
The volume of the prism is 1848 m 3
5 Find the base area B of the trapezoidal prism
B = 1 __ 2 ( b 1 + b 2 ) h
= 1 __ 2 ( 8 + 12 ) 10
= 1 __ 2 ( 20 ) 10 = 100 cm
2
Find the volume of the prism
V = Bh
= ( 100 ) ( 22 )
= 2200 cm 3
The volume of the prism is 2200 cm 3
7 Find the volume of each prism
Find the base area B of the rectangular prism
B = bh
= ( 13 ) 13
= 169 in 2
Find the volume of the rectangular prism
V = Bh
= ( 169 ) ( 30 )
= 5070 in 3
Copyright copy by Houghton Mifflin Harcourt 65 All rights reserved
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 9 ) 13
= 585 in 2
Find the volume of the triangular prism
V = Bh
= ( 585 ) ( 30 )
= 1755 in 3
Find the sum of the volumes
5070 + 1755 = 6825 in 3
The volume of the composite figure is 6825 in 3
Guided Practice
1 B = 1 __ 2 bh = 1 __
2 ( 8 ) ( 3 ) = 12 ft 2
V = Bh = ( 12 times 7 ) ft 3 = 84 ft 3
2 B = 1 __ 2 ( b 1 + b 2 ) h = 1 __
2 ( 15 + 5 ) 3 = 30 m
2
V = Bh = ( 30 times 11 ) m 3 = 330 m 3
3 Find the base area B of the rectangular prism
B = bh
= ( 4 ) 6 = 24 ft 2
Find the volume of the rectangular prism
V = Bh
= ( 24 ) ( 12 ) = 288 ft 3
The volume of the rectangular prism = 288 ft 3
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 6 ) 4 = 12 ft 2
Find the volume of the triangular prism
V = Bh
= ( 12 ) ( 6 ) = 72 ft 3
The volume of the triangular prism = 72 ft 3
Find the sum of the volumes
288 + 72 = 360 ft 3
The volume of the composite figure = 360 ft 3
4 Find the base area B of the rectangular prism
B = bh
= ( 40 ) ( 50 ) = 2000 ft 2
Find the volume of the rectangular prism
V = Bh
= ( 2000 ) ( 15 ) = 30000 ft 3
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 40 ) ( 10 ) = 200 ft 2
Find the volume of the triangular prism
V = Bh
= ( 200 ) ( 50 ) = 10000 ft 3
Find the sum of the volumes
30000 + 10000 = 40000 ft 3
The volume of the barn is 40000 ft 3
5 Find the base area B of the trapezoidal prism
B = 1 __ 2 ( b 1 + b 2 ) h
= 1 __ 2 ( 10 + 12 ) 5
= 1 __ 2 ( 22 ) 5 = 55 cm
2
Find the volume of the trapezoidal prism
V = Bh
= ( 55 ) ( 7 ) = 385 cm 3
The volume of the container is 385 cm 3
6 Find the volume of each prism using the formula
V = Bh Then add the volumes of all the prisms
Independent Practice
7 The area of the base of the prism is given 35 in 2
Find the volume of the prism
V = Bh
= ( 35 ) ( 5 ) = 175 in 3
The volume of the trap is 175 in 3
8 The shape of the ramp is triangular prism
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 7 ) ( 6 ) = 21 in
2
Find the volume of the triangular prism
V = Bh
= ( 75 ) ( 7 ) = 525 in 3
The volume of the ramp is 525 in 3
9 Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 8 ) ( 4 ) = 16 ft 2
Find the volume of the triangular prism
V = Bh
= ( 16 ) ( 24 ) = 384 ft 3
The space contained within the goal is 384 ft 3
10 Find the base area B of the trapezoidal prism
B = 1 __ 2 ( b 1 + b 2 ) h
= 1 __ 2 ( 7 + 5 ) 4
= 1 __ 2 ( 12 ) 4 = 24 in
2
Find the volume of the trapezoidal prism
V = Bh
= ( 24 ) ( 8 ) = 192 in 3
The volume of the gift box is 192 in 3
11 Find the volume of the triangular prism
V = Bh
= ( 20 ) ( 15 ) = 300 in 3
The units for volume are incorrect the volume is
300 cubic inches
12 The area of the base of the hexagonal prism is
given B = 234 in 3
Find the volume of the hexagonal prism
V = Bh
= ( 234 ) ( 3 ) = 702 in 3
Copyright copy by Houghton Mifflin Harcourt 66 All rights reserved
Find the base area B of the rectangular prism
B = bh
= ( 3 ) ( 3 ) = 9 in 2
Find the volume of the rectangular prism
V = Bh
= ( 9 ) ( 3 ) = 27 in 3
Find the sum of the volumes
702 + 27 = 972 in 3
The volume of the figure is 972 in 3
13 Find the base area B of the larger rectangular prism
B = bh
= ( 75 ) 375 = 28125 m 2
Find the volume of the larger rectangular prism
V = Bh
= ( 28125 ) ( 75 ) asymp 21094 cm 3
Find the base area B of the smaller rectangular
prism
Find the measure of the base
15 - 75 = 75
Find the base area B of the larger rectangular prism
B = bh
= ( 75 ) 375 = 28125 m 2
Find the volume of the smaller rectangular prism
V = Bh
= ( 28125 ) ( 375 ) asymp 10547 cm 3
Find the sum of the volumes of the prisms
21094 + 10547 = 31641 m 3
The volume of the figure rounded to the nearest
hundredth is 31641 m 3
14 Find the volume of the hexagonal candle
V = Bh
= ( 21 ) ( 8 ) = 168 cm 3
Find the amount of wax Josie would have after
making the hexagonal candle
260 - 168 = 92 cm 3
Find the volume of the triangular candle
V = Bh
= ( 7 ) ( 14 ) = 98 cm 3
Find the amount of wax Josie would have after
making the hexagonal candle
260 - 168 = 92 cm 3
Find the area of the base of a triangular candle with
a height of 14 cm
V = Bh
92 = B ( 14 )
92 ___ 14
= B ( 14 ) _____ 14
6 8 ___ 14
= B asymp 657
No the area of the base of the triangular candle
must be less than or equal to about 657 cm 2
15 The base of trapezoidal prism is given 36 in 2 Find
the volume of the trapezoidal prism
V = Bh
= ( 36 ) ( 5 ) = 180 in 3
The base of triangular prism is given 32 in 2
Find the volume of the trapezoidal
prism V = Bh
= ( 32 ) ( 6 ) = 192 in 3
Triangular prism you get 192 in 3 for the same price
you would pay for 180 in 3 with the trapezoidal prism
Focus on Higher Order Thinking
16 Find the area of the base of the trapezoidal prism
V = Bh
286 = B ( 8 )
286 ____ 8 = B ( 8 )
3575 = B
Find the missing dimension of the base of the
trapezoidal prism
1 __ 2 ( 2 + b 2 ) 13 = 3575
1 __ 2 ( 2 + b 2 ) ( 13 ___
13 ) = 3575 _____
13
( 2 ) 1 __ 2 ( 2 + b 2 ) = ( 2 ) 275
2 + b 2 = 55
_ -2 _ -2
b 2 = 35 ft
The missing dimension is 35 ft
17 Find the area of the base of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 10 ) 6 = 30 cm
2
Find the volume of the triangular prism
V = Bh
= ( 30 ) ( 25 ) = 75 cm 3
Find the mass of the doorstop
mass asymp ( V in cm 3 ) ( 86 g
_____ cm
3 )
asymp ( 75 cm 3 ) ( 86 g
_____ cm
3 ) = 645 g
The volume of the doorstop is 75 cm 3 The mass is
about 645 g
18 If both the base and height of the triangular base are
tripled the area of the base is multiplied by 9
Tripling the height of the prism as well means the
volume of the prism is multiplied by 27
19 Use the formula for the volume of a trapezoidal
prism to find a set of dimensions that have a volume
of 120 cm 3
V = Bh
V = [ 1 __ 2 ( b 1 + b 2 ) h 1 ] h 2
120 ≟ [ 1 __ 2 ( 2 + 6 ) 4 ] 75
= [ 1 __ 2 ( 8 ) 4 ] 75
= [ 16 ] ( 75 ) = 120
Try another set of dimensions in the formula
V = Bh
V = [ 1 __ 2 ( b 1 + b 2 ) h 1 ] h 2
120 ≟ [ 1 __ 2 ( 1 + 7 ) 25 ] 12
= [ 1 __ 2 ( 8 ) 25 ] 12
= [ 10 ] 12 = 120
Copyright copy by Houghton Mifflin Harcourt 67 All rights reserved
Sample answers ( 1 ) height of trapezoid = 4 cm
base lengths = 2 cm and 6 cm height of prism
= 75 cm ( 2 ) height of trapezoid = 25 cm base
lengths = 1 cm and 7 cm height of prism = 12 cm
MODULE 9
Ready to Go On
1 r = 7 m A = π r 2 C = 2πr A asymp 314 sdot ( 7 ) 2
C asymp 2 sdot 314 sdot 7 A asymp 314 sdot 49
C asymp 4396 m A asymp 15386 m 2
2 d = 12 cm d = 6 cm so r = 12 ___ 2 = 6 ft
C = πd A = π r 2 C asymp 314 ( 12 ) A asymp 314 sdot ( 6 ) 2
C asymp 3768 cm A asymp 314 sdot 36
A asymp 11304 ft 2
3 The figure is a composite of a semicircle with
diameter = 16 m so radius is 16 ___ 2 = 8m and a
triangle with base = 16 m and height = 10 m
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 8 ) 2
A asymp 1 __ 2 sdot 314 sdot 64
A asymp 10048 m 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 16 sdot 10
A = 1 __ 2 sdot 160
A = 80 m 2
The total area is the sum
80 + 10048 = 18048 m 2
4 The figure is a composite of a parallelogram with
base = 20 cm and height = 45 cm and a rectangle
with length = 20 cm and height = 55 cm
Area of parallelogram A = bh
A = 20 sdot 45
A = 90 c m 2
Area of rectangle
A = ℓw = 20 sdot 55 = 110 c m 2
The total area is the sum
90 + 110 = 200 cm 2
5 Find the area of the triangular base
Area of triangle = 1 __ 2 bh
1 __ 2 ( 4 ) 3 = 6 cm 2
Find the perimeter of the base
P = 3 + 4 + 5 = 12 cm
Find the surface area
S = Ph + 2B
S = 12 ( 10 ) + 2 ( 6 )
thinsp=120 + 12
thinsp= 132 cm 2
Find the volume of the prism
V = Bh
= ( 6 ) 10
= 60 cm 3
6 Find the area of the composite base formed by a
rectangle and a triangle
Area of triangle = 1 __ 2 bh
1 __ 2 ( 4 ) 15 = 3 yd 2
Area of rectangle = bh
( 4 ) 2 = 8 yd 2
Area of the composite base 3 + 8 = 11 yd 2
Find the perimeter of the composite base
P = 4 + 2 + 25 + 25 + 2 = 13 yd
Find the surface area
S = Ph + 2B
S = 13 ( 25 ) + 2 ( 11 )
thinsp= 325 + 22
thinsp= 545 yd 2
The area of the base of the pentagonal prism
is given
B = 234 yd 3
Find the volume of the prism
V = Bh
= ( 11 ) 25
= 275 yd 3
7 Sample answer You can use a composite figure to
model a room then find surface area to decide how
much paint you need to paint the room
Copyright copy by Houghton Mifflin Harcourt 68 All rights reserved
Solutions KeyStatistics
unit
5MODULE 10 Random Samples and Populations
Are You Ready
1 x ___16
=45___40
40x=720
40x ____40
=720____40
x=18
2 x __5=1__
4
4x=5
4x ___4
=5__4
x=5__4=125
3 25___10
=x ___10
125=10x
125____10
=10x ____10
125=x
4 x __6
=2__9
9x= 12
9x ___9
=12___9
x=12___9=4__
3
5 4748495152575960range=60-47=13
6 4566689121213range=13-4=9
7 95979799100106108115range=115-95=20
8 121319273539476671range=71-12=59
9 mean=3+5+7+3+6+4+8+6+9+5_________________________________10
=56
10 mean=81+94+113+67+62+75____________________________6
=82
LESSON 101
Your Turn
4 Yeseveryemployeehadanequalchanceofbeingselected
5 Thequestionisbiasedsincecatsaresuggested
6 ThequestionisnotbiasedItdoesnotleadpeopletopickaparticularseason
Guided Practice
1 Method1ASampleanswer
Random Sample of Seventh Grade Male Students
Student Shoe SizeArturo 75
Jimmy 80
Darnell 90
Ping 75
Zach 85
Jamar 80
BSampleanswer
75+80+90+75+85+80___________________________6
=485____6
asymp81
Meanasymp81
Method2ASampleanswer
Student Shoe Size Student Shoe SizeReggie 85 Ling 85
Stan 80 Marcus 90
Alejandro 90 Tio 85
BSampleanswer
85+80+90+85+90+85____________________________6
=515____6 =86
Mean=size86
2Method1producesresultsthataremorerepresentativeoftheentirestudentpopulationbecauseitisarandomsample
3 Method2producesresultsthatarelessrepresentativeoftheentirestudentpopulationbecauseitisabiasedsample
4 YesSampleanswerWhatisyourfavoritecolor
5 Selectarandomsampleofsufficientsizethatrepresentsthepopulationandaskeachparticipantunbiasedquestions
Independent Practice
6 SampleanswerPaulrsquossamplewasbiasedMaybehisfriendsstudiedmorethanothers
7 SampleanswerNancyrsquossampledidnotincludeasmanystationsThereportcouldincludestationsnationwide
8 ItisabiasedsampleStudentswhoarenrsquotontheteamwonrsquotbeselected
CopyrightcopybyHoughtonMifflinHarcourt 69 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U5M10indd 69 103113 216 AM
9 Itisbiasedbecausestudentswhoarenrsquotinthatclasswonrsquotbeselected
10 Itisarandomsamplebecauseallseventhgradershaveanequalchanceofbeingselected
11 Itisarandomsamplebecausetheorganizationselectsnamesatrandomfromallregisteredvoters
12 Itisbiasedbecausebasketballismentioned
13 Jaersquosquestionisnotbiasedsinceitdoesnotsuggestatypeofarttostudents
Focus on Higher Order Thinking
14 CollinrsquosmethodbetterrepresentstheentirestudentpopulationbecauseheusedarandomsampleKarlrsquosmethodpickedpeoplethatcouldallbefriendsthatgotofootballgamestogetherThesamplemaynotbestrepresenttheentirestudentpopulation
15 a Every10thstudentoutof600meansthatBarbarasurveyed60studentsThiswasarandomsample
b 35___60
= x ____100
xasymp58
Thepercentis58____100
=58
ItappearsreasonablebecauseBarbarausedarandomsampleandsurveyedasignificantpercentofthestudents
16 CarloiscorrectTherearemanyvalidwaystoselectarepresentativesamplefromapopulation
LESSON 102
Your Turn
5 damagedMP3sinsample
______________________sizeofsample
=damagedMP3sinpopulation
________________________sizeofpopulation
6___50
= x_____3500
6sdot70______50sdot70
= x _____3500
420_____3500
= x_____3500
x=420420damagedMP3s
Guided Practice
1
6 7 8 9 10 11 12 13 14 1550 1 2 3 4
2 Orderthedatafindtheleastandgreatestvaluesthemedianandthelowerandupperquartiles
6 7 7 107 114 4 54
Leastvalue
4
Lower quartile
4
Median
65
Upper quartile
7
Greatestvalue11
Drawaboxplot
10 1550
3 Themostcommonagesofchildrenthatusethelibraryare4and7
4 Therangeofagesofchildrenthatusethelibraryisfrom4to11
5 Themedianageofchildrenthatusethelibraryis65
6 defectivephonesinsample
______________________sizeofsample
=defectivephonesinpopulation
_________________________sizeofpopulation
4___60
= x_____4200
4sdot70______60sdot70
= x_____4200
280_____4200
= x_____4200
x=280About280smartphonesintheorderarelikelytobedefective
7 infectedelkinsample
__________________sizeofsample
=infectedelkinpopulation
____________________sizeofpopulation
8___50
= x_____4500
8sdot90______50sdot90
= x_____4500
720_____4500
= x_____4500
x=720About720elkarelikelytobeinfected
8 YoucansetupproportionsusinginformationobtainedinarandomsampleofthepopulationForinstancethenumberofdefectivepartsinabatchcanbeusedtopredicthowmanypartswillbedefectiveinadifferent-sizebatch
divide060
divide060
CopyrightcopybyHoughtonMifflinHarcourt 70 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U5M10indd 70 103113 218 AM
Independent Practice
9 number of people with mispriced item in sample
_______________________________________ size of sample
=
number of people with mispriced item in one day
_______________________________________ size of population
4 ___ 50
= x ____ 600
4 sdot 12 ______ 50 sdot 12
= x ____ 600
48 ____ 600
= x ____ 600
x = 48
About 48 people are likely to have a mispriced item
10 number of boxes with at least one broken crayon in sample
_______________________________________________ size of sample
=
total number of boxes with at least one broken crayon
___________________________________________ size of population
2 ___ 20
= x ____ 130
2 sdot 65 _______ 20 sdot 65
= x ____ 130
13 ____ 130
= x ____ 130
x = 13
About 13 boxes will have at least one broken crayon
11 number of puppies
________________ size of sample
= total number of puppies
___________________ size of population
12 ___ 60
= x _____ 1200
12 sdot 20 ______ 60 sdot 20
= x _____ 1200
240 _____ 1200
= x _____ 1200
x = 240
About 240 puppies are in all of the cityrsquos animal
shelters
12 number of hawks building nests
__________________________ size of sample
= total number of hawks
__________________ size of population
12 ___ 72
= x ______ 10800
12 sdot 150 _______ 72 sdot 150
= x ______ 10800
1800
______ 10800
= x ______ 10800
x = 1800
About 1800 hawks are building nests
13 Yes this seems reasonable because 23 + 27
_______ 2 = 25
is the median of the data
14 Order the data
11 12 12 12 13 13 13 14 14 14 15 17 18 18
19 22
The total number of marathoners is 16 and of those
12 run 13 miles or more
12 ___ 16
= x ____ 100
12 sdot 625 ________ 16 sdot 625
= x ____ 100
75 ____ 100
= x ____ 100
x = 75
No The statement should say that 75 of female
marathoners run 13 or more miles a week
15
6 7 8 9 1050 1 2 3 4
Sample answer Most students at Garland have 2 or
fewer siblings
16 The box plot should show that at least 50 of the
ages are between 20 and 40 years of age
17 Kudrey needs to find the median and the lower and
upper quartiles and plot those points He assumed
all quartiles would be equally long when each
quartile represents an equal number of data values
Focus on Higher Order Thinking
18 Yes the least and greatest data values The median
and quartiles may or may not be actual data values
depending on how many values are in the data
19 A box plot Since every number is different a dot
plot would only have one dot over each value which
doesnrsquot give much information The box plot would
show the median the range and where data values
are concentrated if in fact they are
20 The typical salary at this company is $24000 the
median Yes it is misleading the average is thrown
off by the outlier value of $79000
Copyright copy by Houghton Mifflin Harcourt 71 All rights reserved
9 a 56 + 43 + 62 + 63 + 33 + 34 + 38 + 51 + 59 + 59
___________________________________________ 10
= 498
The average is 498 palms
b 498 sdot 64 = 31872
There are about 3187 palms on the entire farm
Focus on Higher Order Thinking
10 55 + 57 + 57 + 58 + 59 + 59 + 59 + 59 + 59 + 61 + 62 + 62 + 63 + 64 + 66
_________________________________________________________________ 15
= 60
The mean height is 60 inches Yes it is a good sample generated randomly and contains about 20 of the entire
population so it should provide a good estimate of the mean height of all competitors But taking more samples to
gauge the variability among the samples would make for a more valid estimate
11 Sample answer Answers will vary based on each studentrsquos results but should be about 13 or 14
12 Sample answer The larger the size of the random sample the more likely it is to represent the population
accurately
LESSON 103
Guided Practice
1 (1 600) 20
2 50 51 600
3 No In the sample 4 numbers (38 26 31 and 31)
represent defective batteries which is 20 of the
total In the shipment 50 out of 600 or about 8 of
the batteries are defective
4 Sample answer A too-small or non-random sample
is likely to pick unrepresentative data values
Independent Practice
5 Shop A 10 ___ 50
times 500 = 100
Shop B 23 ____ 100
times 500 = 115
Shop C 7 ___ 25
times 500 = 140
Shop A sells 100 whole-wheat bagels
Shop B sells 115 whole-wheat bagels
Shop C sells 140 whole-wheat bagels
6 From most to least likely B A C Shop Brsquos sample
would be the most representative because it
contained the most bagels Shop Crsquos sample would
be the least representative because it contained the
fewest bagels
7 She could use either the Shop A or Shop B sample
Both use a sufficient number of bagels to be
reasonably accurate The sample from Shop C uses
too few bagels to be accurate
8 2 of the 20 T-shirts in the sample are below quality
standards Because 2 ___ 20
times 1000 = 100 the predic-
tion would be that about 100 of the 1000 T-shirts are
below quality standards This is 1 1 __ 3 times the actual
count of 75
Copyright copy by Houghton Mifflin Harcourt 72 All rights reserved
MODULE 10
Ready to Go On
1 The population is the customers in the companyrsquos
computer database The sample is biased because
the customers surveyed are more likely to value their
service
2 number of students who speak 3 or more languages
__________________________________________ size of sample
= total number of students ____________________ size of population
18 ____ 270
= x ______ 30330
18 sdot 337 ____
3 ________
270 sdot 337 ____ 3
= x ______ 30330
2022
______ 30330
= x ______ 30330
x = 2022
About 2022 students speak three or more
languages
3 Two of the random numbers 13 and 167 represent
defective MP3 players
simulated defective players
______________________ size of simulation
= defective players
______________ shipment
2 ___ 10
= x _____ 5000
2 middot 500 _______ 10 middot 500
= x _____ 5000
1000
_____ 5000
= x _____ 5000
x = 1000
Based on the sample about 1000 MP3 players are
defective
4 No the sample is too small compared to the size of
the shipment
5 Sample answer You can make predictions about
populations that are too large to survey
Copyright copy by Houghton Mifflin Harcourt 73 All rights reserved
MODULE 11 Analyzing and Comparing Data
Are You Ready
0875
1 8 ⟌ _
7000
_ -6 400
600
_ -560
40
_ -40
0
0875 875
08
2 5 ⟌ _
40
_ -4 0
0
08 80
025
3 4 ⟌ _
100
_ -80
20
_ -20
0
025 25
03
4 10 ⟌ _
30
_ -3 0
0
03 30
5 4 6 7 7 9 11 15 17
7 + 9
_____ 2 = 8
Median = 8
Mode = 7
6 36 37 40 43 44 49 50 51 56
Median = 44
Mode none
7 9 + 16 + 13 + 14 + 10 + 16 + 17 + 9
________________________________ 8
= 13
Mean = 13
8 108 + 95 + 104 + 96 + 97 + 106 + 94
________________________________ 7 = 100
Mean = 100
LESSON 111
Your Turn
2 Shape dot plots for field hockey players and
softball players have a similar spread
Center center of the field hockey dot plot is less
than the center for softball or basketball players
Spread dot plots for field hockey players and softball
players have a similar spread
3 The median is the middle value Listing the values
in order
1 4 4 4 5 5 5 6 6 6 6 7 7 8 11
In this case median 6 h
range 10 h
The median for internet usage is greater than the
median for exercise and the range is less than the
range for exercise
Guided Practice
1 Class A clustered around two areas
Class B clustered in the middle The dot plots
appear to have about half of the data clustered in
one area
2 Class A two peaks at 4 and 13 mi
Class B looks centered around 7 mi
3 Class A spread from 4 to 14 mi a wide gap with
no data
Class B spread from 3 to 9 mi
4 Class A
4 4 4 4 4 5 5 5 6 6 12 13 13 13 13 14 14
median 6
Class B
3 4 4 4 5 5 5 5 6 6 7 7 7 7 7 8 8 9
median 6
The median for both dot plots is 6 miles
5 Range for class A 14 - 4 = 10 mi
Range for class B 9 - 3 = 6 mi
6 The medians allow you to compare the centers
The ranges allow you to compare the spreads
Independent Practice
7 The dots have a relatively even spread with a peak
at 8 letters
8 The center of the graph is between 6 and 7 letters
9 The dots spread from 3 to 9 letters
10 The mean is the average
3 + 4 + 4 + 5 + 5 + 6 + 7 + 7 + 8 + 8 + 8 + 9
________________________________________ 12
74 ___ 12
asymp 617
Mean asymp 617
3 3 4 5 5 6 7 7 8 8 8 9
Because there are two middle values take their
average
6 + 7
_____ 2 = 13 ___
2 = 65
Median 65
Range 9 - 3 = 6
11 AL clustered in one small interval with an outlier to
the left
VA relatively uniform in height over the same
interval
Copyright copy by Houghton Mifflin Harcourt 74 All rights reserved
12 ALcenteredbetween8and9daysofrainVAcenteredaround10daysofrain
13 ALspreadsfrom1to12daysofrainanoutlierat1VAspreadsfrom8to12daysofrain
14 LynchburgVAhasmoreconsistentlevelsofrainandmorerainpermonthcomparedtoMontgomeryAL
15 GroupAclusteredtotheleftofsize9GroupBclusteredtotherightofsize9
16 OrderedvaluesforgroupA6577757575888888585913Thereare15itemsofdataSince15isoddthereisamiddlenumber8Sothereisnoneedtoaverageanyvalues
MedianforGroupAsize8OrderedvaluesforgroupB859999959595951010105105105115MedianforGroupBsize95
17 GroupArangewithoutlier=13-65=65withoutoutlier=9-65=25GroupBrange=115-85=3
18 SampleanswerGroupAcouldbechildrenandGroupBcouldbeadults
Focus on Higher Order Thinking
19 YesSampleansweronegroupoffivestudentscouldhavethefollowingnumberofpets12345Anothergroupoffivestudentscouldhavethefollowingnumberofpets13335Forbothgroupsofstudentsthemedianwouldbe3andtherangewouldbe4
20RangeanoutliergreatlyincreasestherangewhereasthemedianwillgenerallynotbegreatlyaffectedasitisinthemiddleofallthevaluesAdotplotwillshowboth
LESSON 112
Your Turn
3 SampleanswerTheboxeshavesimilarshapesalthoughGroupBhasashorterboxandshorterwhiskersGroupBrsquosmedianisgreaterthanGroupArsquosGroupBrsquosshorterboxmeansthemiddle50ofitsdataareclosertogetherthanthemiddle50ofGroupArsquos
4 SampleanswerTheshapeissimilartoStoreArsquosThemedianisgreaterthanStoreArsquosandlessthanStoreBrsquosTheinterquartilerangeisaboutthesameasStoreArsquosandlongerthanBrsquos
Guided Practice
1 Minimum72 Maximum88
2 Median79
3 Range88-72=16 IQR85-75=10
4 Themedianheightforhockeyplayersis70inthemedianheightforvolleyballplayersis74Thereforevolleyballplayershavethegreatermedianheight
5 Theminimumheightforhockeyplayersis64intheminimumheightforvolleyballplayersis67inSohockeyplayershavetheshortestplayer
6 IQRforhockeyplayers76-66=10IQRforvolleyballplayers78-68=10BothgroupshaveanIQRof10
7 SampleanswerMinimumandmaximumvaluesmedianrangeandIQRs
Independent Practice
8 CarAhasaminimumof165inandamaximumof210inCarBhasaminimumof160inandamaximumof205inCarAhasamedianof180inCarBhasamedianof185in
9 RangeofCarA210-165=45RangeofCarB205-160=45IQRofCarA195-170=25IQRofCarB200-175=25Bothcarshaverangesof45inandinterquartilerangesof25in
10 CarBhasagreatermediandistancethanCarATheinterquartilerangesarethesamesothemiddle50ofthejumpdistancesforthetwocarshavethesamevariability
11 CarAhaslessvariabilityinthelowestquarterofitsdataandgreatervariabilityinthehighestquarterofitsdataThevariabilityisreversedforCarB
12 CityBhasthelowestpriceof$400andalsohasthehighestpriceof$625
13 MedianforCityA$475MedianforCityB$450Difference475-450=$25CityAhasthehighermedianpriceanditis$25higher
14 SampleanswerCityBabout50ofcarsinCityBleaseforlessthan$450ascomparedtoonly25ofcarsinCityA
15 SampleanswerCityAhasagreatermediancarleasingcostthanCityBCityAhasagreaterIQRofcarleasingcoststhanCityBCityBhasamorepredictablecarleasingcostthanCityAforthemiddle50ofdatavalues
CopyrightcopybyHoughtonMifflinHarcourt 75 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U5M11indd 75 103113 221 AM
Focus on Higher Order Thinking
16 The box plot with the longer box has more variability
in the middle 50 of the values
17 You can identify the minimum and maximum values
and the range of the data You can identify the
quartiles including the lower and upper quartiles
and the median as well as the interquartile range
Together these values help you recognize the
center of the data both the median and the middle
50 It helps you to recognize how spread out the
data are overall and how spread out the middle
50 of the values are around the median A dot
plot contains all the data values which a box plot
does not
18 Sample answer The range tells you very little but
the interquartile range tells you how closely the
middle half of the data cluster around the median
LESSON 113
Your Turn
1 Team 1
Mean
44 + 47 + 67 + 89 + 55 + 76 +85 + 80 + 87 + 69 + 47 + 58 = 804
804 divide 12 = 67
Mean absolute deviation
ǀ 44 - 67 ǀ = 23 ǀ 47 - 67 ǀ = 20
ǀ 67 - 67 ǀ = 0 ǀ 89 - 67 ǀ = 22
ǀ 55 - 67 ǀ = 12 ǀ 76 - 67 ǀ = 9
ǀ 85 - 67 ǀ = 18 ǀ 80 - 67 ǀ = 13
ǀ 87 - 67 ǀ = 20 ǀ 69 - 67 ǀ = 2
ǀ 47 - 67 ǀ = 20 ǀ 58 - 67 ǀ = 11
Mean of absolute values
23 + 20 + 0 + 22 + 12 + 9 +18 + 13 + 20 + 2 + 20 + 11 = 170
170 divide 12 asymp 142
Team 2
Mean
40 + 32 + 52 + 75 + 65 + 70 +72 + 61 + 54 + 43 + 29 + 32 = 625
625 divide 12 asymp 521
Mean absolute deviation
ǀ 40 - 521 ǀ = 121 ǀ 32 - 521 ǀ = 201
ǀ 52 - 521 ǀ = 01 ǀ 75 - 521 ǀ = 229
ǀ 65 - 521 ǀ = 129 ǀ 70 - 521 ǀ = 179
ǀ 72 - 521 ǀ = 199 ǀ 61 - 521 ǀ = 89
ǀ 54 - 521 ǀ = 19 ǀ 43 - 521 ǀ = 91
ǀ 29 - 521 ǀ = 231 ǀ 32 - 521 ǀ = 201
Mean of absolute values
121 + 201 + 01 + 229 +129 + 179 + 199 + 89 +19 + 91 + 231 + 201 = 169
169 divide 12 asymp 141
Difference in means
67 - 521 = 149
149 divide 141 asymp 11
The difference of the means is about 11 times the
MAD
2 There is much more overlap between the two
distributions
Guided Practice
1 Class 1 mean
12 + 1 + 6 + 10 + 1 + 2 + 3 +10 + 3 + 8 + 3 + 9 + 8 + 6 + 8 = 90
90 divide 15 = 6
Class 2 mean
11 + 14 + 11 + 13 + 6 + 7 + 8 + 6 +8 + 13 + 8 + 15 + 13 + 17 + 15 = 165
165 divide 15 = 11
Class 1 mean absolute deviation
ǀ 12 - 6 ǀ = 6 ǀ 1 - 6 ǀ = 5 ǀ 6 - 6 ǀ = 0
ǀ 10 - 6 ǀ = 4 ǀ 1 - 6 ǀ = 5 ǀ 2 minus 6 ǀ = 4
ǀ 3 - 6 ǀ = 3 ǀ 10 - 6 ǀ = 4 ǀ 3 - 6 ǀ = 3
ǀ 8 - 6 ǀ = 2 ǀ 3 - 6 ǀ = 3 ǀ 9 - 6 ǀ = 3
ǀ 8 - 6 ǀ = 2 ǀ 6 - 6 ǀ = 0 ǀ 8 - 6 ǀ = 2
6 + 5 + 0 + 4 + 5 + 4 + 3 + 4 +3 + 2 + 3 + 3 + 2 + 0 + 2 = 46
46 divide 15 asymp 3
Class 2 mean absolute deviation
ǀ 11 - 11 ǀ = 0 ǀ 14 - 11 ǀ = 3 ǀ 11 - 11 ǀ = 0
ǀ 13 - 11 ǀ = 2 ǀ 6 - 11 ǀ = 5 ǀ 7 - 11 ǀ = 4
ǀ 8 - 11 ǀ = 3 ǀ 6 - 11 ǀ = 5 ǀ 8 - 11 ǀ = 3
ǀ 13 - 11 ǀ = 2 ǀ 8 - 11 ǀ = 3 ǀ 15 - 11 ǀ = 4
ǀ 13 - 11 ǀ = 2 ǀ 17 - 11 ǀ = 6 ǀ 15 - 11 ǀ = 2
0 + 3 + 0 + 2 + 5 + 4 + 3 + 5 +3 + 2 + 3 + 4 + 2 + 6 + 2 = 44
44 divide 15 asymp 3
2 Difference in means
11 minus 6 = 5
5 divide 3 asymp 167
3 Sample answer The variation and overlap in the
distributions make it hard to make any convincing
comparison
4 To see how statistical measures vary among the
different samples
Independent Practice
5 23 + 38 + 39 + 48 + 55 + 56 + 71 +86 + 57 + 53 + 43 + 31 = 600
600 divide 12 = 50
ǀ 23 - 50 ǀ = 27 ǀ 38 - 50 ǀ = 12
ǀ 39 - 50 ǀ = 11 ǀ 48 - 50 ǀ = 2
ǀ 55 - 50 ǀ = 5 ǀ 56 - 50 ǀ = 6
ǀ 71 - 50 ǀ = 21 ǀ 86 - 50 ǀ = 36
ǀ 57 - 50 ǀ = 7 ǀ 53 - 50 ǀ = 3
ǀ 43 - 50 ǀ = 7 ǀ 31 - 50 ǀ = 19
27 + 12 + 11 + 2 + 5 + 6 + 21 +36 + 7 + 3 + 7 + 19 = 156
156 divide 12 = 13
The mean is 50degF and the MAD is 13degF
Copyright copy by Houghton Mifflin Harcourt 76 All rights reserved
6 ǀ 23 - 8 ǀ = 15 ǀ 38 - 23 ǀ = 15
ǀ 39 - 24 ǀ = 15 ǀ 48 - 33 ǀ = 15
ǀ 55 - 40 ǀ = 15 ǀ 56 - 41 ǀ = 15
ǀ 71 - 56 ǀ = 15 ǀ 86 - 71 ǀ = 15
ǀ 57 - 42 ǀ = 15 ǀ 53 - 38 ǀ = 15
ǀ 43 - 28 ǀ = 15 ǀ 31 - 16 ǀ = 15
The difference between each average monthly
temperature for City 1 and the corresponding
temperature for City 2 is 15degF
7 50 - 15 = 35
The mean is 35degF and the MAD is 13degF The
mean for City 2 must be 15degF less than the mean
for City 1 and the MAD must be the same
8 50 - 35 = 15
15 divide 13 asymp 12
The difference in the means as a multiple of the
mean absolute deviations is about 12
9
0 4 8 12 16 20 24 28 32 36 40 44
Medians
School B
School A
0 4 8 12 16 20 24 28 32 36 40 44
Means
School B
School A
Both distributions show longer travel times for school
A The distributions of the medians show less
overlap so it is more convincing
10 State A 48 - 38 = 10
10 divide 6 asymp 17
State B 50 - 42 = 8
8 divide 4 = 2
Sample answer The difference in ages is more
significant for State A if you look at the difference in
mean ages but the difference in mean ages is more
significant in State B if you consider variability as
well
11 Smiths Range 70 - 64 = 6
Median 665
Thompsons Range 80 - 74 = 6
Median 77
77 - 665 = 105
105 divide 6 = 175
The difference in the medians is 175 times the
ranges
Focus on Higher Order Thinking
12 Sample answer Jill can reasonably expect the
median of the medians of the samples to be 35
The median of the medians should be close to the
median of the population which should be 35
The outcomes are equally likely
13 Sample answer Ramonrsquos results should produce
more reliable inferences The larger the sample
size the less variability there should be in the
distributions of the medians and means
14 Sample answer Sethrsquos statement is incorrect for any
situation in which the MADs of the population are
not very similar
MODULE 11
Ready to Go On
1 The mean for the start of the school year is given by
5 + 6 + 6 + 7 + 7 + 7 + 7 + 8 + 8 + 8 + 8 + 9 + 9 + 10
________________________________________________ 14
= 105 ____ 14
= 75 mi
The mean for the end of the school year is given by
6 + 6 + 7 + 7 + 8 + 8 + 8 + 8 + 9 + 9 + 9 + 10 + 10 + 10
__________________________________________________ 14
= 115 ___ 14
asymp 82 mi
In summary Start 75 mi End about 82 mi
2 The median is the middle value
List of ordered values for start of school year
5 6 6 7 7 7 7 8 8 8 8 9 9 10
Because there are two middle values take their
average
7 + 8
_____ 2 = 15 ___
2 = 75
Median 75
List of ordered values for end of school year
6 6 7 7 8 8 8 8 9 9 9 10 10 10
Because there are two middle values we would
generally take their average but since they are both
the same and equal to 8
Median 8
Therefore Start 75 mi End 8 mi
3 Range for start of school year 10 - 5 = 5 mi
Range for end of school year 10 - 6 = 4 mi
Therefore Start 5 mi End 4 mi
4 Median for Airplane A 210 in
Median for Airplane B 204 in
Airplane A has a greater median flight length
5 IQR for Airplane A 225 - 208 = 17 in
IQR for Airplane B 230 - 195 = 35 in
Airplane B has a greater interquartile range
Copyright copy by Houghton Mifflin Harcourt 77 All rights reserved
6 The means for the shade plants
7 + 11 + 11 + 12 + 9 + 12 + 8 + 10
______________________________ 8
= 10
The means for the sun plants
21 + 24 + 19 + 19 + 22 + 23 + 24 + 24
__________________________________ 8 = 22
Range of the shade plants 12 - 7 = 5
Range of the sun plants 24 - 19 = 5
Difference in the means 22 - 10 = 12
12 ___ 5
= 24
The difference in the means is 24 times the ranges
7 Sample answer By graphing real-world data you
can identify similarities and differences in related
groups
Copyright copy by Houghton Mifflin Harcourt 78 All rights reserved
MODULE 12 Experimental Probability
Are You Ready
1 6 ___ 10
= 6 divide 2 ______ 10 divide 2
= 3 __ 5
2 9 ___ 15
= 9 divide 3 ______ 15 divide 3
= 3 __ 5
3 16 ___ 24
= 16 divide 8 ______ 24 divide 8
= 2 __ 3
4 9 ___ 36
= 9 divide 9 ______ 36 divide 9
= 1 __ 4
5 45 ___ 54
= 45 divide 9 ______ 54 divide 9
= 5 __ 6
6 30 ___ 42
= 30 divide 6 ______ 42 divide 6
= 5 __ 7
7 36 ___ 60
= 36 divide 12 _______ 60 divide 12
= 3 __ 5
8 14 ___ 42
= 14 divide 14 _______ 42 divide 14
= 1 __ 3
075
9 4 ⟌ _
300
_ -2 80
20
_ -20
0
075
0875
10 8 ⟌ _
7000
_ -6400
600
_ -560
40
_ -40
0
0875
015
11 20 ⟌ _
300
_ -2 00
100
_ -100
0
015
038
12 50 ⟌ _
1900
_ -15 00
4 00
_ -4 00
0
038
13 67 = 67 ____ 100
= 067
14 31 = 31 ____ 100
= 031
15 7 = 7 ____ 100
= 007
16 146 = 100 + 46
= 100 ____ 100
+ 46 ____ 100
= 1 + 046
= 146
17 013 = 13
18 055 = 55
19 008 = 8
20 116 = 116
LESSON 121
Your Turn
3 Because every other number from 1 through 16 is
even choosing an even number is as likely as not
and the probability is 1 __ 2
4 There are 20 possible outcomes when picking a
marble from the jar There are 10 purple marbles
Therefore the probability of picking a purple marble
is 10 ___ 20
or 1 __ 2
5 There are 6 possible outcomes when rolling a cube
There are 2 numbers greater than 4 that can be
rolled 5 and 6 Therefore the probability of rolling a
number greater than 4 is 2 __ 6 or 1 __
3
Solutions KeyProbability
UNIT
6
Copyright copy by Houghton Mifflin Harcourt 79 All rights reserved
7 P(event) + P(complement) = 1
P(5) + P(not 5) = 1
1 __ 8 + P(not 5) = 1
P(not 5) = 7 __ 8
The probability of picking a marble that is not 5 is 7 __ 8
8 P(event) + P(complement) = 1
P(even) + P(odd) = 1
1 __ 2 + P(odd) = 1
P(odd) = 1 __ 2
The probability of rolling an odd number is 1 __ 2
Guided Practice
1 The cards are numbered 1 2 3 4 5 6 7 8 9 10
You pick a number greater than 0 8
You pick an even number 5
You pick a number that is at least 2 7
You pick a number that is at most 0 1
You pick a number divisible by 3 3
You pick a number divisible by 5 2
You pick a prime number 4
You pick a number less than the
greatest prime number 6
2 There are no green playing cards in a standard
deck so randomly picking a green card is
impossible 0
3 There are as many red cards as black cards in a
standard deck so it is as likely as not 1 __ 2
4 All of the numbers are less than 12 so they are also
less than 15 The probability is certain 1
5 There are only two numbers between 1 and 12 that
are divisible by 5 5 and 10 Therefore the probability
is unlikely close to 0
6 There are 5 possible outcomes when spinning the
spinner There are two even numbers 2 and 4
Therefore the probability of the spinner landing on
an even number is 2 __ 5
7 There are 52 possible outcomes when picking a
card from a standard deck There are 13 cards with
diamonds Therefore the probability of picking a
card with a diamond is 13 ___ 52
= 1 __ 4
8 P(event) + P(complement) = 1
P(5) + P(not 5) = 1
1 __ 6 + P(not 5) = 1
P(not 5) = 5 __ 6
The probability of not rolling 5 is 5 __ 6
9 P(event) + P(complement) = 1
P(blue) + P(not blue) = 1
1 __ 3 + P(not blue) = 1
P(not blue) = 2 __ 3
The probability of not landing on blue is 2 __ 3
10 P(event) + P(complement) = 1
P(4) + P(not 4) = 1
1 __ 5 + P(not 4) = 1
P(not 4) = 4 __ 5
The probability of not landing on 4 is 4 __ 5
11 P(event) + P(complement) = 1
P(queen) + P(not queen) = 1
4 ___ 52
+ P(not queen) = 1
P(not blue) = 48 ___ 52
= 12 ___ 13
The probability of not picking a queen is 12 ___ 13
12 Sample answer pulling a red marble out of a bag
that contains only blue marbles pulling a white
marble out of a bag that contains only white marbles
Independent Practice
13 There are 52 possible outcomes when picking from
a standard deck of cards There are 8 cards that
have an ace or a king Therefore the probability of
selecting
an ace or a king is 8 ___ 52
or 2 ___ 13
14 P(event) + P(complement) = 1
P(apple or peach) + P(not apple or peach) = 1
9 ___ 12
+ P(not apple or peach) = 1
P(not apple or peach) = 3 ___ 12
or 1 __ 4
Therefore the probability of picking a piece of fruit
that is not an apple or a peach is 3 ___ 12
or 1 __ 4
15 No it is unlikely that she will have oatmeal for
breakfast Since there are 4 choices the probability
that she will choose oatmeal is 1 __ 4 or 25
16 Purple There are a lot more plants with purple
flowers than with white flowers The probability of
selecting a white-flowered plant is 2 __ 9 while the
probability of selecting a purple-flowered plant is 7 __ 9
17 Because she has more colored T-shirts than white
T-shirts it is likely that she will pick a colored T-shirt
She has 14 total T-shirts and 10 of the shirts are
colored Therefore the probability she will choose a
colored T-shirt is 10 ___ 14
or 5 __ 7
18 1 None of the students in the class have red hair so
it is certain that a randomly chosen student will not
have red hair
Copyright copy by Houghton Mifflin Harcourt 80 All rights reserved
19 a There are 14 total coins and 8 blue coins so the
probability that the coin is blue is 8 ___ 14
or 4 __ 7
b Removing 1 of the 8 blue coins leaves 7 blue
coins Adding 3 more to the 6 red coins makes
9 red coins The total of coins in the bag is now
16 Therefore the probability of choosing a red
coin is 9 ___ 16
c Removing 1 of the 6 red coins leaves 5 red coins
Adding 3 to the 8 blue coins makes 11 blue coins
The total of coins in the bag is now 16 Therefore
the probability of choosing a red coin is 5 ___ 16
Focus on Higher Order Thinking
20 Sample answer If some marbles in a jar are heavier
than others then the heavier marbles would sink
and be less likely to be selected
21 Yes Because there are only two colors selecting
not black is equal to selecting red So
P(not black) + P(black) =P(not black) + P(not red) = 1
22 2 is the number of ways the event can happen 7 is
the number of outcomes in the sample space
landing on blue
LESSON 122
Your Turn
7 The total number of spins is 6 + 14 + 10 = 30
Red 10 ___ 30
= 1 __ 3
Yellow 14 ___ 30
= 7 ___ 15
Blue 6 ___ 30
= 1 __ 5
8 Sample answer Let 1 and 2 represent blue 3 and 4
represent white and 5 and 6 represent blue Toss
the cube 50 times to determine the experimental
probability for each color Predict the next ball will be
the color with the greatest experimental probability
Guided Practice
1 The total number of spins is 14 + 7 + 11 + 8 = 40
A 14 ___ 40
= 7 ___ 20
= 035 = 35
B 7 ___ 40
= 0175 = 175
C 11 ___ 40
= 0275 = 275
D 8 ___ 40
= 1 __ 5 = 020 = 20
2 Sample answer Write ldquoyesrdquo on 6 cards and ldquonordquo on
4 cards Draw a card at random 50 times Use the
number of ldquoyesrdquo cards drawn as the prediction
3 Use an experiment to find the number of times the
event occurs for a certain number of trials
Independent Practice
4 6 ___ 10
or 3 __ 5 It is reasonable to assume that Dreersquos
past performance is an indicator of her future
performance There is no way to accurately
represent 3 __ 5 on a number cube with 6 faces
5 Sample answer Compare the number of wins to the
total number of trials
number of wins _________________ total number of trials
= 8 ___ 48
= 1 __ 6
6 There are 20 possible outcomes when picking a
name Ryan is 1 person Therefore the probability
he is chosen is 1 ___ 20
and the probability he is not
chosen is 19 ___ 20
P(Ryan) + P(not Ryan) = 1
1 ___ 20
+ P(not Ryan) = 1
P(not Ryan) = 19 ___ 20
7 Yes because it is based on actual data of weather
patterns
8 Joan Mica hit the ball 8 ___ 48
times or about 17 of her
times at bat Meanwhile Joan hit the ball 12 ___ 40
times
or 30 of her times at bat Therefore Joan has the
greater experimental probability and is more likely to
get a hit next time
9 Gabbyrsquos experimental probability of hitting an ace
is 4 ___ 10
or 2 __ 5 Gabby could serve 16 aces in her next
40 serves because 2 __ 5 of 40 is 16
10 The experimental probability her dog wonrsquot want to
go outside is 5 ___ 12
or about 417
P(outside) + P(not outside) = 1
7 ___ 12
+ P(not outside) = 1
P(not outside) = 5 ___ 12
or 417
Focus on Higher Order Thinking
11 She did not add 40 and 60 to find the total number
of trials P(heads) = 40 ____ 100
12 Sample answer coin toss Heads represents male
and tails represents female Toss the coin 50 times
and use the results to make a prediction
13 Sample answer Make an index card to represent
each coin then pick one card at random No since
the coins are different sizes they do not each have
the same probability of getting pulled out of my
Copyright copy by Houghton Mifflin Harcourt 81 All rights reserved
LESSON 123
Your Turn
1 P(coffee + small) = number of coffee + small
_____________________ total number of orders
= 60 ____ 400
= 3 ___ 20
= 15
3 P(goId + 20 in) = number of gold + 20 in
_________________________ total number of necklaces sold
= 12 ___ 75
or 4 ___ 25
Guided Practice
1 P(female + age 22ndash39)
= number of female + age 22ndash39
__________________________ total number of patients
= 50 ____ 400
or 1 __ 8
2 Sample answer There are six possible outcomes
standard with vacuum standard with no vacuum
deluxe with vacuum deluxe with no vacuum
superior with vacuum and superior with no vacuum
Students could write the outcomes on six index
cards and put them in a box Then they can draw a
card 50 times record the results and find the
experimental probability that a customer chooses a
deluxe wash with no vacuum by dividing the
frequency of this compound event by 50 the total
number of trials
3 Find the number of occurrences of the compound
event and divide it by the total number of trials
Independent Practice
4 Divide the number of 2 piece + salad orders 33 by
the total number of orders 330
P = number of 2 piece + salad
______________________ total number of orders
= 33 ____ 330
= 1 ___ 10
5 P = number of red notebooks + 150 pages
_______________________________ total number of notebooks sold
= 60 ____ 400
= 3 ___ 20
6 P(red notebook) = number of red notebooks _____________________ total number of notebooks
= 55 + 60 + 23
____________ 400
= 138 ____ 400
= 69 ____ 200
7 12 the total is the product of 3 page-count choices
and 4 color choices
8 She left out the 53 students that read 150 pages
P(7th grade + 100 pages) = 85 ____ 250
= 17 ___ 50
9 Sample answer 8th grade the results table
suggests 8th grade students are the least likely to
have read 150 pages compared to students in 6th or
7th grade
Focus on Higher Order Thinking
10 Greater heads occurs on about half the occasions
that you roll a 6 so the compound event is half as
likely
11 Sample answer For 2 outcomes he could use even
and odd numbers For 3 outcomes he could use
1 or 2 3 or 4 and 5 or 6 For 6 outcomes he could
use each number once
12 P(male + open toe) = 11 ____ 300
P(male has open toe) = 11 ____ 150
No the first scenario
includes females and the second does not
13 No because coins are fair and the probabilities do
not appear to be equally likely
14 Sample answer On a coin heads = male and
tails = female On a number cube (1 or 2) = 6th
grade (3 or 4) = 7th grade and (5 or 6) = 8th
grade Toss the coin and roll the number cube 50
times each Record the number of outcomes that are
heads and 3 or 4
LESSON 124
Your Turn
1 024 times 550 =132 customers
2 No About 371 of the emails out of 12372 will come
back undelivered because 003 times 12372 asymp 371 The
editorrsquos prediction is too high
3 024 times 350 = 84 customers Yes because 107
customers buying two or more pairs would be more
than only 84 customers
Guided Practice
1 030 times 50 = 15 times
2 015 times 365 asymp 55 days
3 No about 1009 of the candles out of 16824 will be
returned because 006 times 16824 asymp 1009
A prediction of 812 is too low
4 No about 746 toys out of 24850 will be defective
because 003 times 24850 asymp 746 A prediction of 872 is
too high
5 98 ____ 100
= x ___ 40
= 39 ___ 40
or 39 times
No if she were late 6 out of 40 times the rate of
being on time would be only 85 in which case the
light-railrsquos claim of 98 is too high
6 18 ____ 100
= x _____ 5000
= 900 _____ 5000
or 900 students Yes the
collegersquos claim is close to the number actually
accepted
times04
times04
times50
times50
Copyright copy by Houghton Mifflin Harcourt 82 All rights reserved
7 Solve a proportion using the experimental probability
to find an expected number of events to happen
Make a prediction based on the expected number of
events
Independent Practice
8 4 ____ 100
= x ____ 200
= 8 ____ 200
or 8 students More students
moved than expected because 12 is more than 8
9 Yes 6th grade 2 ____ 100
= x ____ 250
= 5 ____ 250
or 5 students
7th grade 4 ____ 100
= x ____ 200
= 8 ____ 200
or 8 students
8th grade 8 ____ 100
= x ____ 150
= 12 ____ 150
or 12 students
Since 5 + 8 + 12 = 25 the values in the table
support his claim of 30 students
10 6 ____ 100
= x ____ 300
= 18 ____ 300
or 18 seats If an airplane is
overbooked with 310 passengers only 291 are
expected to show up since 310 times 94 asymp 291
11 006 times 600 = 36 clients If 40 clients did not pay it
would be slightly more than average
12 080 times 20 = 16 team members The coachrsquos claim is
not accurate because the average number of
students at practice is 144 ____ 8 = 8
13 He set up the fraction incorrectly it should be
1 ___ 30
= x ____ 180
Focus on Higher Order Thinking
14 1 __ 2 of 12 = 6 normal rejection rate
500 times 6 = 30 transactions rejected by a
normal gas pump
15 098 times 15000 = 14700 on-time flights Sample
answer No one week of data could be misleading
and not representative of the yearly on-time prob-
ability (because it ignores bad weather etc)
16 Sample answer No They could expect to get 96
responses with the old letter since
4 ____ 100
= x _____ 2400
= 96 _____ 2400
or 96 letters Therefore the
new letter received fewer responses
MODULE 12
Ready to Go On
1 H1 H2 T1 T2
2 6 ___ 10
= 3 __ 5
3 13 ___ 20
4 3 of the 7 total trials resulted in a sum more than 5
Therefore the experimental probability is 3 __ 7
5 I would predict he would reach first base 24 times
because 3 ___ 10
= x ___ 80
= 24 ___ 80
or 24 times
6 You can use the experimental probability based on
observation or simulation to set up a proportion and
use the proportion to predict a value
times15
times15
times24
times24
times2
times2
times3
times3
times2
times2
times25
times25
times8
times8
Copyright copy by Houghton Mifflin Harcourt 83 All rights reserved
MODULE 13 Theoretical Probability and
Simulations
Are You Ready
075
1 4 ⟌ _
300
_ -2 80
20
_ -20
0
075 = 75
04
2 5 ⟌ _
20
_ -2 0
0
04 = 40
09
3 10 ⟌ _
90
_ -9 0
0
09 = 90
035
4 20 ⟌ _
700
_ -6 00
1 00
_ -1 00
0
035 = 35
0875
5 8 ⟌ _
7000
_ thinsp-6 400
600
_ -560
40
_ -40
0
0875 = 875
005
6 20 ⟌ _
100
_ -1 00
0
005 = 5
076
7 25 ⟌ _
1900
_ -17 50
1 50
_ -1 50
0
076 = 76
046
8 50 ⟌ _
2300
_ -20 50
3 00
_ -3 00
0
046 = 46
9 1 - 1 __ 5 = 5 __
5 - 1 __
5
= 4 __ 5
10 1 - 2 __ 9 = 9 __
9 - 2 __
9
= 7 __ 9
11 1 - 8 ___ 13
= 13 ___ 13
- 8 ___ 13
= 5 ___ 13
12 1 - 3 ___ 20
= 20 ___ 20
- 3 ___ 20
= 17 ___ 20
13 8 ___ 15
times 5 __ 8 =
18 ___ 315
times 5 1 ___
8 1
= 1 __ 3
14 2 __ 9 times 3 __
4 =
12 __ 39
times 3 1 ___
4 2
= 1 __ 6
15 9 ___ 16
times 12 ___ 13
= 9 ___ 416
times 12 3 _____
13
= 27 ___ 52
16 7 ___ 10
times 5 ___ 28
= 17 ___
210 times 5
1 ____
28 4
= 1 __ 8
LESSON 131
Your Turn
2 The probability of an event is the ratio of the number
of ways the event can occur to the total number of
equally likely outcomes Therefore
P(rolling a 3 or 4) =
number of sides with 3 or 4 ________________________ total number of sides on cube
= 2 __ 6 = 1 __
3
3 The total number of outcomes in the sample space
is the denominator of the formula for theoretical
probability
Copyright copy by Houghton Mifflin Harcourt 84 All rights reserved
Guided Practice
1
Basket A Basket B
Total number of outcomes5 + 3 + 8
= 16
7 + 4 + 9
= 20
Number of red balls 3 4
P(win) =
Number of red balls
_____________________ Total number of outcomes
3 ___
16 4 ___
20 = 1 __
5
2 To compare the two probabilities of 1 __ 5 and 3 ___
16 use
the least common denominator of 80
1 __ 5 = 16 ___
80
3 ___ 16
= 15 ___ 80
Therefore 16 ___ 80
gt 15 ___ 80
so 1 __ 5 gt 3 ___
16
Choosing Basket B gives you a better chance of
winning
3 There are a total of 6 odd sections The total number
of sections (odd and even) is 11
P(odd) = number of odd sections ____________________ total number of sections
= 6 ___ 11
4 There are a total of 5 even sections The total
number of sections (odd and even) is 11
P(even) = number of even sections ____________________ total number of sections
= 5 ___ 11
5 The total number faces on a number cube is 6 and
rolling either a 3 or 4 is equal to 2 possibilities
P(rolling a 3 or 4) = number of sides with 3 or 4 ________________________ total number of sides on cube
= 2 __ 6 = 1 __
3
6 Sample answer No but it might be reasonably
close
7 Divide the number of ways the event can occur
by 20
Independent Practice
8 P(yellow) = number of yellow sections
_____________________ total number of sections
= 2 __ 6
= 1 __ 3 033 or 33
9 P(blue or green) = number of blue or green sections
___________________________ total number of sections
= 8 ___ 12
= 2 __ 3 067 or 67
10 P(cherry) = number of cherry cough drops
_________________________ total number of cough drops
= 4 ___ 14
= 2 __ 7 029 or 29
11 P(black card) = number of black cards __________________ total number of cards
= 26 ___ 52
= 1 __ 2 050 or 50
12 P(lime) = number of limes ________________________ total number of pieces of fruit
= 12 - 5 ______ 12
= 7 ___ 12
058 or 58
13 There are a total of 20 DVDs There are 12 DVDs
that are not comedies (5 science fiction plus
7 adventure)
P(not a comedy)
= number of DVDs which are not comedies _________________________________ total number of DVDs
= 5 + 7 _________
5 + 7 + 8 = 12 ___
20
= 3 __ 5 060 or 60
14 There are a total of 6 faces on a number cube There
are 2 faces (3 and 4) that are greater than 2 and
less than 5 which means 2 possibilities
P(greater than 2 and less than 5)
= number of sides with 3 and 4 ________________________ total number of sides on cube
= 2 __ 6
= 1 __ 3 033 or 33
15 9 represents the ways the event can occur
13 represents the number of equally likely outcomes
16 There are a total 16 coins and there are 6 coins that
are greater than 5 cents Therefore
P(coin worth more than 5 cents)
= number of coins worth more than 5 cents _________________________________ total number of coins
= 6 ___ 16
or 3 __ 8
The event is choosing a dime or a quarter and 6 of
the 16 coins are dimes or quarters
Focus on Higher Order Thinking
17 Sample answer Riley divided the number of petunia
seeds by the number of begonia seeds rather than
the total number of seeds The correct probability is
5 ______ 5 + 15
= 5 ___ 20
= 1 __ 4
times16
times16
times5
times5
Copyright copy by Houghton Mifflin Harcourt 85 All rights reserved
18 a The total number of students in the club is 35
There are 20 seventh graders Therefore
P(seventh grader) =
number of seventh graders
______________________ total number of students
= 20 ___ 35
= 4 __ 7
There are 15 eighth graders in the club Therefore
P(eighth grader) =
number of eighth graders
_____________________ total number of students
= 15 ___ 35
= 3 __ 7
Because 4 __ 7 gt 3 __
7 choosing a seventh grader is
more likely
b No each student has the same probability of
being selected 1 ___ 35
19 Sample answer The number of trials is twice the
number of marbles in the jar If the probabilities for
each color were the same the number of times that
color was drawn would be twice the number of
marbles with that color in the jar
20 Red The theoretical probability of choosing red is
P(red) = number of red marbles ___________________ total number of marbles
= 8 ___ 20
The experimental probability of choosing red is
14 ___ 40
or 7 ___ 20
Therefore the difference in the theoretical probability
and experimental probability of choosing a red
marble is 8 ___ 20
- 7 ___ 20
= 1 ___ 20
For blue the theoretical probability is
P(blue) = number of blue marbles ____________________ total number of marbles
= 10 ___ 20
The experimental probability is 16 ___ 40
= 8 ___ 20
Therefore the difference in the theoretical probability
and experimental probability of choosing a blue
marble is 10 ___ 20
- 8 ___ 20
= 2 ___ 20
= 1 ___ 10
For yellow the theoretical probability is
P(yellow) = number of yellow marbles
_____________________ total number of marbles
= 2 ___ 20
The experimental probability is 10 ___ 40
= 5 ___ 20
Therefore the difference in the theoretical probability
and experimental probability of choosing a yellow
marble is 5 ___ 20
- 2 ___ 20
= 3 ___ 20
Choosing a red marble has the smallest difference
between theoretical and experimental probability
LESSON 132
Your Turn
3 P(ham sandwich) =
number of combinations containing ham
_________________________________ total number of sandwich combinations
= 4 ___ 12
= 1 __ 3
4 P(sandwich containing Swiss cheese) =
number of combinations containing Swiss
__________________________________ total number of sandwich combinations
= 6 ___ 12
= 1 __ 2
5 To find the sample space make lists of possible
codes First make a list of codes that start with 0
and have 0 as the second digit
0 0 0 0
0 0 0 1
0 0 1 0
0 0 1 1
List of codes that start with 0 and have 1 as the
second digit
0 1 0 0
0 1 0 1
0 1 1 0
0 1 1 1
List of codes that start with 1 and have 0 as the
second digit
1 0 0 0
1 0 0 1
1 0 1 0
1 0 1 1
List of codes that start with 1 and have 1 as the
second digit
1 1 0 0
1 1 0 1
1 1 1 0
1 1 1 1
In total the number of possible outcomes is 16
There are six codes with exactly two 0s
0 0 1 1
0 1 0 1
0 1 1 0
1 0 0 1
1 0 1 0
1 1 0 0
This means the number of outcomes for a code with
exactly two 0s is 6 Therefore
P(Code exactly two 0s)
= number of favorable outcomes ____________________________ total number of possible outcomes
= 6 ___ 16
= 3 __ 8
Copyright copy by Houghton Mifflin Harcourt 86 All rights reserved
Guided Practice
1
1 2 3 4 5 6
11 sdot 1
= 1
1 sdot 2
= 2
1 sdot 3
= 3
1 sdot 4
= 4
1 sdot 5
= 5
1 sdot 6
= 6
22 sdot 1
= 2
2 sdot 2
= 4
2 sdot 3
= 6
2 sdot 4
= 8
2 sdot 5
= 10
2 sdot 6
= 12
33 sdot 1
= 3
3 sdot 2
= 6
3 sdot 3
= 9
3 sdot 4
= 12
3 sdot 5
= 15
3 sdot 6
= 18
44 sdot 1
= 4
4 sdot 2
= 8
4 sdot 3
= 12
4 sdot 4
= 16
4 sdot 5
= 20
4 sdot 6
= 24
55 sdot 1
= 5
5 sdot 2
= 10
5 sdot 3
= 15
5 sdot 4
= 20
5 sdot 5
= 25
5 sdot 6
= 30
66 sdot 1
= 6
6 sdot 2
= 12
6 sdot 3
= 18
6 sdot 4
= 24
6 sdot 5
= 30
6 sdot 6
= 36
2 There are 15 entries in the table that are multiples
of 4 The total number of entries in the table is 36
P(multiple of 4) = number of multiples of 4
_________________________ total number of entries in table
= 15 ___ 36
3 There are 23 entries in the table that are less than
13 The total number of entries is 36
P(less than 13) = number of entries less than 13 _________________________ total number of entries in table
= 23 ___ 36
4 H
HHH HHT
H
H
Coin 1
List
Coin 2
Coin 3 T
T
HTH HTT
H T
T
H
H T
THH THT
T
H T
TTH TTT
Coin 1
List
Coin 2
Coin 3
5 Count the total number of outcomes in the list 8
6 The only way to get three tails is TTT
7 P = number of outcomes with 3 tails __________________________ total number of outcomes
= 1 __ 8
8 There are 3 way(s) to obtain exactly two heads
HHT HTH THH
P = number of outcomes with exactly 2 heads
__________________________________ total number of possible outcomes
= 3 __ 8
9 You need to know the number of equally likely
outcomes in the sample space
Independent Practice
10
Checkered
Red
Checkered
Red
Blue
Black
Checkered
Red
Checkered
Red
Blue
Black
Checkered
Red
Checkered
Red
Blue
Black
Shirt Pants Shoes
Yellow
Red
Green
11 There are 6 combinations that include red shoes
The total number of combinations is 12 Therefore
P(red shoes) = number of combinations with red shoes ________________________________ total number of combinations
= 6 ___ 12
= 1 __ 2
12 There are four combinations that do not include red
Shirt Pants Shoes
Green Blue Checkered
Green Black Checkered
Yellow Blue Checkered
Yellow Black Checkered
P(no red) = number of outfits with no red _______________________ total number of outfits
= 4 ___ 12
= 1 __ 3
13 Let the other three band members be A B and C
The list of possible combinations is
Rhee Pamela
Rhee A
Rhee B
Rhee C
Pamela A
Pamela B
Pamela C
A B
A C
B C
There is a total of 10 combinations Of these only 1
has Rhee and Pamela so
P(Rhee and Pamela)
= Rhee and Pamela ________________________ total number of combinations
= 1 ___ 10
Copyright copy by Houghton Mifflin Harcourt 87 All rights reserved
14 The sample space can be found from adding all
possible combinations of the two numbers
1 2 3 4 5 6
11 + 1
= 2
1 + 2
= 3
1 + 3
= 4
1 + 4
= 5
1 + 5
= 6
1 + 6
= 7
22 + 1
= 3
2 + 2
= 4
2 + 3
= 5
2 + 4
= 6
2 + 5
= 7
2 + 6
= 8
33 + 1
= 4
3 + 2
= 5
3 + 3
= 6
3 + 4
= 7
3 + 5
= 8
3 + 6
= 9
44 + 1
= 5
4 + 2
= 6
4 + 3
= 7
4 + 4
= 8
4 + 5
= 9
4 + 6
= 10
55 + 1
= 6
5 + 2
= 7
5 + 3
= 8
5 + 4
= 9
5 + 5
= 10
5 + 6
= 11
66 + 1
= 7
6 + 2
= 8
6 + 3
= 9
6 + 4
= 10
6 + 5
= 11
6 + 6
= 12
There is a total of 36 possible sums Of these there
are 10 less than 6
P(sum is less than 6)
= number of sums less than 6 ____________________________ total number of possible outcomes
= 10 ___ 36
= 5 ___ 18
15 The sample space can be found from a tree
diagram
Khakis
Shorts
Shirt Pants Shoes
Collared Jeans
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Khakis
Shorts
T-shirt Jeans
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Total number of possible outcomes is 18 the
number of combinations which include jeans but
not sneakers is 4 Therefore
P(jeans but not sneakers)
= number of outfits with jeans no sneakers
_________________________________ total number of possible outcomes
= 4 ___ 18
= 2 __ 9
16 For each chair lift there are 6 possible trails So you
can multiply the number of choices of chair lifts (3)
by the number of trails (6)
17 Because there are 3 choices for the first item and
2 for the second there are 3 middot 2 = 6 possible
outcomes
18 There is a total of 30 possible shoe sizes Of these
the number of red shoes size 9 or larger is 7
Therefore
P(red and size 9 or larger) =
number of red shoes size 9 or larger
______________________________ total number of possible outcomes
= 7 ___ 30
Focus on Higher Order Thinking
19 Sondra orders one item from each column There
are 4 main dishes 4 vegetables and two sides so
the sample space is 4 sdot 4 sdot 2 = 32 The possible
outcomes of Sondrarsquos order are shown in the tree
diagram
Carrots
Sweet potato
Pasta
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Carrots
Sweet potato
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Carrots
Sweet potato
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Carrots
Sweet potato
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Salmon
Beef
Pork
Copyright copy by Houghton Mifflin Harcourt 88 All rights reserved
There are 8 total number of outcomes that include
salmon Therefore
Sondra P(salmon) = 8 ___ 32
= 1 __ 4
Gretchen orders a main dish and a vegetable There
are 4 main dishes and 4 vegetables so the sample
space is 4 sdot 4 = 16 The possible outcomes of
Gretchenrsquos order are shown in the tree diagram
Carrots
Sweet potato
PastaPeas
Asparagus
Carrots
Sweet potato
Peas
Asparagus
Carrots
Sweet potato
Peas
Asparagus
Carrots
Sweet potato
Peas
Asparagus
Salmon
Beef
Pork
There are 4 total number of outcomes that include
salmon Therefore
Gretchen (salmon) = 4 ___ 16
= 1 __ 4
Because the probabilities for Sondra and Gretchen
are equal neither has a greater probability of getting
a meal that includes salmon
20 a For possible two-digit codes consider first codes
that begin with 1 12 13 14 15 There are a total
of 4 possible codes This pattern continues for
each of the 5 digits and therefore we have a total
of 4 + 4 + 4 + 4 + 4 = 20 possible two-digit
codes (four codes each that begin with each of
the numbers 1ndash5)
For possible three-digit codes there are 12
possible codes that begin with 1 and so there are
12 possible codes for each of the numbers 1ndash5
making a total of 5 sdot 12 = 60 possible three-digit
codes
We can predict the number of possible five-digit
codes because we know there are 60 possible
three-digit codes and for each of these there are
only two digits that can be added to the end of
each code to make them five-digit codes These
are the digits that were not used in the three-digit
code and they have two possible orders for a
total of 60 sdot 2 = 120 possible five-digit codes
As a concrete example again consider the three-
digit codes that begin with 1 Tacking on the digits
which are not included in these three-digit codes
in both orders we have 12345 12354 12435
12453 12534 12543 13245 13254 13425
13452 13524 13542 14235 14253 14325
14352 14523 14532 15234 15243 15324
15342 15423 15432 If we do the same for the
three-digit codes beginning with 2ndash5 we will find
the 120 possible five-digit codes
b Now that the numbers can repeat for two-digit
codes take the 20 codes from before and add five
more codes (11 22 33 44 55) which makes a
total of 25 two-digit codes
For three-digit codes take the 60 codes from
before and add the 5 codes that have all digits
the same plus codes which have two digits
which are repeats To find these consider first the
codes with the first two digits the same 112 113
114 115 221 223 224 225 331 332 334 335
441 442 443 445 551 552 553 554 There
are 20 possible codes There are also 20 possible
codes with the last two digits the same Finally
consider the codes where the first and last digits
are the same For the repeated digit 1 we have
121 131 141 151 or 4 possible codes For each
of the digits 1ndash5 we have 4 possible codes for a
total of 4 sdot 5 = 20 Therefore the overall total
60 + 5 + 20 + 20 + 2 = 125 three-digit codes
To solve for how many possible 5 digit codes
there are notice a pattern in the codes For
two-digit codes the total possible codes is the
number of possible digits raised to the power
equal to the number of digits in the code or
52 = 25 For three-digit codes the number of
possible digits is the same and the number
of digits in the code is 3 so we have 53 = 125
Following this pattern there are 55 = 3125
possible five-digit codes
c Sample answer The better choice is to have the
digits repeat there are more unique codes with
repeated digits than without so it would be more
difficult for someone to guess a code for a locker
LESSON 133
Your Turn
1 There are 4 numbers less than 5 on a standard
number cube There are 6 possible outcomes so
P(number less than 5) = 4 __ 6 = 2 __
3
The number of events is 250 Therefore
P(number less than 5) times Number of events =
2 __ 3 times 250 = 16666 or about 167 times
Copyright copy by Houghton Mifflin Harcourt 89 All rights reserved
2 Set up a proportion The probability of getting
heads is 1 __ 2
1 __ 2 = x ___
18
1 __ 2 = x ___
18
x = 9
about 9 times
3 There are 17 total marbles and 8 are red Therefore
P(red) = 8 ___ 17
P(not red) = 1 - 8 ___ 17
= 9 ___ 17
It is more likely that he picks a marble that is not red
4 No Sample answer There is a total of 71 bills in the
bag and there are 11 bills worth $6 or more
Therefore
P(bill worth $6 or more) = 11 ___ 71
This is about a 15 probability so it is not likely you
will win enough to pay for your ticket
Guided Practice
1 An equally likely chance means that the probabilities
of being assigned to each crew are the same and
since there are three possibilities each has a
probability of 1 __ 3
Apartment 1 __ 3 Condo 1 __
3 House 1 __
3
The probability of being assigned to house crew is 1 __ 3
Set up and solve a proportion
1 __ 3 = x ___
18
1 __ 3 = x ___
18
x = 6
This means that Bob can expect to be assigned to
the house crew about 6 times out of 18
2 Since half of the ticket holders will receive a prize
this means that 300 divide 2 = 150 people will receive a
prize Because they are equally likely to receive one
of three prizes the probability of winning each of the
prizes is 1 __ 3 so the probability of winning a movie
ticket is 1 __ 3 The number of events is 150 Therefore
P(movie ticket) times Number of events = 1 __ 3 times 150 =
50 or 50 people are predicted to win a movie ticket
3 The total number of students in Mr Jawaranirsquos class
is 28 The probabilities of picking a student at
random with a certain eye color are
P(hazel) = 9 ___ 28
P(brown) = 10 ___ 28
P(blue) = 7 ___ 28
P(green) = 2 ___ 28
The event with the greatest probability is choosing a
person with brown eyes
4 You can find and compare probabilities Or you can
use probability to set up and solve a proportion or
an equation that relates the probability to the
unknown quantity
Independent Practice
5 The total number of marbles in the bag is 9 The
number of white or gray marbles is 3 Therefore
P(white or gray) = 3 __ 9 = 1 __
3
The number of events is 45 The equation to make a
prediction is then
P(white or gray) times Number of events = 1 __ 3 times 45 = 15
You can expect to get 15 white or gray marbles
6 A spinner which has an equal likelihood to land on
green or yellow means that the number of green and
yellow sections must be equal More likely to land on
red means that there must be more red sections
than yellow or green A Sample answer is
Y GRR
R R
RR
7 Because half the deck is red the probability of
drawing a red card is 1 __ 2 Because there are three
face cards for each of four suits there are 3 sdot 4 = 12
face cards and the probability of drawing a face
card is 12 ___ 52
To compare 1 __ 2 and 12 ___
52 use the least
common denominator of 52 so that 1 __ 2 = 26 ___
52 Given
that 12 ___ 52
lt 26 ___ 52
the probability of drawing a red card
is higher than of drawing a face card and it is more
likely that Dawn draws 2 red cards
8 The total number of aces in a deck is 4 Therefore
P(ace) = 4 ___ 52
= 1 ___ 13
The number of events is 39 The equation to make a
prediction is then
P(ace) middot Number of events = 1 ___ 13
times 39 = 3
He is predicted to draw an ace 3 times
9 The total number of red cards is 26 Therefore
P(red card) = 26 ___ 52
= 1 __ 2
The number of events is 1000 The equation to
make a prediction is then
P(red card) sdot Number of events = 1 __ 2 sdot 1000 = 500
The player is predicted to turn over a red card as the
first card 500 times
10 The sample space can be found from adding all
possible combinations of the two numbers
times6
times6
times9
times9
Copyright copy by Houghton Mifflin Harcourt 90 All rights reserved
1 2 3 4 5 6
1 2 3 4 5 6 7
2 3 4 5 6 7 8
3 4 5 6 7 8 9
4 5 6 7 8 9 10
5 6 7 8 9 10 11
6 7 8 9 10 11 12
There is a total of 36 possible sums Of these there
are 5 ways to roll a sum of 8 and 2 ways to roll a
sum of 11 The probabilities are
P(sum of 8) = 5 ___ 36
P(sum of 11) = 2 ___ 36
Because the probability of rolling a sum of 8 is
greater than that of rolling a sum of 11 ( 5 ___ 36
gt 2 ___ 36
) John is more likely to win
11 There are 5 possible numbers greater than 15 so
P(greater than 15) = 5 ___ 20
= 1 __ 4
The number of events is 180 The equation to make
a prediction is then
P(greater than 15) times Number of events =
1 __ 4 times 180 = 45
The chosen number will be greater than 15 for 45
days in the school year
12 The sample space for a standard cube is 36 and
there are 3 combinations that will have a sum of 4
so P(sum of 3) = 3 ___ 36
= 1 ___ 12
The number of events is 36 The equation to make a
prediction is then
P(sum of 3) times Number of events = 1 ___ 12
middot 36 = 3
Eben is predicted to roll a sum of 4 a total of 3 times
13 Sample answer No Every time you flip a coin the
probability of heads is 1 __ 2 but in reality you could flip
a coin many times and have it land heads up every
time
14 Sample answer A bag of marbles contains red and
blue marbles that are different sizes Since it is easy
to feel the difference between the two colors all of
the outcomes are not equally likely You cannot make
a prediction using theoretical probability
Focus on Higher Order Thinking
15 Sample answer What is the theoretical probability
that the coin lands on heads and you pick a marble
that is not green
The probability that the coin lands on heads is 1 __ 2
and the probability that the picked marble is not
green is 3 + 9 _________
3 + 8 + 9 = 12 ___
20 The product of these two
probabilities is 1 __ 2 times 12 ___
20 = 12 ___
40
16 Sample answer It is much more likely that he rolls a
5 or the coin lands on heads
The probability that Horace rolls a 5 and the coin
lands on heads is given by
P(5 and heads) = 1 __ 2 times 1 __
6 = 1 ___
12
In the case where Horace rolls a 5 or the coin lands
on heads the probability is given by
P(5 or heads) = 1 __ 6 + 1 __
2 - 1 __
6 times 1 __
2 = 7 ___
12
17 Yes but only theoretically because in reality nothing
can occur 05 times Sample answer The probability
that a flipped coin lands heads up is 1 __ 2 so in 75 flips
you can expect heads about 75 ___ 2 or 375 times
LESSON 134
Your Turn
1 Sample answer (data and percent will vary)
Trial Numbers generated 3 Males first
1 0 0 1 No
2 0 1 No
3 1 No
4 0 1 No
5 1 No
6 0 0 0 1 Yes
7 0 0 1 No
8 0 1 No
9 1 No
10 0 0 0 0 1 Yes
For these data the experimental probability that the
elephant gives birth to 3 male calves before having a
female calf is 2 ___ 10
or 20
2 Sample Answer (data and percent will vary)
Trial Numbers generated Correct answers
1 1 0 1 1 0 3
2 0 1 0 0 1 2
3 0 0 0 0 1 1
4 0 0 1 1 0 2
5 1 1 1 1 1 5
6 1 0 0 0 0 1
7 1 0 1 1 0 3
8 1 0 1 0 0 2
9 0 1 1 1 1 4
10 0 0 0 0 0 0
The experimental probability that he gets at least 2
questions right is 7 ___ 10
= 70
Copyright copy by Houghton Mifflin Harcourt 91 All rights reserved
Guided Practice
1 Since there is a 30 or 3 ___ 10
chance of drought let
the numbers 1 to 3 represent years with a drought
and the numbers 4 to 10 represent years without
a drought Since we are interested in the next 4
years perform multiple trials generating 4 random
numbers each time
2
Trial Numbers generated Drought years
1 10 3 5 1 2
2 10 4 6 5 0
3 3 2 10 3 3
4 2 10 4 4 1
5 7 3 6 3 2
6 8 4 8 5 0
7 6 2 2 8 2
8 6 5 2 4 1
9 2 2 3 2 4
10 6 3 1 5 2
3 In 8 out of the 10 trials there was a drought in at
least one of the years The experimental probability
of a drought in at least 1 of the next 4 years is
8 ___ 10
= 80
4 Sample answer Generate whole numbers from
1 to 4 Let 1 to 3 represent the event occurring
and 4 represent the event not occurring
Independent Practice
5 There is only 1 trial Trial 6 where it took exactly
4 contestants to get a winner
6 Since 1 out of 10 trials resulted in exactly
4 contestants the probability is 1 ___ 10
= 10
7 The trials for which at least 4 hurricanes struck are
Trials 2 and 7 or 2 out of 10 trials Therefore the
probability is 2 ___ 10
= 20
8 It is fewer than expected based on the simulation
9 It is unlikely but it is not impossible Each of the 3
numbers could be any number from 1 to 10
However there are 10 possible first numbers 10
possible second numbers and 10 possible third
numbers or a total of 1000 possible numbers when
generating three numbers from 1 to 10 The
probability of generating three 10s is 1 _____ 1000
10 Sample answer Use the numbers 1ndash5 where 1 2
and 3 represent packs which contain a player from
Erikarsquos favorite team Generate numbers randomly
and stop when you get a 1 2 or 3
Trial Numbers generated Number of Packs
1 3 1
2 4 2 2
3 2 1
4 1 1
5 2 1
6 4 5 3 2
7 4 2 2
8 4 5 2 1
9 4 4 3 3
10 5 1 2
The average number of packs she needs to buy is
1 + 2 + 1 + 1 + 1 + 2 + 2 + 1 + 3 + 2
_________________________________ 10
= 16 ___ 10
= 1 3 __ 5
packs Since she cannot buy a fraction of a pack
she must buy 2 packs
Focus on Higher Order Thinking
11 Sample answer The probability that she makes a
shot is 375 = 3 __ 8 Use the whole numbers from 1 to
8 with 1ndash3 representing shots she makes and 4ndash8
representing shots she misses For each new trial
generate 10 random numbers Count the number
of times 1 2 or 3 appears in each trial Divide the
number of trials in which she made at least 3 shots
by the total number of trials
12 Sample answer Their simulation was not
appropriate perhaps because they chose an
incorrect model You would expect there to have
been exactly 4 heads on more of the trials and
more variation in the number of heads in general
MODULE 13
Ready to Go On
1 P(red) = number of red marbles ___________________ total number of marbles
= 12 ___________________ 12 + 12 + 15 + 9 + 12
= 12 ___ 60
= 1 __ 5 020 or 20
2 P(diamond or spade)
= number of diamonds and spades
___________________________ total number of cards
= 13 + 13
_______ 52
= 26 ___ 52
= 1 __ 2 050 or 50
3 The most likely color of marble chosen is the most
common color in this case green
Copyright copy by Houghton Mifflin Harcourt 92 All rights reserved
4 In order to find the experimental probability count
the number of trials in which 1 occurs at least once
In this case there are 4 trials that generated a 1
Therefore the experimental probability is 4 ___ 10
or
40
5 Sample answer You can find the theoretical
probability of an event and then use it to make a
prediction by setting up a proportion
Copyright copy by Houghton Mifflin Harcourt 93 All rights reserved
Independent Practice
18 a
-4
-6
-8
-2
0
2
-5 + (-3)-3 + (-5)
b No -5 + ( -3 ) is -8 and -3 + ( -5 ) is also -8
19 -3 + ( -1 ) + ( -5 ) + ( -2 ) = -11 the golferrsquos total
score is -11
20 -3 + ( -6 ) = -9 the team lost a total of 9 yards
21 -14 + ( -5 ) + ( -12 ) + ( -23 ) = -54 The total
sack yardage was -54
22 a -10 + ( -8 ) = -18
b -6 + ( -2 ) = -8
c -18 lt -8 Jonestown
23 -100 + ( -75 ) + ( -85 ) = -260
Focus on Higher Order Thinking
24 a -25 + ( -45 ) + ( -75 ) = -145 Jan withdrew
$145
b -35 + ( -55 ) + ( -65 ) = -155 Julie withdrew
$155
c Sample answer $45 $55 and $65
25 It is easier to add -80 + ( -20 ) fi rst to get -100
and then add -173 to get -273
26 Disagree there are three pairs of positive integers
1 and 7 2 and 6 and 3 and 5 and three pairs of
negative integers -1 and -7 -2 and -6 -3 and
-5 The absolute value of the sum of any of these
six pairs is 8
LESSON 12
Your Turn
7 -51 + 23
ǀ -51 ǀ - ǀ 23 ǀ = 28
-51 + 23 = -28
8 10 + ( -18 )
ǀ -18 ǀ - ǀ 10 ǀ = 8
10 + ( -18 ) = -8
9 13 + ( -13 )
ǀ 13 ǀ - ǀ -13 ǀ = 0
10 25 + ( -26 )
ǀ -26 ǀ - ǀ 25 ǀ = 1
25 + ( -26 ) = -1
Guided Practice
1 9 + ( -3 ) = 6
2 3 4 5 8 9 106 7 2 -2 + 7 = 5
-3-2-1 0 3 4 51 2 3 -15 + 4 = -11
-18 -16 -12 -10-14 4 1 + ( -4 ) = -3
-5-4-3-2 1 2 3-1 0 5 -4 + 5 = 1
6 -6 + 6 = 0
7 2 + ( -5 ) = -3
8 -3 + 7 = 4
9 -8 + 14 = 6
10 7 + ( -5 ) = 2
11 5 + ( -21 ) = -16
12 14 + ( -14 ) = 0
13 0 + ( -5 ) = -5
14 32 + ( -8 ) = 24
15 To fi nd -4 + 2 start at -4 and move 2 units to the
right to -2 To fi nd the sum -4 + ( -2 ) start at -4
and move 2 units to the left to -6
Independent Practice
16 -15 + 71 = 56
17 -53 + 45 = -8
18 -79 + 79 = 0
19 -25 + 50 = 25
20 18 + ( -32 ) = -14
21 5 + ( -100 ) = -95
22 -12 + 8 + 7 = 3
23 -8 + ( -2 ) + 3 = -7
Copyright copy by Houghton Mifflin Harcourt 2 All rights reserved
24 15 + ( -15 ) + 200 = 200
25 -500 + ( -600 ) + 1200 = 100
26 9 + ( -22 ) = -13 the team lost 13 yards
27 -55 + 275 = 220 the teamrsquos profi t was $220
28 -47 + 47 = 0 Alexrsquos new balance is $0
29 Sample answer 10 and -2 and 12 and -4
30 Bart won Bartrsquos score = 123 + ( -180 ) = -57
points Samrsquos score = 185 + ( -255 ) = -70 points
-57 gt -70 so Bart has the greater score
Focus on Higher Order Thinking
31 Start at -4 and move 3 to the right to reach -1
Start at 3 and move 4 to the left to reach -1
The sums are equivalent by the Commutative
Property of Addition
32 The weight is dropped from 4 feet above the surface
Add -12 to represent the distance the weight falls
before it hits the bottom 4 + ( -12 ) = -8 The water
is 8 feet deep
33 Sample answer A model with more positive
counters than negative counters represents a sum of
two integers whose sum is positive
34 The sign of the other integer is positive and its value
is 6 or greater Sample explanation If you start at
-5 on a number line you have to move to the right 6
or more units to get a sum that is positive
LESSON 13
Your Turn
4 -7 - 2 = -7 + ( -2 )
-7 + ( -2 ) = -9
5 -1 - ( -3 ) = -1 + 3
-1 + 3 = 2
6 3 - 5 = 3 + ( -5 )
3 + ( -5 ) = -2
7 -8 - ( -4 ) = -8 + 4
-8 + 4 = -4
Guided Practice
1 5 - 8 = -3 Start with 5 positive counters
Add 3 zero pairs and remove 8 positive counters
3 negative counters are left so the difference is -3
2 -5 - ( -3 ) = -2 Start with 5 negative counters
and remove 3 negative counters 2 negative
counters are left so the difference is -2
3 -4 - 5 = -4 + ( -5 ) = -9
0-1-2-3-4-5-6-7-8-9 4 1 - 4 = 1 + -4 = -3
0 1 2 3 4-1-2-3-4 5 8 - 11 = 8 + ( -11 ) = -3
6 -3 - ( -5 ) = -3 + 5 = 2
7 15 - 21 = 15 + ( -21 ) = -6
8 -17 - 1 = -17 + ( -1 ) = -18
9 0 - ( -5 ) = 0 + 5 = 5
10 1 - ( -18 ) = 1 + 18 = 19
11 15 - 1 = 14
12 -3 - ( -45 ) = -3 + 45 = 42
13 19 - ( -19 ) = 19 + 19 = 38
14 -87 - ( -87 ) = -87 + 87 = 0
15 To subtract an integer add its opposite Sample
example 6 - 8 = 6 + ( -8 ) = -2
Independent Practice
16 To fi nd the change to Theorsquos account subtract the
initial balance -$4 from the fi nal balance $25
25 - ( -4 ) = 25 + 4 = 29
The overall change is $29
17 To fi nd the change in elevation subtract the
beginning elevation of -225 feet from the fi nal
elevation of -127 feet
-127 - ( -225 ) = -127 + 225 = 98
The change in elevation was 98 feet
18 Subtract the low temperature -2degF from the high
temperature 90degF
90 - ( -2 ) = 92
The difference between the high and low
temperatures is 92degF
19 Subtract Cheyennersquos score at the end of her turn
from her score at the start of her turn to fi nd the
change in Cheyennersquos score during her turn
-425 - ( -275 ) = -425 + 275 = -150
The change in Cheyennersquos score is -150 points
20 a Final temperature - initial temperature = change
in temperature
Gas A -8 - ( -21 ) = -8 + 21 = 13
13degC increase
Gas B 12 - ( -12 ) = 12 + 12 = 24
24degC increase
Gas C -15 - ( -19 ) = -15 + 19 = 4
4degC increase
b Negative the fi nal temperatures will be less than
the initial temperature because the gas is cooler
So the difference in temperatures will be negative
21 Diet Chow the catrsquos weight changed by
-8 + ( -18 ) = -26 ounces with Diet Chow and
3 + ( -19 ) = -16 ounces with Kitty Diet
Focus on Higher Order Thinking
22 Sample answer Susanne owed her sister $4 Then
she borrowed $10 more How much does Susanne
owe her sister in all
23 Tom found -11 - 4 instead of -11 - ( -4 ) To
subtract -4 he should add the opposite of -4
-11 + 4 = -7
Copyright copy by Houghton Mifflin Harcourt 3 All rights reserved
24 YouranswerwillbegreaterthantheintegeryoustartedwithbecausewhenyousubtractanegativeintegeryouadditsoppositeapositiveintegerForexample-5-( -3)=-5+3=-2-2gt-5
25 -16-21-26subtract5togetthenextterm
LESSON 14
Your Turn
1 Starts-Descends+Ascends-40-13+18=-53+18 =-3535feetbelowthecaveentrance
3 Usenegativeintegersforcheckamountsanduseapositiveintegerforamountdeposited-35+( -45)+180=-80+180 =100$100increase
4 JimJim-10-18+5-12=-10-18-12+5 =-( 10+18+12)+5 =-40+5 =-35Jimrestedat-35feet(35feetbelowthesurface)Carla0-20+5-18=0+5-20-18 =0+5-( 20+18) =5-38 =-33Carlarestedat-33feet(33feetbelowthesurface)
Guided Practice
1 -15+ 9- 12= -6- 12 =-1818feetbelowsealevel
2 -23+5-7=-18-7 =-25-25degF
3 50-40+87-30=10+87-30 =97-30 =6767points
4 -6+15+15=-6+30 =24
5 9- 4- 17= 9- 21 =-12
6 50-42+10=8+10 =18
7 6+13+7-5=19+2 =21
8 65+43-11=108-11 =97
9 -35-14+45+31=-49+76 =27
10 -12+6-4=-6-4 =-10-34-3+39=-37+39 = 2 -10lt2( -12+6-4)lt( -34-3+39)
11 21-3+8=18+8 =26-14+ 31- 6= 17- 6 =11 26gt11( 21-3+8)gt( -14+31-6)
12 SampleanswerAddandsubtractfromlefttoright-5+12+10-7=7+10-7=17-7=10
Independent Practice
13 a 5-1+6-1=9
b 9isapositivescoresoitisoverpar
c 9overparislessthan15overparYesCameronbeathisbestgolfscore
14 -6+14-11=-33feetunderground
15 TheCommutativePropertydoesnotapplytosubtraction3-6+5=2and3-5+6=4
16 a -350+275+70-50=-55Leersquosfinalscoreis-55points
b 45gt-55Barry
17 a 300to400
b 75+30-12+14-8+18-30=75+18+6-12=8787customersmustleavebetween400and500
18 100-18+22-53=51$51
19 45-17-22+18=24$24
20 Carlarsquosaccountdecreased$49-18+22-53=-49andLetarsquosaccountonlydecreased$21-17-22+18=-21Carlarsquosaccounthadthegreatestdecreaseinvalue
Focus on Higher Order Thinking
21 SampleanswerTimoweshisbrother1dollarHeborrows6moredollarsfromhisbrotherHepayshisbrotherback3dollarsHowmuchdoesTimstillowehisbrother-1-6+3=-4$4
22 Nothetotalamountshecouldpayherparentsis10+12+25=47and50-47=3Soshestillneeds$3
23 SampleanswerInthecaseinwhichthefirstnumberispositivethenthesumoftheabsolutevaluesoftheothertwonumbersmustbegreaterthanthevalueofthefirstnumberSampleexample13-5-10=-2ǀ 5ǀ+ǀ 10ǀ=15whichisgreaterthan13
MODULE 1
Ready to Go On
1 -8+( -6)=-14
2 -4+( -7)=-11
3 -9+( -12)=-21
CopyrightcopybyHoughtonMifflinHarcourt 4 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U1M01indd 4 103113 206 AM
4 5 + ( -2 )
ǀ 5 ǀ - ǀ -2 ǀ = 3
5 + ( -2 ) = 3
5 -8 + 4
ǀ -8 ǀ - ǀ 4 ǀ = 4
-8 + 4 = -4
6 15 + ( -8 )
ǀ 15 ǀ - ǀ -8 ǀ = 7
15 + ( -8 ) = 7
7 2 - 9 = 2 + ( -9 )
2 + ( -9 ) = -7
8 -3 - ( -4 ) = -3 + 4-3 + 4 = 1
9 11 - ( -12 ) = 11 + 12
11 + 12 = 23
10 -15 + 9 - 4 = -6 - 4
= -10
There are 10 fewer people on the bus
11 24 + 8 - 12 - 9 = 24 + 8 - ( 12 + 9 ) = 32 - 21
= 11
There are 11 cards left in the stack
12 Sample answer Tonya owes her sister $10 and
her friend $5 By how much will her savings change
after she pays them
-10 + ( -5 ) = -15 $15 decrease
Copyright copy by Houghton Mifflin Harcourt 5 All rights reserved
MODULE 2 Multiplying and Dividing Integers
Are You Ready
1 9 times 3 = 27
2 7 times 10 = 70
3 9 times 8 = 72
4 15 times 10 = 150
5 6 times 9 = 54
6 10 times 23 = 230
7 9 times 9 = 81
8 10 times 20 = 200
9 54 divide 9 = 6
10 42 divide 6 = 7
11 24 divide 3 = 8
12 64 divide 8 = 8
13 90 divide 10 = 9
14 56 divide 7 = 8
15 81 divide 9 = 9
16 110 divide 11 = 10
17 12 + 8 divide 212 + 4
16
18 15 - ( 4 + 3 ) times 2
15 - 7 times 2
15 - 14
1
19 18 - ( 8 - 5 ) 2
18 - ( 3 ) 2
18 - 9
9
20 6 + 7 times 3 - 5
6 + 21 - 5
27 - 5
22
21 9 + ( 2 2 + 3 ) 2 times 2
9 + ( 4 + 3 ) 2 times 2
9 + ( 7 ) 2 times 2
9 + 49 times 2
9 + 98
107
22 6 + 5 - 4 times 3 divide 2
6 + 5 - 12 divide 2
6 + 5 - 6
11 - 6
5
LESSON 21
Your Turn
4 Since the numbers have opposite signs the product
will be negative
ǀ -3 ǀ times ǀ 5 ǀ = 3 times 5 = 15
-3 ( 5 ) = -15
5 Since the numbers have the same sign the product
will be positive
ǀ -10 ǀ times ǀ -2 ǀ = 10 times 2 = 20
( -10 ) ( -2 ) = 20
6 One of the factors is 0 so the product is 0
0 ( -22 ) = 0
7 Since the numbers have the same sign the product
will be positive
8 ( 4 ) = 32
Guided Practice
1 -1 ( 9 ) = -9
2 14 ( -2 ) = -28
3 ( -9 ) ( -6 ) = 54
4 ( -2 ) ( 50 ) = -100
5 ( -4 ) ( 15 ) = -60
6 -18 ( 0 ) = 0
7 ( -7 ) ( -7 ) = 49
8 -15 ( 9 ) = -135
9 ( 8 ) ( -12 ) = -96
10 -3 ( -100 ) = 300
11 0 ( -153 ) = 0
12 -6 ( 32 ) = -192
13 7 ( -75 ) = -525 -$525
14 Start at zero and move 5 units to the left 3 times
3 ( -5 ) = -15 the team lost 15 yards
15 6 ( -2 ) = -12 -12degF
16 Multiply the absolute values of the integers If both
integers have the same sign the product is positive
If they have different signs the product is negative
Independent Practice
17 No her number line shows the correct result -6
but she modeled 2 ( -3 ) instead of -2 ( 3 )
18 2 ( -3 ) = -6 he went down 6 floors
19 5 ( -4 ) = -20 $20 decrease
20 Adam descended 5 feet a total of 5 times
5 ( -5 ) = -25 Adam is 25 feet below sea level
21 7 ( -6 ) = -42 the cost of the jeans decreased by
$42 over the 7 weeks
22 9 ( -6 ) = -54 -54 ( 2 ) = -108 Casey has $108
less in his savings
23 7 ( -8 ) = -56 7 ( -5 ) = -35
-56 + ( -35 ) = -91 The savings decreased by $91
24 Sample answer Dave plays a video game in which
he loses 20 points every time he misses a goal
He misses 8 goals 8 ( -20 ) = -160 he loses
160 points
Copyright copy by Houghton Mifflin Harcourt 6 All rights reserved
25 a 3 ( 3 ) ( -3 ) = 9 ( -3 ) = -27
b 3 ( -3 ) ( -3 ) = -9 ( -3 ) = 27
c -3 ( -3 ) ( -3 ) = 9 ( -3 ) = -27
d 3 ( 3 ) ( 3 ) ( -3 ) = 9 ( 3 ) ( -3 ) = 27 ( -3 ) = -81
e 3 ( 3 ) ( -3 ) ( -3 ) = 9 ( -3 ) ( -3 ) = -27 ( -3 ) = 81
f 3 ( -3 ) ( -3 ) ( -3 ) = -9 ( -3 ) ( -3 ) = 27 ( -3 ) = -81
g When a product of integers has an odd number of
negative factors like -3 ( -3 ) ( -3 ) = -27 and
3 ( 3 ) ( 3 ) ( -3 ) = -81 the sign of the product is
negative
When a product of integers has an even number
of negative factors like ( 3 ) ( -3 ) ( -3 ) = 27 and
3 ( 3 ) ( -3 ) ( -3 ) = 9 ( -3 ) ( -3 ) = 81 the sign of the
product is positive
Focus on Higher Order Thinking
26 -1 ( 3 ) ( 1 ) 1 ( -3 ) ( 1 ) -1 ( -3 ) ( -1 )
27 Unless one of the factors is 0 whenever the factors
have opposite signs the product will be less than or
equal to both of the two factors
28 The sign of the product is equal to the sign of the
integers The sign of the product of the first two
integers will always be positive Multiplying this
product by the remaining factor will make a positive
product if the factor is positive negative if it is
negative
LESSON 22
Your Turn
2 Since only the dividend is zero the quotient is 0
0 divide ( -6 ) = 0
3 Since the numbers have opposite signs the quotient
will be negative
38 divide ( -19 ) = -2
4 Since the numbers have the same sign the quotient
will be positive
-13 divide ( -1 ) = 13
5 Yolanda received the same number of penalties in
each game -25 divide ( -5 ) = 5 and -35 divide ( -7 ) = 5
Guided Practice
1 -14 ____ 2 = -7
2 21 divide ( -3 ) = -7
3 26 ____ -13
= -2
4 0 divide ( -4 ) = 0
5 -45 ____ -5 = 9
6 -30 divide ( 10 ) = -3
7 -11 ____ -1
= 11
8 -31 divide ( -31 ) = 1
9 0 ___ -7 = 0
10 -121 _____ -11
= 11
11 84 divide ( -7 ) = -12
12 500 ____ -25
= -20
13 -6 divide ( 0 ) = undefined any number divided by 0 is
undefined
14 -63 ____ -21
= 3
15 -40 divide ( 4 ) = -10 $10
16 -22 divide ( 11 ) = -2 2 points
17 -75 divide ( -15 ) = 5 5 targets
18 -99 divide ( -9 ) = 11 11 times
19 In both cases if the signs of the initial numbers are
the same the answer will be positive If the signs are
different the answer will be negative
Independent Practice
20 -24 divide ( 12 ) = -2 $2
21 Elisa made a greater number of withdrawals She
made -140 divide ( -20 ) = 7 withdrawals Francis made
-270 divide ( -45 ) = 6 withdrawals and 7 gt 6
22 a -2 - 10 = -12 the temperature decreased 12degF
b -12 divide ( 12 ) = -1 decreased by 1degF each hour
23 The first part the rate of change for the first part
is -200 ft _______ 10 min
= -20 ftmin and the rate of change for
the second part is -300 ft _______ 20 min
= -15 ftmin
20 ftmin gt 15 ftmin
24 Sample answer A football team lost 50 yards due to
5 penalties If the team lost the same number of
yards for each penalty what was the change in field
position for each penalty
25 Sample answer a = - 20 and b = 5 less than
-20 divide 5 = -4 and -20 times 5 = -100
-100 lt -4
26 True if the integers have the same sign the product
and quotient are positive if they have different signs
negative
27 False division by 0 is undefined for any dividend
Focus on Higher Order Thinking
28 a 100 divide 25 = 4 4 points
b -16 divide ( -4 ) = 4 Fred answered 4 questions
incorrectly
29 a divide ( -3 ) = 8
a = -24
8 divide b = -4
a divide b = -24 divide ( -2 ) = 12
Copyright copy by Houghton Mifflin Harcourt 7 All rights reserved
30 Dividing integers with the same sign results in a
positive number Since the original two integers are
negative the quotient is greater than both of these
integers
LESSON 23
Your Turn
1 Reggie earned 110 points
3 ( -30 ) + 200 = -90 + 200
= 110
2 -6 ( 13 ) - 21 = -78 - 21
= -99
4 ( -12 ) divide 6 + 2 = -2 + 2
= 0
5 -87 divide ( -3 ) -9 = 29 - 9
= 20
6 40 divide ( -5 ) + 30 = -8 + 30
= 22
7 -39 divide 3 -15 = -13 - 15
= -28
8 Amber moved 3 ( -3 ) + 5 = -4 or 4 places back
Will moved 2 ( -4 ) + 3 = -5 or 5 places back Will
moved further back
9 ( -10 ) divide 2 - 2 = -5 - 2 = -7
( -28 ) divide 4 + 1 = -7 + 1 = -6
10 42 divide ( -3 ) + 9 = -14 + 9 = -5
( -36 ) divide 9 - 2 = -4 - 2 = -6
Guided Practice
1 -6 ( -5 ) + 12 = 30 + 12
= 42
2 3 ( -6 ) - 3 = -18 - 3
= -21
3 -2 ( 8 ) + 7 = -16 + 7
= -9
4 4 ( -13 ) + 20 = -52 + 20
= -32
5 -4 ( 0 ) - 4 = 0 - 4
= -4
6 -3 ( -5 ) - 16 = 15 - 16
= -1
7 7 ( -5 ) + 20 = -35 + 20
= -15
15 dollars less
8 7 ( -10 ) + ( -100 ) = -70 + ( -100 )
= -170
170 fewer points
9 6 ( -4 ) + 10 = -24 + 10
= -14
Ned lost 14 points
10 4 ( -12 ) + 10 = -48 + 10
= -38
$38 less
11 -3 ( -2 ) + 3 = 6 + 3
= 9
3 ( -4 ) + 9 = -12 + 9
= -3
9 gt -3
-3 ( -2 ) + 3 gt 3 ( -4 ) + 9
12 -8 ( -2 ) -20 = 16 -20
= -4
3 ( -2 ) + 2 = - 6 + 2
= -4
-4 = -4
-8 ( -2 ) -20 = 3 ( -2 ) + 2
13 -7 ( 5 ) - 9 = -35 - 9
= -44
-3 ( 20 ) + 10 = -60 + 10
= -50
-44 gt -50
-7 ( 5 ) -9 gt -3 ( 20 ) + 10
14 -16 ( 0 ) -3 = 0 -3
= -3
-8 ( -2 ) -3 = 16 -3
= 13
-3 lt 13
-16 ( 0 ) -3 lt -8 ( -2 ) -3
15 A negative number usually represents a debt
payment or loss or a change that is a decrease
such as to a savings account
Independent Practice
16 -12 ( -3 ) + 7 = 36 + 7
= 43
17 -42 divide ( -6 ) + 5 -8 = 7 + 5 -8
= 12 -8
= 4
18 10 ( -60 ) -18 = -600 -18
= -618
19 ( -11 ) ( -7 ) + 5 - 82 = 77 + 5 - 82
= 82 - 82
= 0
20 35 divide ( -7 ) + 6 = -5 + 6
= 1
21 -13 ( -2 ) - 16 - 8 = 26 - 16 - 8
= 10 - 8
= 2
22 a 5 ( 2 ) -12 + 3 = 10 -12 + 3
= -2 + 3
= 1
b -3 ( 2 ) -1 + 6 + 7 = -6 -1 + 6 + 7
= -7 + 6 + 7
= -1 + 7
= 6
c Rose has more points than Lily so Rose won
the game
23 5 ( -4 ) -8 = -20 - 8 = -28
24 -36 divide ( -4 ) + 9 = 9 + 9 = 18
Copyright copy by Houghton Mifflin Harcourt 8 All rights reserved
25 a 4 ( -35 ) -9 = -140 -9
= -149
$149 less
b Yes $200 - $149 = $51 $51 gt $50 so Arleen
has enough money
26 a 2 ( -10 ) + 3 = -20 + 3= -17
b 7 + 2 + ( -7 ) = 2
c Warren since 2 is greater than -17
d Sample answer 2 of clubs 2 of spades
3 of spades king of diamonds 10 of clubs
7 of clubs
Focus on Higher Order Thinking
27 Sample answer Ann bought three shirts for $7 each
and a pair of pants for $10 Her mother gave her
$25 By how much did the amount of money Ann
had change
28 Disagree the quotient of two integers is positive if
the integers have the same sign So the first two
integers could have been negative integers
29 5 feet equals 60 inches so Lisa is holding the rock
60 inches above the waterrsquos surface The rock will
travel 4 times -5 = -20 inches or 20 inches below the
surface in 4 seconds 60 + 20 = 80 inches
MODULE 2
Ready to Go On
1 Since the numbers have opposite signs the product
will be negative
( -2 ) ( 3 ) = -6
2 Since the numbers have the same sign the product
will be positive
( -5 ) ( -7 ) = 35
3 Since the numbers have the opposite signs the
product will be negative
( 8 ) ( -11 ) = -88
4 ( -3 ) ( 2 ) ( -2 ) = ( -6 ) ( -2 ) = 12
5 5 ( -3 ) = -15 -15degC
6 -63 ____ 7 = -9
7 -15 ____ -3
= 5
8 0 ____ -15
= 0
9 96 ____ -12
= -8
10 -24 divide 6 = -4 -4 Ib
11 ( -4 ) ( 5 ) + 8 = -20 + 8
= -12
12 ( -3 ) ( -6 ) -7 = 18 -7
= 11
13 -27 ____ 9 - 11 = -3 - 11
= -14
14 -24 ____ -3
- ( -2 ) = 8 + 2
= 10
15 Sample answer Maurice lost 3 nickels in the laundry
and found 1 dime in the couch By how much did the
amount of money he had change
( -3 ) ( 5 ) + 10 = -15 + 10 = -5 He had $05 less
than before
Copyright copy by Houghton Mifflin Harcourt 9 All rights reserved
MODULE 3 Rational Numbers
Are You Ready
1 9 ___ 14
times 7 __ 6 =
3
2
9 ___ 14
times 7 __ 6 1
2
= 3 __ 4
2 3 __ 5 times 4 __
7 = 12 ___
35
3 11 ___ 8
times 10 ___ 33
= 1
4
11 ___ 8 times 10 ___
33 5
3
= 5 ___ 12
4 4 __ 9 times 3 =
3
4 __ 9 times 3 __
1 1
= 4 __ 3 or 1 1 __
3
5 1 __ 2 divide 1 __
4 = 1 __
2 times 4 __
1
=
1 1 __ 2 times 4 __
1 2
= 2 __ 1 = 2
6 3 __ 8 divide 13 ___
16 = 3 __
8 times 16 ___
13
= 1 3 __ 8 times 16 ___
13 2
= 6 ___ 13
7 2 __ 5 divide 14 ___
15 = 2 __
5 times 15 ___
14
= 1
1 2 __ 5 times 15 ___
14 3
7
= 3 __ 7
8 4 __ 9 divide 16 ___
27 = 4 __
9 times 27 ___
16
= 1
1 4 __ 9 times 27 ___
16 3
4
= 3 __ 4
9 3 __ 5 divide 5 __
6 = 3 __
5 times 6 __
5
= 18 ___ 25
10 1 __ 4 divide 23 ___
24 = 1 __
4 times 24 ___
23
= 1 1 __ 4 times 24 ___
23 6
= 6 ___ 23
11 6 divide 3 __ 5 = 6 __
1 times 5 __
3
= 2
6 __ 1 times 5 __
3 1
= 10 ___ 1 = 10
12 4 __ 5 divide 10 = 4 __
5 times 1 ___
10
= 2
4 __ 5 times 1 ___
10 5
= 2 ___ 25
13 21 - 6 divide 3
21 - 2
19
14 18 + ( 7 - 4 ) times 3
18 + 3 times 3
18 + 9
27
15 5 + ( 8 - 3 ) 2
5 + ( 5 ) 2
5 + 25
30
16 9 + 18 divide 3 + 10
9 + 6 + 10
15 + 10
25
17 60 - ( 3 - 1 ) 4 times 3
60 - ( 2 ) 4 times 3
60 - 16 times 3
60 - 48
12
18 10 - 16 divide 4 times 2 + 6
10 - 4 times 2 + 6
10 - 8 + 6
2 + 6
8
LESSON 31
Your Turn
0 _
571428
4 7 ⟌ _
40000000 Dividing into 40
_ -35
50
_ -49
10
_ -7
30
_ -28
20
_ -14
60
_ -56
40 Second appearance of 40
Because the number 40 repeats during the division
process the answer is a repeating decimal
-0 _
571428 or -0571428571428hellip
Copyright copy by Houghton Mifflin Harcourt 10 All rights reserved
0 _ 3
5 3 ⟌ _
100 Dividing into 10
_ -3
10 Second appearance of 10
Because the number 10 repeats during the division
process the answer is a repeating decimal 0 _ 3 or
0333hellip
045
6 20 ⟌ _
900
_ -8 0
1 00
_ -1 00
0
-045
7 -2 3 __ 4 = -thinsp 4 times 2 + 3
_________ 4 = -11 ____
4
275
4 ⟌ _
1100
_ -8
30
_ -28
20
_ -20
0
-275 terminating
8 7 1 __ 3 =
3 times 7 + 1 _________
3 = 22 ___
3
7 _ 3
3 ⟌ _
2200 Dividing into 10
_ -21
1 0 Second appearance of 10
Because the number 10 repeats during the division
process the answer is a repeating decimal 7 _ 3 or
7333hellip repeating
Guided Practice
06
1 5 ⟌ _
30
_ -3 0
0
06 terminating
089
2 100 ⟌ _
8900
_ -80 0
9 00
_ -9 00
0
-089 terminating
3 Simplify the fraction
4 ___ 12
= 4 times 1 _____ 4 times 3
= 1 __ 3
0 _ 3
3 ⟌ _
100 Dividing into 10
_ -3
10 Second appearance of 10
Because the number 10 repeats during the division
process the answer is a repeating decimal 0 _ 3 or
0333hellip repeating
0 _
25
4 99 ⟌ _
25000 Dividing into 25
_ -19 8
520
_ -495
25 Second appearance of 25
Because the number 25 repeats during the division
process the answer is a repeating decimal 0 _
25 or
02525hellip repeating
0 _ 7
5 9 ⟌ _
700 Dividing into 70
_ -63
70 Second appearance of 70
Because the number 70 repeats during the division
process the answer is a repeating decimal 0 _ 7 or
-0777hellip repeating
036
6 25 ⟌ _
900
_ -7 5
1 50
_ -1 50
0
-036 terminating
004
7 25 ⟌ _
100
_ -1 00
0
004 terminating
01420 _
45
8 176 ⟌ _
250000000
_ -17 6
7 40
_ -7 04
360
_ -352
80
_ -0
800 First appearance of 800
_ -704
960
_ -880
800 Second appearance of 800
Because the number 800 repeats during the
division process the answer is a repeating decimal
-01420 _
45 or -014204545hellip repeating
0012
9 1000 ⟌ _
12000
_ -10 00
2 000
_ -2 000
0
0012 terminating
Copyright copy by Houghton Mifflin Harcourt 11 All rights reserved
10 -11 1 __ 6 = -thinsp 6 times 11 + 1
_________ 6 = -67 ____
6
111 _ 6
6 ⟌ _
67000
_ -6
07
_ -6
1 0
_ -6
40 First appearance of 40
_ -36
40 Second appearance of 40
Because the number 40 repeats during the division
process the answer is a repeating decimal
- 67 ___ 6
-111 _ 6 or -111666hellip
11 2 9 ___ 10
= 10 times 2 + 9
__________ 10
= 29 ___ 10
29
10 ⟌ _
290
_ -20
9 0
_ -9 0
0
29 ___ 10
29
12 -8 23 ____ 100
= - 100 times 8 + 23
____________ 100
= -823 _____ 100
823
100 ⟌ _
82300
_ -800
23 0
_ -20 0
3 00
_ -3 00
0
-823 _____ 100
-823
13 7 3 ___ 15
= 15 times 7 + 3
__________ 15
= 108 ____ 15
72
15 ⟌ _
1080
_ -105
3 0
_ -3 0
0
108 ____ 15
72
14 54 3 ___ 11
= 11 times 54 + 3
__________ 11
= 597 ____ 11
54 _
27
11 ⟌ _
597000
_ -55
47
_ -44
30 First appearance of 30
_ -22
80
_ -77
30 Second appearance of 30
Because the number 30 repeats during the division
process the answer is a repeating decimal
597 ____ 11
54 _
27 or 542727hellip
15 -3 1 ___ 18
= -thinsp 18 times 3 + 1 __________
18 = -55 ____
18
30 _ 5
18 ⟌ _
55000
_ -54
1 0
_ -0
1 00 First appearance of 100
_ -90
100 Second appearance of 100
Because the number 100 repeats during the division
process the answer is a repeating decimal
-55 ____ 18
-30 _ 5 or -30555hellip
16 3 2 __ 3 =
3 times 3 + 2 _________
3 = 11 ___
3
3 _ 6
3 ⟌ _
1100
_ -9
2 0 First appearance of 20
_ -1 8
20 Second appearance of 20
Because the number 20 repeats during the division
process the answer is a repeating decimal
3 _ 6 or 3666hellip lbs of apples
17 -2 7 __ 8 = -
8 times 2 + 7 _________
8 = -23 ____
8
2875
8 ⟌ _
23000
_ -16
7 0
_ -6 4
60
_ -56
40
_ -40
0
-2875 lb
18 Disagree the definition of a rational number is a
number that can be written as the ratio of two
integers with a denominator not equal to zero and
3 ___ 47
is a well-defined ratio of two integers Tom did
not divide long enough to correctly determine that
the quotient is a repeating decimal
Copyright copy by Houghton Mifflin Harcourt 12 All rights reserved
Independent Practice
19 basketball players
_______________ football players
= 5 ___ 11
0 _
45
11 ⟌ _
5000 Dividing into 50
_ -4 4
60
_ -55
50 Second appearance of 50
Because the number 50 repeats during the division
process the answer is a repeating decimal
5 ___ 11
0 _
45 or 04545hellip repeating
20 hockey players
______________ lacrosse players
= 6 ___ 10
06
10 ⟌ _
60
_ -6 0
0
6 ___ 10
06 terminating
21 polo players
_____________ football players
= 4 ___ 11
036
11 ⟌ _
4000 Dividing into 40
_ -3 3
70
_ -66
40 Second appearance of 40
Because the number 40 repeats during the division
process the answer is a repeating decimal
4 ___ 11
0 _
36 or 03636hellip repeating
22 lacrosse players
______________ rugby players
= 10 ___ 15
= 5 times 2 _____ 5 times 3
= 2 __ 3
0 _ 6
3 ⟌ _
200 Dividing into 20
_ -1 8
20 Second appearances of 20
Because the number 20 repeats during the division
process the answer is a repeating decimal
10 ___ 15
0 _ 6 or 0666hellip repeating
23 football players
_____________ soccer players
= 11 ___ 11
= 1
11 ___ 11
1 terminating
24 Agree Sample answer There are 10 players on the
lacrosse team and dividing the number of any other
team by 10 will simply move the decimal point one
digit to the left Therefore the ratio of any team over
the lacrosse team will be a decimal that terminates
one place to the right of the decimal point
25 a -4 7 __ 8 = -thinsp 8 times 4 + 7
_________ 8 = - 39 ___
8
b 4875
8 ⟌ _
39000
_ -32
7 0
_ -6 4
60
_ -56
40
_ -40
0
-4875
c Sample answer 4 7 __ 8 is very close to 5 Therefore
You could estimate that the water level changes
by 5 inches per month The total change in the
water level at the end of the 3-month period
would be approximately -15 inches
26 integer terminating
27 Ben is taller because Benrsquos height of 5 5 ___ 16
is equal
to 85 ___ 16
or 53125 ft while Marcusrsquo height of 5 7 ___ 24
is
equal to 127 ____ 24
or 52916hellip ft
28 The first store has the better deal because they
offer 3 __ 4 or 075 of a bushel for $9 while the second
store offers only 2 __ 3 or 0666hellip of a bushel for $9
Focus on Higher Order Thinking
29 When the number 1 is the denominator in a fraction
its decimal form is simply the numerator In all other
cases concerning numbers 1 to 10 the division
process stops when either the remainder is 0 or
when the digits begin to repeat When the numbers
2 4 5 or 8 are in the denominator the decimal form
of a fraction will terminate When the numbers
3 6 7 or 9 are in the denominator the decimal form
of a fraction will be a repeating decimal
30 Julie made a higher score on her math test since
her math test score of 21 ___ 23
is equal to a repeating
decimal of approximately 0913 while her science
test score of 29 ___ 32
is equal to a terminating decimal of
090625
Sample answer The difference in scores cannot be
determined by simply comparing the numerators of
the two fractions because the denominators are not
the same For Julie to compare her scores she
needs to divide the denominators into their respec-
tive numerators until one of the quotients is found to
be greater than the other
31 No although the digits in the decimal appear to
follow a pattern a repeating decimal must have the
same combination of digits that repeat such as
0121212hellip
Copyright copy by Houghton Mifflin Harcourt 13 All rights reserved
LESSON 32
Your Turn
2
50 1 2 3 4
3 + 1 1 __ 2 = 4 1 __
2
3
0-7 -6 -5 -4 -3 -2 -1
-25 + ( -45 ) = -7
6
0 1 2-5-6-7-8 -4 -3-2-1
-8 + 5 = -3
7
10-1
1 __ 2 + ( - 3 __
4 ) = - 1 __
4
8
3 4 5 6 7 80 1 2-3-2-1
-1 + 7 = 6
9
3 4 50 1 2-5-4 -3-2-1
2 1 __ 2 + ( -2 1 __
2 ) = 0
10
3 4 50 1 2-5-4 -3-2-1
-45 + 45 = 0
11
1-1 0
3 __ 4 + ( - 3 __
4 ) = 0
The overall change is 0 cups
12 -15 + 35 + 2
-15 + 55
55 - 15
4
13 3 1 __ 4 + ( -2 ) + ( -2 1 __
4 )
3 1 __ 4 + ( -4 1 __
4 )
3 1 __ 4 - 4 1 __
4
-1
14 -275 + ( 325 ) + 5
-6 + 5
-1
15 15 + 8 + ( -3 )
23 + 3
20
Guided Practice
1
3 4 50 1 2-5-4 -3-2-1
-3 + ( -15 ) = -45
2
0 54321-5-4-3-2-1
15 + 35 = 5
3
0 105-1 -05
1 __ 4 + 1 __
2 = 3 __
4
4
0 54321-5-4-3-2-1
-1 1 __ 2 + ( -1 1 __
2 ) = -3
5
0 54321-5-4-3-2-1
3 + ( -5 ) = -2
6
0 54321-5-4-3-2-1
-15 + 4 = 25
7 -2150 + 2150 = 0 $0
8 -874 + 874 = 0 $0
9 275 + ( -2 ) + ( -525 )
275 + ( -725 )
- ( 725 - 275 )
-45
10 -3 + 1 1 __ 2 + 2 1 __
2 = -3 + 4 = 1
11 124 + 92 + 1
-124 + 102
- ( 124 - 102 )
-22
12 -12 + 8 +13
-12 + 21
21 - 12
9
13 45 + ( -12 ) + ( -45 )
45 + ( -45 ) + ( -12 )
0 + ( -12 )
-12
14 1 __ 4 + ( - 3 __
4 ) = - ( 3 __
4 - 1 __
4 ) = - 2 __
4 = - 1 __
2
Copyright copy by Houghton Mifflin Harcourt 14 All rights reserved
15 -4 1 __ 2 + 2 = - ( 4 1 __
2 - 2 ) = -2 1 __
2
16 -8 + ( -1 1 __ 8 ) = -9 1 __
8
17 Start at -4 and move 6 units to the right
The sum is 2
Independent Practice
18 The opposite of +19 is -19
19 -$225 + $1500 = $1500 - $225 = $1275
20 -3525 m + ( -85 ) = -4375 m
21 4 3 __ 4 mi + ( -3 1 __
4 mi ) = 1 2 __
4 mi = 1 1 __
2 mi
22 1635 m + ( -05 m ) = 163 m above sea level
23 30 + 15 - 25 = 45 - 25 = 20 pts
24 January
Income - Expenses
$1205 - $129060
- ( $129060 - $1205 ) -$8560
February
Income - Expenses
$1183 - $134544
-($134544 - $1183)
-$16244
Kameh lost $8560 in January and $16244 in
February
25 June
Income - Expenses
$2413 - $210623
$30677
July
Income - Expenses
$2260 - $195850
$30150
August
Income - Expenses
$2183 - $184512
$33788
Kameh gained $30677 in June $30150 in July and
$33788 in August
26 First sum all the values in the Income column Then
sum all the values in the Expenses column Subtract
the total expenses from the total income Finally add
the $250 profit from December (not shown in the
table) to find the total profit or loss of the bakery by
the end of August
Income = $1205 + $1183 + $1664 + $2413
$2260 + $2183 = $10908
Expenses = $129060 + $134544 + $1664 +$210623 + $195850 + $184512
= $1020989
Profit = $10908 - $1020989 + $250
= $94811
27 -2 is the opposite or additive inverse of 2
28 a 7 ( 10 ) + 3 ( -15 ) = 70 - 45 = 25 pts
b 2 ( 10 ) + 8 ( -15 ) = 20 - 120 = -100 pts
c 10 + 10 + 10 + 10 + 10 + ( ndash15 ) + ( ndash15 ) + ( ndash15 ) +
( ndash15 ) + ( ndash15 ) or 5 ( 10 ) + 5 ( ndash15 )
Focus on Higher Order Thinking
29 The sum of two negative rational numbers is always
negative The sum of a negative rational number and
a positive rational number is negative if the absolute
value of the negative number is greater than that of
the positive number
30 Sample answer The student might have subtracted
the absolute values of the numbers
31 Yes 55 and -55 are opposites and -23 and 23
are opposites so the expression [ 55 + ( -23 ) ] +
( -55 + 23 ) can be viewed as the sum of two
opposites which is always 0
LESSON 33
Your Turn
1
-9 -8 -7 -6 -5 -4
-65 - 2 = -85
2
42 30-1 1
1 1 __ 2 - 2 = - 1 __
2
3
-10-9 -8 -7 -6 -5 -4 -3 -2 -1 0
-225 - 55 = -775
6
1 2-1 0
025 - ( -150 ) = 175
7
1-1 0
- 1 __ 2 - ( - 3 __
4 ) = 1 __
4
Guided Practice
1
1312111098765 14 15
5 - ( -8 ) = 13
2
-9 -8 -7 -6 -5 -4 -3
3 1 __ 2 - 4 1 __
2 = -8
Copyright copy by Houghton Mifflin Harcourt 15 All rights reserved
3
-15 -13 -11 -9 -5-7
-7 - 4 = -11
4
-6 -5 -4 -3 -2 -1 0 1
-05 - 35 = -4
5 -14 - 22 = -36
6 -125 - ( -48 )
-125 + 48
- ( 125 - 48 )
-77
7 1 __ 3 - ( - 2 __
3 ) = 1 __
3 + 2 __
3 = 1
8 65 - ( -14 ) = 65 + 14 = 79
9 - 2 __ 9
- ( -3 )
- 2 __ 9
+ 3
3 - 2 __ 9
2 9 __ 9 - 2 __
9
2 7 __ 9
10 24 3 __ 8
- ( -54 1 __ 8 )
24 3 __ 8
+ 54 1 __ 8
78 4 __ 8
78 1 __ 2
11 -1 m + ( 105 m ) = -15 m
15 m below sea level
12 -12 1 __ 2 + ( -5 ) = -17 1 __
2
17 1 __ 2
or 175 yards
13 Change in height = Starting height - ending height
533 ft - ( -10 ft ) = 533 ft + 10 ft = 543 ft
14 -4500 + (-3015) = -7515 $7515
15 Explain that she is supposed to start at positive 4 on
the number line then move 12 places to the left
because she is subtracting a positive number She
will end on the number -8 which is the answer
Independent Practice
16 -126degC - 75degC = -201degC
17 -2565 ft - 165 ft + 1245 ft = -297 ft
The diver is 297 ft below the surface
18 -9500 ft - ( -26000 ft ) = 16500 ft
19 29035 ft - ( -36198 ft ) = 65233 ft
70000 ft - ( -26000 ft ) = 96000 ft
Mars has the greater difference by
96000 ft - ( 65233 ft ) = 30767 ft
20 a -5degF + 78degF - 32degF
b 78degF - 32degF
c -5degF + 78degF - 32degF 78degF - 5degF - 32degF 78degF - 37degF = 41degF 78degF - 32degF = 46degF
21 a -$1258 + ( -$3072 ) = -$4330
b -$4330 + ( -$25 ) = -$6830
c $6830 since -$6830 + $6830 = 0
22 a No 4 times 52 in = 208 in
b 208 in - 20 in = 08 in more needed
23 a 5 ft - 72 ft + 22 ft
b 5 ft - 72 ft + 22 ft
5 ft + 22 ft - 72 ft
72 ft - 72 ft
= 0 ft because he moved the same distance
backward and forward
24 a Yes
$425 + $089 + $1099
= $1613 lt $20
b $20 - $1613 = $387 left over
Focus on Higher Order Thinking
25 The Commutative Property of Addition (CPA) could
be used to simplify the two terms that already have
a common denominator first
- 7 ___ 16
- 1 __ 4 - 5 ___
16 = ( - 7 ___
16 ) + ( - 1 __
4 ) + ( - 5 ___
16 )
( - 7 ___ 16
) + ( - 5 ___ 16
) + ( - 1 __ 4 ) by CPA
( -7 + ( -5 ) __________
16 ) + ( - 1 __
4 )
( -12 ____ 16
) + ( - 1 __ 4 )
( - 4 times 3 _____ 4 times 4
) + ( - 1 __ 4 )
( - 3 __ 4 ) + ( - 1 __
4 )
( -3 + ( -1 ) __________
4 )
( -4 ___ 4 ) = -1
26 Lowest -225degF + ( -12degF ) = -345degFHighest -195degF + ( -12degF ) = -315degF
27 Sample answer Yes because both numbers are
rational numbers each can be written as the ratio of
two integers for example a __ b
and c __ d
Both fractions
could be given a common denominator and then
one could then be subtracted from the other The
result would be a fraction which is a rational number
28 No Sample answer It is possible for the
difference of two negative numbers to be negative
[ -4 - ( -1 ) = -3 ] but it is also possible for the
difference to be positive [ -5 - ( -8 ) = 3 ]
Copyright copy by Houghton Mifflin Harcourt 16 All rights reserved
LESSON 34
Your Turn
1
-8 -7 -6 -5 -2 -1 0-4 -3
2 ( -35 ) = -7
2
-2 -1 0 1 2 3 4-4 -3
-3 ( -125 ) = 375
4 ( - 3 __ 4 ) ( - 4 __
7 ) ( - 2 __
3 ) = -
13 times 41 times 2 __________ 14 times 7 times 31
= - 1 times 1 times 2 _________ 1 times 7 times 1
= - 2 __ 7
5 ( - 2 __ 3 ) ( - 3 __
4 ) ( 4 __
5 ) = 2 times 31 times 41
__________ 13 times 41 times 5
= 2 times 1 times 1 _________ 1 times 1 times 5
= 2 __ 5
6 ( 2 __ 3 ) ( - 9 ___
10 ) ( 5 __
6 ) = -
12 times 93 times 51
____________ 13 times 210 times 63
= - 1 times 31 times 1 __________ 1 times 2 times 31
= - 1 __ 2
Guided Practice
1
-5 -2 -1 0-4 -3
5 ( - 2 __ 3 ) = 5 __
1 times ( - 2 __
3 )
= - 5 times 2 _____ 1 times 3
= - 10 ___ 3
= -3 1 __ 3
2
-1 -05 0-2 -15
3 ( - 1 __ 4 ) = 3 __
1 times - 1 __
4
= - 3 times 1 _____ 1 times 4
= - 3 __ 4
3
0 1 2-2 -1
-3 ( - 4 __ 7 ) = 3 __
1 times 4 __
7
= 3 times 4 _____ 1 times 7
= 12 ___ 7
= 1 5 __ 7
4
-2 -1 0 1 2 3 4-4 -3
- 3 __ 4 ( -4 ) = 3 __
4 times 4 __
1
= 3 times 41
______ 14 times 1
= 3 times 1 _____ 1 times 1
= 3 __ 1
= 3
5 4 ( -3 ) = -12
6 -18 ( 5 ) = -9
7 -2 ( -34 ) = 68
8 054 ( 8 ) = 432
9 -5 ( -12 ) = 6
10 -24 ( 3 ) = -72
11 1 __ 2 times 2 __
3 times 3 __
4 = ( 1 times 21
______ 12 times 3
) ( 3 __ 4 )
= ( 1 __ 3 ) ( 3 __
4 )
= 1
1 __ 3 times 3 __
4 1
= 1 __ 4
12 - 4 __ 7 ( -thinsp 3 __
5 ) ( - 7 __
3 ) = ( - 4 times 3 _____
7 times 5 ) ( - 7 __
3 )
= 12 ___ 35
( - 7 __ 3 )
= - 4
5 12 times 7 ______ 35 times 3
1
1
= - 4 times 1 _____ 5 times 1
= - 4 __ 5
13 ( - 1 __ 8 ) times 5 times 2 __
3 = ( - 1 __
8 ) times 5 __
1 times 2 __
3
= - 1 times 5 times 21
__________ 48 times 1 times 3
= - 1 times 5 times 1 _________ 4 times 1 times 3
= - 5 ___ 12
Copyright copy by Houghton Mifflin Harcourt 17 All rights reserved
14 ( - 2 __ 3
) ( 1 __ 2 ) ( - 6 __
7 ) = 2 times 1 times 62
__________ 13 times 21 times 7
= 1 times 1 times 2 _________ 1 times 1 times 7
= 2 __ 7
15 4 ( -350 ) = -14 or a $14 change in price
16 18 ( -100 ) = -1800 or a $1800 change
17 Sample answer Count the number of times there is
a negative sign If there are an even number of
negative signs then the final product will be positive
If there is an odd number of negative signs then the
final product will be negative
Independent Practice
18 a 6 ( -1998 ) Note that the change in her bank
account balance does not depend on the initial
amount
b 200 + 6 ( -1998 )
= 200 - 11988
= 8012 $8012
19 Sample answer Start at 0 then move 15 units to
the left (because 15 is negative in this case) 4 times
You are now on -6 Then because 4 is negative in
this case we want to move to the opposite of -6
which is 6
20 8 ( -3 1 __ 4 ) = -8 ( 13 ___
4 )
= - 1
8 __ 1 times 13 ___
4 1
= - 2 times 13 ______ 1 times 1
= - 26 ___ 1
-26 min At the same rate the watch will be
26 minutes behind after 8 weeks
21 3 ( -325 ) = -975 ft The change in depth is -975 ft
Therefore the submarine will be 975 below sea level
(below the surface)
22 5 + ( -3 ) ( 15 )
= 5 + ( -45 )
= 05 cups left
23 Matthew is incorrect Sample answer Matthew
should have said that multiplying by two negatives
is like multiplying the opposite of a positive twice
The opposite of a positive twice brings you back to
a positive
24 5 ( -15 ) = -75 min Therefore she will be late by
75 minutes or 1 hour and 15 minutes
25 Total score is
2 times ( 6 ) + 16 times ( 05 )
+ 7 times ( -05 ) + 2 times ( -15 )
= 12 + 8 - 35 - 3
= 20 - 65
= 135 pts
Focus on Higher Order Thinking
26 Temperature at 5 kilometers
= Temp at ground level + change in temp
= 12 + 5 ( -68 )
= 12 + ( -34 )
= -22degC
27 a b c d
+ + + +
+ + - +
+ - + +
- + + +
- - - +
- - + -
- + - -
+ - - -
28 If the product of two numbers is positive then the two
numbers must have the same sign either they are
both positive or both negative If the sum is negative
then at least one of the numbers must be negative
Therefore the two integers that add to -7 and multiply
to 12 must both be negative The negative paired
factors of 12 are -1 and -12 -2 and -6 and -3
and -4 Of those choices only -3 and -4 add to -7
LESSON 35
Your Turn
3 28 ___ -4
= - 28 ___ 4 = -07
4 -664 ______ -04
= 664 ____ 04
= 166
5 - 55 ___ 05
= - 55 ___ 5 = -11
6 -4256 _______ 112
= -38
The divers change in elevation was -38 feet
per minute
7 - 5 __
8 ___
- 6 __ 7 = - 5 __
8 divide - 6 __
7
= - 5 __ 8 times - 7 __
6
= 35 ___ 48
8 - 5 ___
12 ____
2 __ 3 = - 5 ___
12 divide 2 __
3
= - 5 ___ 12
times 3 __ 2
= - 15 ___ 24
= - 5 __ 8
Copyright copy by Houghton Mifflin Harcourt 18 All rights reserved
9 -4__5
___1__2 =-4__5divide1__
2
=-4__5times2__1
=-8__5
=-13__5
Guided Practice
1 072_____-09=-72___
9 =-08
2 -1__5
___7__5 =-1__
15times5
1__
7=-1times1_____
1times7=-1__7
3 56___-7=-56___7=-8
4 251____4 divide(-3__
8)=251____
4 times-8__
3
=-251times82________
14times3
=-251times2_______1times3
=-502____3
5 75____-1__5
=-75___1times5__
1=-75times5______
1times1=-375
6 -91____-13=91___
13=7
7 -3__7
___9__4 =-
13__7times4__93
=-1times4_____7times3
=-4___21
8 - 12____003
=-1200_____
3 =-400
9 =changeinwaterlevel_________________
changeindays
=-35L______4day
=-0875 L____day
or-0875Lperday
10 =totalchangeinprice_________________
changeindays
=-$4575________5day
=-$915perdayonaverage
11 totalchangeinaltitude___________________
numberofminutes
=-044mi________08min
=-44mi______8min
=-055mileperminute
12 FirstfindthesignofthenumeratorwhichisnegativeNextfindthesignofthedenominatorwhichisnegativeThereforethequotientwillbepositivebecausethenumeratoranddenominatorbothhavethesamesign
Independent Practice
13 5___-2__
8=-5__
1times8__
24
1=-5times4_____
1times1=-20
14 51__3divide(-11__
2)
=-3times5+1_________3 divide2times1+1_________
2
=-16___3divide3__
2
=-16___3times2__
3
=-16times2______3times3
=-32___9
15 -120_____-6 =120____
6 =20
16 -4__5
___-2__
3=
24__5times3__
21=2times3_____
5times1=6__
5
17 103divide(-103)=-103____1 times 1____
103
=-103times1________1times103
=-103____103
=-103____103
=-01
18 -04_____80
=-04___80
=-0005
19 1divide9__5=1__
1times5__
9=5__
9
20 -1___4 ___
23___24
=-1__
14times246
___23
=-1times6______1times23
=-6___23
21 -1035_______-23 =1035_____
23 =45
22 totalhours_____________numberofdays
= 21h______7days
=3 h____day
totaltimelost3 h____day
times3days=9hours
Alexusuallyruns21hoursperweeksodivideby7tofindthatheruns3hoursperdaySinceheisunabletorunfor3dayshistimeisdecreasedby9hoursor-9
23 totalchangeinyards
_________________numberofruns
=-4times15+3___________4 times1__
9
yd___run
=-763___4 times1__
91yd
___run
=-153__
4yd______
9runs
=-153__4times1__
9
yd___run
=-7__4or-13__
4yardsperrun
CopyrightcopybyHoughtonMifflinHarcourt 19 Allrightsreserved
DO NOT EDIT--Changes must be made through File info CorrectionKey=B
7_MCABESK207233_U1M03indd 19 103113 759 PM
24 -121degC + ( -78degC ) + ( -143degC ) + ( -72degC )
_____________________________________ 4
= 414degC ______ 4
= -1035degC per day
25 a total profit
_____________ number of days
= $1750
______ 7 days
= $250 per day
b $150
_____ day
times 7 days = $1050
c total change
_____________ number of days
= - $490
______ 7 days
= -$70 per day
26 total meters descended ___________________ number of seconds
= 996 m ______ 12 s
= 83 ms
27 When converting the division equation into a
multiplication problem he forgot to multiply by the
reciprocal and instead multiplied by the fraction in
the denominator The correct answer is given by
- 3 __
4 ___
4 __ 3
= - 3 __
4 times 3 __
4 = - 9 ___
16
28 -37 m _______ year times ( 2012 ndash 1995 ) years
= -37 m _______ year times 17 years
= -629 m
Focus on Higher Order Thinking
29 Sample answer The average change in temperature
per day would be given by -85 divide 15 if the
temperature were to drop of 85degF over 15 days
-85degF divide 15 d
= - 1785 ____ 315
degF __ d
= - 17 ___ 3 degF __
d or -5 2 __
3 degF __
d asymp -567 degF __
d
On average the temperature changed by -567degF
every day
30 Yes By definition the result of dividing an integer by
a non-zero integer is a rational number
31 Yes The result of dividing an integer by a non-zero
integer always results in a rational number by
definition
LESSON 36
Your Turn
1 Find the total commercial time
3 times 2 1 __ 2 = 7 1 __
2
Find the total entertainment time
30 - 7 1 __ 2 = 22 1 __
2
Find the length of each entertainment segment
22 1 __ 2 divide 4 = 5 5 __
8
Each entertainment segment is 5 5 __ 8 minutes long
2 Find the number of cups of sugar in the bag
454 divide 48 asymp 95
Find the number of 3 __ 4 -cup portions in the bag
95 divide 075 asymp 127
12 batches can be made from the bag of sugar
Find the cost of 1 batch
349 divide 12 asymp 029
The cost of the sugar is $029 per batch
3 Convert the percent to a decimal
12 3 __ 5 = 126
= 0126
Find the worth after 1 year
750 times 0126 = 945
750 + 945 = 8445
Find the worth after 2 years
8445 times 0126 asymp 10641
8445 + 10641 = 95091
Find the worth after 3 years
95091 times 0126 asymp 11981
95091 + 11981 = 107072
The stock is worth $107072
Guided Practice
1 45h times 3 1 __ 5 or 32 miles per hour = 144 miles
144 miles divide 3 3 __ 5 or 36 miles per hour = 4 hours
2 2568 inches times -002375 asymp -061 inches
2568 inches - 061 asymp 2507 inches
3 Sample answer Using a calculator to solve a
problem that involves complicated arithmetic can
help you avoid errors It can also help you to check
solutions to any problems you solved by hand
Independent Practice
4 Find the total weight
78 times 3 = 234
Find the weight each climber carries
234 divide 4 = 585
Each climber carries 585 kg
Copyright copy by Houghton Mifflin Harcourt 20 All rights reserved
5 Find the available width on the page
12 - 3 1 __ 2 = 8 1 __
2
Find half the width
8 1 __ 2 divide 2 = 4 1 __
4
He should put the picture 4 1 __ 4 inches from each side
of the page
6 Find the amount of cereal needed for all the children
11 times 1 __ 3 = 3 2 __
3
10 times 3 __ 4 = 7 1 __
2
3 2 __ 3 + 7 1 __
2 = 11 1 __
6
Compare the total needed with the amount in the
box
11 1 __ 6 lt 12
Yes there is enough Oaties for all the children The
amount needed is 11 1 __ 6 cups and that is less than the
amount in the box 12 cups
7 Find half of the distance that the referee walked
41 3 __ 4 divide 2 = 20 7 __
8
Find how far that distance is from the goal line
50 - 20 7 __ 8 = 29 1 __
8
The referee is 29 1 __ 8 feet from the nearest goal line
8 Donovanrsquos score was 39 ___ 50
= 78 Marcirsquos score was
( 78 + 10 ) = 88
9 Find the number Marci answered correctly
88 = 88 ____ 100
= 44 ___ 50
Find how many more that Marci answered than
Donovan
44 - 39 = 5
Marcie answered 5 more questions correctly than
Donovan
10 Sample answer Donovan got about 40 out of 50
questions right or about 80 Since Marci scored
10 more that is about 90 90 times 50 is 45 So
Marci answered about 45 - 40 or 5 more questions
correctly than Donovan
11 Yes -075 is a reasonable estimate
19 ___ 37
is about 1 __ 2 and 143 is about 15 and
15 times ( - 1 __ 2 ) = -075
12 Sample answer approximately -07343 Use a
calculator Divide -19 by 37 multiply the quotient by
143 then round the product
13 Sample answer Yes -07343 asymp - 075
Focus on Higher Order Thinking
14 Find the time of the descent
-79 9 ___ 10
divide ( -188 ) = 425
Find the time for the ascent
19 1 __ 8 - 1275 - 425 = 2 1 __
8
Find the distance of the ascent
-28 9 ___ 10
- ( -79 9 ___ 10
) = 51
Find the rate of the ascent
51 divide 2 1 __ 8 = 24
The diverrsquos rate of change in elevation during the
ascent was 24 ftmin
15 Sample answer
(1) Convert the mixed number 27 3 __ 5 to the decimal
276 find the sum of 276 and 159 then multiply
the result by 037
(2) Convert the mixed number 27 3 __ 5 to the decimal
276 Then use the Distributive Property so that
(276 + 159)037 = (276)(037) + (159)(037)
Multiply both 276 and 159 by 037 and add the
products I would use the first method because
there are fewer steps and so fewer chances to
make errors
16 Sample answer You need to know how many
gallons of paint you need to paint a wall Measure
the length and width of the wall with a yardstick
then find the area Use the calculator to divide the
area by the number of square feet a gallon of the
paint covers Round up rather than down to the
nearest gallon so you have enough paint
MODULE 3
Ready to Go On
1 4 1 __ 5 =
5 times 4 + 1 _________
5 = 21 ___
5
42
5 ⟌ _
210
_ -20
1 0
_ -1 0
0
42
Copyright copy by Houghton Mifflin Harcourt 21 All rights reserved
2 12 14 ___ 15
= 15 times 12 + 14
___________ 15
= 194 ____ 15
129 _ 3
15 ⟌ _
194000
_ -15
44
_ -30
14 0
_ -13 5
50 first 50
_ -45
50 second 50
Because the number 50 repeats during the division
process the answer is a repeating decimal
129 _ 3 or 12933
3 5 5 ___ 32
= 32 times 5 + 5
__________ 32
= 165 ____ 32
515625
32 ⟌ _
16500000
_ -160
5 0
_ -3 2
1 80
_ -1 60
200
_ -192
80
_ -64
160
_ -160
0
515625
4 45 + 71 = 116
5 5 1 __ 6 + ( -3 5 __
6 ) = 4
6+1 ____
6 -3 5 __
6
= 1 2 __ 6
= 1 1 __ 3
6 - 1 __ 8 -6 7 __
8 = - 1 __
8 + ( -6 7 __
8 )
= -6 8 __ 8
= -7
7 142 - ( -49 ) = 142 + 49
= 191
8 -4 ( 7 ___ 10
) = - 4 __ 1 times 7 ___
10
= - 24 times 7 _______ 1 times 105
= - 2 times 7 _____ 1 times 5
= - 14 ___ 5 or -2 4 __
5
9 -32 ( -56 ) ( 4 ) = 32 times 56 times 4
= 7168
10 - 19 ___ 2 divide 38 ___
7 = -
119 times 7 _______ 2 times 382
= - 1 times 7 _____ 2 times 2
= - 7 __ 4
11 -3201 _______ -33
= 3201 _____ 33
97
33 ⟌ _
3201
_ -297
23 1
_ -23 1
0
97
12 Add the initial stock price with the increase from the
second day
$8360 + $1535 = $9895
Convert the percent decrease to a decimal
-4 3 __ 4 = -475 or -00475
Multiply the price on the second day times the
percent decrease and then subtract the result from
the price on the second day to find the final stock
price
$9895 times -00475 asymp -$47
$9895 - $47 = $9425
The final stock price is $9425 Yes this is
reasonable price on day 1 asymp $85 price on day
2 asymp $100 So the price on day 3 asymp $95
13 Sample answer You can use negative numbers to
represent temperatures below zero or decreases in
prices
Copyright copy by Houghton Mifflin Harcourt 22 All rights reserved
MODULE 4 Ratios and Proportionality
Are You Ready
1 3 __ 4 divide 4 __
5 = 3 __
4 times 5 __
4
= 15 ___ 16
2 5 __ 9 divide 10 ___
11 = 5 __
9 times 11 ___
10
= 1
5 __ 9 times 11 ___
10 2
= 11 ___ 18
3 3 __ 8 divide 1 __
2 = 3 __
8 times 2 __
1
= 4
3 __ 8 times 2 __
1 1
= 3 __ 4
4 16 ___ 21
divide 8 __ 9 = 16 ___
21 times 9 __
8
=thinsp 2
7 16 ___ 21
times 9 __ 8 3
1
= 6 __ 7
5 B ( -4 1 )
6 C ( 3 0 )
7 D ( 5 4 )
8 E ( -2 -2 )
9 F ( 0 0 )
10 G ( 0 -4 )
LESSON 41
Your Turn
3 1 __ 6 acre divide ( 1 __
4 hour ) = 1 __
6 times 4 __
1
= 3
1 times 4 _____ 6 times 1
2
= 1 times 2 _____ 3 times 1
= 2 __ 3 acre per hour
4 3 cups divide ( 3 __ 4 cups ) = 3 __
1 divide 3 __
4
= 3 __ 1 times 4 __
3
= 1
3 times 4 _____ 1 times 3
1
= 1 times 4 _____ 1 times 1
= 4 cups
5 Jaylan 3 __ 4 divide 1 __
5 = 3 __
4 times 5 __
1 = 15 ___
4 = 3 3 __
4
Wanchen 2 __ 3 divide 1 __
6 = 2 ___
1 3 times 6
2 __
1 = 4 __
1 = 4
Jaylanrsquos unit rate is 3 3 __ 4 cups of water per cup of lime
juice Wanchenrsquos unit rate is 4 cups of water per cup
of lime juice Wanchenrsquos limeade has a weaker lime
flavor because 4 gt 3 3 __ 4 and the limeade with a
greater ratio of water to lime juice will have a weaker
flavor
Guided Practice
1
Distance (mi) 8 1 __ 2 17 25 1 __
2 34 42 1 __
2
Time (h) 1 __ 2 1 1 1 __
2 2 2 1 __
2
2 3 1 __ 2 miles divide ( 1 1 __
4 hours ) = 7 __
2 divide 5 __
4 mi ___ h
= 7 times 4 _____ 2 times 5
= 1 7 times 4 _____ 2 times 5
2
= 7 times 2 _____ 1 times 5
= 14 ___ 5 mi ___
h
= 2 4 __ 5 miles per hour
3 5 __ 8 page divide ( 2 __
3 minute ) = 5 __
8 times 3 __
2
= 15 ___ 16
page per minute
4 1 __ 6 foot divide ( 1 __
3 hour ) = 1 __
6 times 3 __
1
= 2 1 times 3 _____ 6 times 1
1
= 1 times 1 _____ 2 times 1
= 1 __ 2 foot per hour
5 5 __ 8 sq ft divide ( 1 __
4 hour ) = 5 __
8 times 4 __
1
= 2 5 times 4 _____ 8 times 1
1
= 5 times 1 _____ 2 times 1
= 5 __ 2 or 2 1 __
2 square feet per hour
Solutions KeyRatios and Proportional Relationships
UNIT
2
Copyright copy by Houghton Mifflin Harcourt 23 All rights reserved
6 240 milligrams divide ( 1 __ 3 pickle ) = 240 ____
1 divide 1 __
3
= 240 ____ 1 times 3 __
1
= 720 ____ 1
Brand Arsquos rate is 720 mg per pickle
325 milligrams divide ( 1 __ 2 pickle ) = 325 ____
1 divide 1 __
2
= 325 ____ 1 times 2 __
1
= 650 ____ 1
Brand Brsquos rate is 650 milligrams per pickle and is
therefore lower than Brand A
7 The unit rate for Ingredient C is
1 __ 4 cup divide ( 2 __
3 serving ) = 1 __
4 times 3 __
2
= 3 __ 8
cup _______
serving
The unit rate for Ingredient D is
1 __ 3 cup divide ( 3 __
4 serving ) = 1 __
3 times 4 __
3
= 4 __ 9
cup _______
serving
To compare 3 __ 8 to 4 __
9 find the least common
denominator of 8 and 9 so that 3 __ 8 = 27 ___
72 and 4 __
9 = 32 ___
72
Therefore ingredient Crsquos unit rate is lower
8 Divide the number in the numerator by the number
in the denominator Write the result with the units of
the rate
For example 1 mile ______
1 __ 2 hour
= 1 __
1 __ 2 = 2 miles per hour
Independent Practice
9 a The unit rate in dollars per hour for On Call is
$10 divide ( 35 hours ) = 10 ___ 35
$ __
h asymp $286 per hour
The unit rate in dollars per hour for Talk Time is
$125 divide ( 1 __ 2 hours ) = 125 ____
05 $ __
h asymp $250 per hour
b Talk Time offers the better deal because its rate in
dollars per hour is lower
c To convert dollars per minute to dollars per hour
multiply by 60
$005 divide ( 1 minute )
= 005 ____ 1
$ ____
min times 60 min ______
1 h
= $3 per hour
d $3 per hour is more expensive than either On Call
or Talk Time so it is not a better deal than either
one
10 a Sample answer 1 __ 2 cup dried fruit to 1 __
8 cup
sunflower seeds in a granola recipe
b The ratio would not change if the recipe were
tripled because both numbers in the ratio would
be multiplied by the same number and therefore
the ratio would still be equivalent to what it was
originally
c 1 __ 2 divide 1 __
8 = 1 ___
1 2 times 8
4 __
1 = 4 __
1 = 4
Sample answer 4 cups dried fruit per 1 cup
sunflower seeds
11 10 songs
____________ 2 commercials
= 5 songs ____________
1 commercials
12 a Terrancersquos rate
6 mi divide ( 1 __ 2 h ) = 6 __
1 times 2 __
1
= 12 miles per hour
Jessersquos rate
2 mi divide ( 15 min ) = 2 __ 1 divide 1 __
4
= 2 __ 1 times 4 __
1 mi ___ h
= 8 miles per hour
b Terrance
50 mi divide ( 12 mi ___ h ) = 50 ___
1 times 1 ___
12
= 50 ___ 12
h
= 4 1 __ 6 h
= 4 10 ___ 60
h
= 4 hours and 10 minutes
Jesse
50 mi divide ( 8 mi ___ h ) = 50 ___
1 times 1 __
8
= 50 ___ 8 h
= 6 1 __ 4 h
= 6 15 ___ 60
h
= 6 hours and 15 minutes
c 8 mi divide ( 45 min ) = 8 __ 1 divide 3 __
4
= 8 __ 1 times 4 __
3
= 32 ___ 3
= 10 2 __ 3 miles per hour
Sandrarsquos unit rate is greater than Jessersquos but
lower than Terrancersquos so she runs slower than
Terrance but faster than Jesse
13 1 ___ 10
h = 6 ___ 60
h = 6 min
300 words _________ 6 min
= 50 words per min
1 ___ 12
h = 5 ___ 60
h = 5 min
300 words _________ 5 min
= 60 words per min
Faster Eli typed 50 words per minute in his first test
and 60 words per minute in his second test
Copyright copy by Houghton Mifflin Harcourt 24 All rights reserved
Focus on Higher Order Thinking
14 a For the 10-pack of 21 ounce bars
$1537 divide 10 bars asymp $154 per bar
For the 12-pack of 14 ounce bars
$1535 divide 12 bars asymp $128 per bar
The 12-pack has the better price per bar
b For the 10-pack
$1537 divide ( 10 times 21 oz ) = 1537 divide 21
asymp $073 per ounce
For the 12-pack
$1535 divide ( 12 times 14 oz ) = 1535 divide 168
asymp $091 per ounce
The 10-pack has a better price per ounce
c Sample answer Since I always eat them one bar
at a time the 12-pack is the better choice
15 Yes Half a room in half a day corresponds to a unit
rate of 1 __ 2 room divide ( 1 __
2 day ) = 1 room _____
day so at the same
rate the painter could paint 7 rooms in 7 days
16 Sample answer Take the reciprocal of the rate For
example a rate of 7 gallons per hour is equal to
1 hour per 7 gallons
LESSON 42
Your Turn
3 No the rates are not equal and therefore her speed
was not constant
4 Since the ratio of students to adults is constant the
relationship between them is proportional
students ________ adults
= 12 ___ 1 = 36 ___
3 = 60 ___
5 = 12 students per adult
If s = the number of students and a = the number
of adults then a = 1 ___ 12
s or s = 12a
Guided Practice
1 45 ___ 1 = 45 90 ___
2 = 45 135 ____
3 = 45 180 ____
4 = 45
The relationship is proportional
2 k = y __ x = 10 ___
2 = 5 y = 5x
3 k = y __ x = 2 __
8 = 1 __
4 y = 1 __
4 x
4 With the equation y = kx where k is the constant
of proportionality
Independent Practice
5 k = y __ x = 74 ___
4 = 1850 y = 1850x
6 $1099
_______ 05 days
= $2198 per day
7 Rent-All because it has the lowest price per day
($1850)
8 100 ft _____ 08 s
= 1000 _____ 8 ft __ s = 125 ft __ s
500 ft _____ 31 s
= 5000 _____ 31
ft __ s asymp 1613 ft __ s
1875 ft ______ 15 s
= 1875 ______ 15
ft __ s asymp 125 ft __ s
No Emtiaz assumed the relationship is proportional
but it is not The rate of change is not constant and
so his answer is not reasonable
9 $3125
______ 5 h
= $625 per hour and $5000
______ 8 h
= $625 per
hour Because the two unit rates are the same the
relationship between charge and time is proportional
10 The constant rate of change in this context means
that Steven charges $625 per hour
11 y = $625x where x is the number of hours Steven
babysits and y is the amount Steven charges
12 y = $625 ( 3 ) = $1875
13 300 ft _____ 2 min
= 6750
_____ 45
= 150 feet per minute
150 ft _____ min
times 60 min ______ 1 h
= 9000 feet per hour
14 y = 150x
15 Sample answer Feet per minute A submarine may
stay submerged for hours but it would not dive for
hours
Focus on Higher Order Thinking
16 Yes because there is a proportional relationship
so the distance and the time would increase by the
same factor
17 Sample answer Yes Even though the rates in the
table are not constant per ear of corn due to
rounding there is a constant rate for every 3 ears
of corn
LESSON 43
Your Turn
1 No because 11 ___ 1 ne 16 ___
2 Also the line drawn through
the points does not go through the origin
5 a The point ( 4 60 ) represents that the bicyclist can
ride a distance 60 miles in 4 hours
b k = 60 mi _____ 4 h
= 15 mi ___ h
c y = 15x where x is time in hours and y is
distance in miles
Guided Practice
1
Time (h) 3 5 9 10
Pages 195 325 585 650
Proportional the rate is a constant 65 pages
per hour
2
Time (h) 2 3 5 8
Earnings 15 2250 3750 60
Proportional the rate of is a constant $750 per hour
Copyright copy by Houghton Mifflin Harcourt 25 All rights reserved
3 Not proportional the relationship is linear but a line
drawn connecting the points will not pass through
the origin of ( 0 0 )
4 Proportional a line can be drawn that passes
through the points and also the origin of ( 0 0 )
5 k = 28 ft ____ 8 s
= 7 __ 2 ft __ s = 35 ft __ s y = 7 __
2 x or y = 35x where
x = time in seconds and y = height in feet
6 k = $2 ______
8 items = 1 __
4
$ _____
items = 025
$ _____
items so y = 1 __
4 x or
y = 025x where x = number of items and
y = cost in dollars
7 The graph is a straight line passing through the
origin
Independent Practice
8 It is the distance ( 0 miles ) that each horse runs in
0 minutes
9 Horse A runs 1 mile in 4 minutes
Horse B runs 1 mile in 25 minutes
10 For Horse A y = 1 __ 4 x
For Horse B y = 1 ___ 25
x or 2 __ 5 x
11 If x is time in minutes and y is distance in miles in
12 minutes Horse A will run 3 miles or 1 __ 4 ( 12 ) = 3
and Horse B will run 48 miles or 2 __ 5 ( 12 ) = 24 ___
5 = 48
12 Students may draw any straight line with a slope
steeper than 2 __ 5 that starts at the origin of ( 0 0 ) An
example is given below
2
2
4
6
8
10
4 6 8 10Time (min)
Dis
tanc
e (m
i)
A
B
O
13 Yes if the train is traveling at a constant speed the
ratio of miles traveled to time in hours will be
constant and therefore a graph comparing miles to
hours will form a straight line that passes through
the origin of ( 0 0 )
14 Sample answer When comparing relationships that
may be easier to observe on a graph than in an
equation
15 a
2
8
16
24
32
40
4 6 8 10DVDs
Cost
($)
O
b Sample answer The graph will pass through the
point ( 4 20 ) This point shows that four DVDs will
cost $20
16 The graph passes through the point ( 4 8 ) so
Glenda swam 8 feet in 4 seconds
17 Yes The graph is linear and passes through the
origin and therefore the rate of distance to time is
proportional at each point on the line
18 k = 8 ft ___ 4 s
= 2 ft __ s so y = 2x where x is time in
seconds and y is distance swam in feet It would
take 22 minutes to swim 1 __ 2 mile at this rate
Focus on Higher Order Thinking
19 Divide the second coordinate by the first to find the
constant of proportionality k Substitute the value of
k into the equation y = kx Then choose a value for x
and solve for y to find the ordered pair
20 Car 3 is not traveling at a constant speed
because 65 ___ 1 ne 85 ___
2
21 Since Car 4 is traveling at twice the speed it will
travel twice the distance as Car 2 in the same
amount of time Therefore the values in Car 4rsquos
distance column will be twice that shown in Car 2rsquos
distance column
MODULE 4
Ready to Go On
1 $140
_____ 18 ft 2
= $778 per square foot
2 $299
_____ 14 lb
asymp $021 per pound
3 $56 ______
25 gal = $224 per gallon
$3205
______ 15 gal
asymp $214 per gallon this is the better deal
4 $160
_____ 5 g
= $3200 per gram this is the better deal
$315
_____ 9 g
asymp $3500 per gram
5 No The ratio of dollars earned to lawns mowed is
not constant 15 ___ 1 ne 48 ___
3
Copyright copy by Houghton Mifflin Harcourt 26 All rights reserved
6 k = $9
___ 8euro
= $27 ____
24euro = 9 __
8 $ __
euro or 1125
$ __
euro So y = 9 __
8 x or
y = 1125x where x equals the number of euros
and y equals their value in dollars
7 The graph passes through the point ( 2 5 )
so k = 5 __ 2 servings
_______ pt
or k = 25 servings
_______ pt
Therefore
y = 5 __ 2
x or y = 25x where x equals the number
of pints and y equals the number of servings
8 The new graph will pass through the points ( 0 0 ) and ( 3 2 )
2
2
4
6
8
10
4 6 8 10Pints
Serv
ings
Frozen Yogurt
O
Therefore y = 2 __ 3 x where x equals the number of
pints and y equals the number of servings
9 Sample answer Compare corresponding values of
the variables to determine whether there is a
constant rate
Copyright copy by Houghton Mifflin Harcourt 27 All rights reserved
MODULE 5 Proportions and Percent
Are You Ready
1 22 = 22 ____ 100
= 022
2 75 = 75 ____ 100
= 075
3 6 = 6 ____ 100
= 006
4 189 = 100 + 89
= 100 ____ 100
+ 89 ____ 100
= 1 + 089
= 189
5 059 = 59
6 098 = 98
7 002 = 2
8 133 = 133
9 64
_ timesthinsp05
320
32
10 30
_ timesthinsp007
210
21
11 160
_ timesthinsp015
800
_ +1600
2400
24
12 62
_ timesthinsp032
124
_ +thinsp1860
1984
1984
13 4
_ timesthinsp12
8
_ +thinsp40
48
48
14 1000
_ timesthinsp006
6000
60
LESSON 51
Your Turn
2 x = ( $64 - 52 )
__________ $52
x = $12
____ $52
asymp 23
4 x = ( 18 - 12 )
________ 18
x = 6 ___ 18
asymp 33
5 x = ( 16 - 10 )
________ 16
x = 6 ___ 16
= 375
8 010 times $499 = $4990
$499 + $4990 = $54890
9 030 times $499 = $14970
$499 - $14970 = $34930
Guided Practice
1 x = ( $8 - $5 )
_________ $5
x = $3
___ $5
= 60
2 x = ( 30 - 20 )
_________ 20
x = 10 ___ 20
= 50
3 x = ( 150 - 86 )
__________ 86
x = 64 ___ 86
asymp 74
4 x = ( $389 - $349 )
______________ $349
x = $040
_____ $349
asymp 11
5 x = ( 14 - 13 )
________ 13
x = 1 ___ 13
asymp 8
6 x = ( 16 - 5 )
________ 5
x = 11 ___ 5 = 220
7 x = ( 64 - 36 )
_________ 36
x = 28 ___ 36
asymp 78
8 x = ( 80 - 64 )
_________ 80
x = 16 ___ 80
= 20
9 x = ( 95 - 68 )
_________ 95
x = 27 ___ 95
asymp 28
Copyright copy by Houghton Mifflin Harcourt 28 All rights reserved
10 x=( 90-45)_________
90
x=45___90
=50
11 x=( 145-132)__________
145
x=13____145
asymp9
12 x=( 64-21)_________
64
x=43___64
asymp67
13 x=( 16-0)________
16
x=16___16
=100
14 x=( 3-1__
2)_______
3
x=21__
2___
3 asymp83
15 010times$900=$090 $900+$090=$990
16 025times48=12 48-12=36cookies
17 020times340=68 $340-68=272pages
18 050times28=14 28+14=42members
19 004times$29000=$1160 $29000-$1160=$27840
20 130times810=1053 810+1053=1863songs
21 030times20=6 20+6=26miles
22 Dividetheamountofchangeinthequantitybytheoriginalamountthenexpresstheanswerasapercent
Independent Practice23
ItemOriginal
PriceNew Price
Percent Change
Increase or
DecreaseBike $110 $96 asympthinsp13 Decrease
Scooter $45 $56 asympthinsp24 Increase
TennisRacket $79 $8295 5 Increase
Skis $580 $435 25 Decrease
24 a 55
x=( 8-3)_______
8 =5__
8=625
x=( 12-7)________
12 =5___
12asymp417
Theamountofchangeisthesamebutthepercentofchangeislessfrom2010to2011
b Changewasgreatestbetween2009and2010
x=( 12-3)________
3
x=9__3=300increase
25 a Amountofchange=( 5-4)=1
Percentdecrease=1__5=20
b $100_____5 =$020each$100_____
4 =$025each
Amountofchange=$025-$020=$005
Percentincrease=$005_____$020
=25
26 Percenterror=( 136-133)___________
136 times100
=03____136
times100asymp2
Focus on Higher Order Thinking
27 a Theyhavethesame$100+$10=$110and$100+10( $100)=$110
b SylviahasmoreLeroihas$110+$10=$120andSylviahas$110+10( $110)=$121
c BecauseSylviawillhavemoreafterthesecondadditionaldepositandshewillbedepositingincreasingamountsshewillalwayshavemoreinheraccount
28 Thefinalamountisalways0becausea100decreaseofanyamountwouldbe0
29 NoOnlythefirstwithdrawalis$10Eachwithdrawalafterthatislessthan$10becauseitis10oftheremainingbalanceTherewillbemoneyleftafter10withdrawals
LESSON 52
Your Turn
2 a 1c+01c11c
b s=11times$28=$3080
3 a 200
b 1c+2c3c
5 a
1b - 024b
1b024b
b 1b-024b=076b
6 a 1p-005p095p
b 095p=$1425
CopyrightcopybyHoughtonMifflinHarcourt 29 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U2M05indd 29 103113 214 AM
Guided Practice
1 a 035s
b 1s + 035s 135s
c 135 times $3200 = $4320
d 035 times $3200 = $1120
Item Price Markup MarkupRetail
Price
2 Hat $18 15 $270 $2070
3 Book $2250 42 $945 $3195
4 Shirt $3375 75 $2531 $5906
5 Shoes $7499 33 $2475 $9974
6 Clock $4860 100 $4860 $9720
7 Painting $18500 125 $23125 $41625
8 $4500 - 022 ( $4500 ) = $3510
9 $8900 - 033 ( $8900 ) = $5963
10 $2399 - 044 ( $2399 ) = $1343
11 $27999 - 075 ( $27999 ) = $7000
12 Write the percent of markdown as a decimal
subtract the product of this decimal and the regular
price from the regular price
Independent Practice
13 a 046b
b 1b - 046b 054b
c 054 times $2900 = $1566
d 046 times $2900 = $1334
14 Regular Price $329
Sale Price $201
Regular Price $419
Sale Price $245
Regular Price $279
Sale Price $115
Regular Price $309
Sale Price $272
Regular Price $377
Sale Price $224
15 a Sample answer original price $100 final price
$050
b Sample answer original price $100 final price
$9950
c Sample answer original price $100 final price
$350
16 p = 127 ( $7400 ) = $9398
s = 127 ( $4800 ) = $6096
j = 127 ( $32500 ) = $41275
2 ( 9398 ) + 3 ( $6096 ) + $41275 = $78359
17 Either buy 3 get one free or 1 __ 4 off Either case would
result in a discount of 25 which is better than 20
Focus on Higher Order Thinking
18 No she is taking a loss Her cost for the tea is t so
the retail price is 12t The discounted price is
08 ( 12t ) or 096t which is less than t
19 No first change 201 decrease second change
251 increase The second percent change is
greater
20 Rafael can purchase the coat after 11 or 12 weeks
after 11 weeks the price is $10932 after 12 weeks
the price is $10385 and after that Danielle donates
the coat
LESSON 53
Your Turn
1 005 times $2000 = $100 $100 + $2000 = $2100
3 005 times $40000 = $2000
$2000 times 4 years = $8000
$40000 + $8000 = $48000
4 Commission $4500 times 00375 = $16875
Total $2200 + $16875 = $236875
Guided Practice
1 005 times $3000 = $150
2 015 times $7000 = $1050
3 0004 times $10000 = $040
4 15 times $2200 = $3300
5 001 times $8000 = $080
6 20 times $500 = $1000
7 a 007 times $4399 = $308
b $4399 + $308 = $4707
8 115 times $7550 = $8683
9 007 times $2000 = $140
$140 times 5 years = $700
10 003 times $550 = $1650
$1650 times 10 years = $165
$550 + $165 = $715
11 a 090 times $20 = $18
b 1085 times $18 = $1953
12 020 times $2999 = $600 tip
00625 times $2999 = $187 tax
$2999 + $600 + $187 = $3786 total
13 Write the tax rate as a decimal Then multiply the
decimal by the price of the item and add the result
to the price
Independent Practice
14 $3275 + $3988 = $7263 total meal cost
014 times $7263 = $1017 tip
$7263 + $1017 = $8280 total with tip
15 $7865 times 015 = $1180 meal discount
$7865 times 020 = $1573 tip
$7865 + $1573 - $1180 = $8258 total
16 $125 times 235 = $29375 retail ring cost
0075 times $29375 = $2203 tax
$29375 + $2203 = $31578 total with tax
Copyright copy by Houghton Mifflin Harcourt 30 All rights reserved
17 $7999 times 012 = $960 discount
$7999 - $960 = $7039 price before tax
$7039 times 10675 = $7514 total with tax
18 4 times $999 times 020 = $799 discount
4 times $999 - $799 = $3197 price before tax
$3197 times 10675 = $3413 total with tax
19 $4500 + 00725 = $32625 commission
$750 + $32625 = $107625 total income
20 $700 times 0055 = $3850 commission
$475 + $3850 = $51350 total income
21 a Multiply Sandrarsquos height by 010 and add the
product to 4 to get Pablorsquos height Then multiply
Pablorsquos height by 008 and add the product to
Pablorsquos height to get Michaelarsquos height
b Using 48 inches for 4 feet
48 inches times 01 = 48 inches so Pablorsquos height is
53 inches or 4 feet 5 inches to the nearest inch
53 inches times 008 = 42 inches so Michaelarsquos
height is 57 inches or 4 feet 9 inches to the
nearest inch
22 a $4998 times 05 = $2499 50 discount
$2499 - $1000 = $1499 $10 discount
b $4998 - $1000 = $3998 $10 discount
$3998 times 05 = $1999 50 discount
23 a $95 times 09 = $8550 discounted camera
$8550 + $1599 = $10149 total
b $1599 times 09 = $1439 discounted battery
$95 + $1439 = $10939 total
c Eric should apply the discount to the digital
camera he can save $8
d $10149 times 008 = $812 tax
$10149 + $812 = $10961 total
24 a Store 1 $22 divide 2 = $11
Store 2 $1299 times 09 = $1169
Store 1 charges $11 per shirt and Store 2
charges $1169 Therefore I would save
$069 per shirt at Store 1
b Store 3 $2098 times 045 = $944
Yes It is selling shirts at $944
Focus on Higher Order Thinking
25 Marcus should choose the option that pays $2400
plus 3 of sales He would make $2550 to $2700
per month The other option would pay only $1775
to $2050 per month
26 Percent error = ǀ 132 - 137 ǀ
____________ 137
times 100 = 05 ____ 137
asymp 36
MODULE 5
Ready to Go On
1 x = ( 63 - 36 )
_________ 36
x = 27 ___ 36
= 75 increase
2 x = ( 50 - 35 )
_________ 50
x = 15 ___ 50
= 30 decrease
3 x = ( 72 - 40 )
_________ 40
x = 32 ___ 40
= 80 increase
4 x = ( 92 - 69 )
_________ 92
x = 23 ___ 92
= 25 decrease
5 $60 times 015 = $9
$60 + $9 = $69
6 $32 times 0125 = $4
$32 + $4 = $36
7 $50 times 022 = $11
$50 - $11 = $39
8 $125 times 030 = $3750
$12500 - $3750 = $8750
9 $4800 times 0065 = $312 commission
$325 + $312 = $637 total income
10 $5310
______ $1735
asymp 31
11 Find the amount per hour that Priya makes if she
makes 20 more than James
$700 times 020 = $140
$700 + $140 = $840
Next find the amount Slobhan makes if he makes
5 less than Priya
$840 times 005 = $042
$840 - $042 = $798
Slobhan makes $798 per hour
12 Both the 6 tax and the 20 tip are applied to the
initial cost of the meal so the two percents can be
added together and multiplied by the cost
$45 times 026 = $1170
$45 + $1170 = $5670
The total cost of the meal is $5670
13 Sample answer sales tax increase discount
decrease tip increase
Copyright copy by Houghton Mifflin Harcourt 31 All rights reserved
MODULE 6 Expressions and Equations
Are You Ready
1 5 + x
2 11 - n
3 -9 ___ y
4 2x - 13
5 2x + 3
= 2 ( 3 ) + 3
= 6 + 3
= 9
6 -4x + 7
= -4 ( 1 ) + 7
= -4 + 7
= 11
7 15x - 25
= 15 ( 3 ) - 25
= 45 - 25
= 2
8 04x + 61
= 04 ( -5 ) + 61
= -20 + 61
= 41
9 2 __ 3 x - 12
= 2 __ 3
( 18 ) - 12
= 2 __ 3
times ( 18 ___ 1 ) - 12
= 36 ___ 3 - 12
= 0
10 - 5 __ 8
x + 10
= - 5 __ 8 ( -8 ) + 10
= - 5 __ 8 times- 8 __
1 + 10
= - 5 ___ 1 8
times- 8 1 __
1 + 10
= - 5 __ 1 times- 1 __
1 + 10
= 5 + 10
= 15
11 1 __ 2 divide 1 __
4
= 1 times 4 _____ 2 times 1
= 1 times 4 2 ______
1 2 times 1
= 1 times 2 _____ 1 times 1
= 2
12 3 __ 8 divide 13 ___
16
= 3 __ 8 times 16 ___
13
= 3 times 16 2 _______
1 8 times 13
= 3 times 2 ______ 1 times 13
= 6 ___ 13
13 2 __ 5 divide 14 ___
15
= 2 __ 5 times 15 ___
14
= 1 2 times 15
3 ________
1 5 times 14 7
= 1 times 3 _____ 1 times 7
= 3 __ 7
14 4 __ 9 divide 16 ___
27
= 4 __ 9 times 27 ___
16
= 1 4 times 27
3 ________
1 9 times 16 4
= 1 times 3 _____ 1 times 4
= 3 __ 4
LESSON 61
Your Turn
2 ( 3x + 1 __ 2 ) + ( 7x - 4 1 __
2 )
= 3x + 7x + 1 __ 2 - 4 1 __
2
= 10x - 4
3 ( -025x - 3 ) - ( 15x + 14 ) = -025x - 3 - 15x - 14
= -175x - 44
4 02(3b - 15c) + 6c
= 06b - 3c + 6c
= 06b + 3c
5 2 __ 3 (6e + 9f - 21g) - 7f
= 4e + 6f - 14g - 7f
= 4e - f - 14g
6 5x - 3(x - 2) - x
= 5x - 3x + 6 - x
= x + 6
7 83 + 34y - 05(12y - 7)
= 83 + 34y - 6y + 35
= 118 - 26y
Solutions KeyExpressions Equations and Inequalities
UNIT
3
Copyright copy by Houghton Mifflin Harcourt 32 All rights reserved
Guided Practice
1 baseballs 14 + (12)n tennis balls 23 + (16)n
14 + 12n + 23 + 16n
14 + 23 + 12n + 16n
37 + 28n
So the total number of baseballs and tennis balls is
37 + 28n
2 37 + 28n
37 + 28 ( 9 )
= 37 + 252
= 289
3 14 + 5(x + 3) - 7x = 14 + 5x + 15 - 7x
= 29 - 2x
4 3 ( t - 4 ) - 8 ( 2 - 3t ) = 3t - 12 - 16 + 24t
= 27t - 28
5 63c - 2 ( 15c + 41 ) = 63c - 3c - 82
= 33c - 82
6 9 + 1 __ 2 ( 7n - 26 ) - 8n = 9 + 35n - 13 - 8n
= -4 - 4 1 __ 2 n
7 2x + 12
2 ( x + 6 )
8 12x + 24
12 ( x + 2 )
9 7x + 35
7 ( x + 5 )
10 You multiply numbers or expressions to produce a
product You factor a product into the numbers or
expressions that were multiplied to produce it
Independent Practice
11 Let d = number of days
Fee for 15 food booths 15 ( 100 + 5d ) Fee for 20 game booths fee 20 ( 50 + 7d ) Amount the company is paid for the booths
15 ( 100 + 5d ) + 20 ( 50 + 7d ) = 15 ( 100 ) + 15 ( 5d ) + 20 ( 50 ) + 20 ( 7d )
= 1500 + 75d + 1000 + 140d
= 1500 + 1000 + 75d + 140d
= 2500 + 215d
12 New length 96 + l
New width 60 + w
Perimeter of new pattern
2(96 + l) + 2(60 + w)
=2(96) + 2l + 2(60) + 2w
192 + 2l + 120 + 2w
192 + 120 + 2l + 2w
312 + 2l + 2w
13 Width 3
Length 1 x-tile and 2 +1-tiles
Factors 3 and x + 2
Product 3 ( x + 2 ) = 3x + 6
14 Width 4
Length 2 x-tiles and 1 -1-tile
Factors 4 and 2x - 1
Product 4 ( 2x - 1 ) = 8x - 4
15 The area is the product of the length and width
( 6 times 9 ) It is also the sum of the areas of the
rectangles separated by the dashed line ( 6 times 5
and 6 times 4 ) So 6 ( 9 ) = 6 ( 5 ) + 6 ( 4 )
16 Perimeter of triangle ( x + 3 ) + ( 2x + 4 ) +
6x = ( x + 3 ) + ( 2x + 4 ) +
6x = 3x + 7 +
-3x = _ -3x
3x = 7 +
_ -7 = _ -7
3x - 7 =
The length of the side is 3x - 7
17 Perimeter of rectangle 2 ( 3x - 3 ) + 2 ( )
10x + 6 = 2 ( 3x - 3 ) + 2 ( )
10x + 6 = 6x - 6 + 2
_ -6x = _ -6x
4x + 6 = - 6 + 2
_ + 6 = _ + 6
4x + 12 = 2
( 4x + 12 ) divide 2 = ( 2 ) divide 2
2x + 6 =
The length of the side is 2x + 6
18 a P = 2l + 2w
Perimeter of tennis court T
2(2x + 6) + 2(x)
= 4x + 12 + 2x
= 6x + 12
Perimeter of basketball court B
2(3x - 14) + 2( 1 __ 2 x + 32)
= 6x - 28 + x + 64
= 7x + 36
b (7x + 36) - (6x + 12)
= 7x + 36 - 6x - 12
= x + 24
c Find the length of tennis court
Let x = 36
2x + 6 = 2 ( 36 ) + 6
= 72 + 6
= 78
Find the width of the basketball court
Let x = 36
1 __ 2 x + 32 = 1 __
2 ( 36 ) + 32
= 18 + 32
= 50
Find the length of the basketball court
Let x = 36
3x - 14 = 3 ( 36 ) - 14
= 108 - 14
= 94
The tennis court is 36 ft by 78 ft The basketball
court is 50 ft by 94 ft
Focus on Higher Order Thinking
19 Find the area of each small square and rectangle
( x ) ( x ) = x 2
( x ) 1 = x
( 1 ) 1 = 1
Copyright copy by Houghton Mifflin Harcourt 33 All rights reserved
x
x
1
11
1 1
x2 x x x
x 1 1 1x 1 1 1
Area =
x 2 + x + x + x + x + x + 1 + 1 + 1 + 1 + 1 + 1
= x 2 + 5x + 6
( x + 3 ) ( x + 2 ) = x 2 + 5x + 6
20 Agree To find 58 times 23 let 23 = 3 + 20 Then find
the product 58 ( 3 + 20 ) First step 58 ( 3 ) = 174
Second step 58 ( 20 ) = 1160 Third step 174 +
1160 = 1334 So 58 ( 23 ) = 58 ( 3 ) + 58 ( 20 )
21 ( 1 ) Think of 997 as 1000 - 3 So 8 times 997 = 8 ( 1000 - 3 ) By the Distributive Property
8 ( 1000 - 3 ) = 8000 - 24 = 7976
( 2 ) Think of 997 as 900 + 90 + 7 By the Distributive
Property 8 ( 900 + 90 + 7 ) = 7200 + 720 + 56 =
7976
LESSON 62
Your Turn
1 49 + z = -9
_ -49 _ -49
z = -139
2 r - 171 = -48
_ +171 _ +171
r = 123
3 -3c = 36
-3c ____ -3
= 36 ___ -3
c = -12
5 x - 15 = 525
_ +15 _ +15
x = 675
The initial elevation of the plane is 675 miles
6 x ___ 35
= -12
x ___ 35
( 35 ) = -12 ( 35 )
x = -42
The decrease in the value of the stock was $420
7 25x = 75
25x ____ 25
= 75 ___ 25
x = 3
The power was restored in 3 hours
Guided Practice
1 Let x represent the number of degrees warmer the
average temperature is in Nov than in Jan
x + ( -134 ) = -17 or x - 134 = -17
x - 134 = -17
_ +134 _ +134
x = 117
The average temperature in November is 117degF
warmer
2 Let x represent the number of days it takes the
average temperature to decrease by 9degF
-1 1 __ 2 x = -9
( - 2 __ 3 ) ( - 3 __
2 x ) = ( - 2 __
3 ) ( -9 )
x = 18 ___ 3
x = 6
It took 6 days for the temperature to decrease by 9degF
3 -2x = 34
-2x ____ -2
= 34 ___ -2
x = -17
4 y - 35 = -21
_ + 35 _ + 35
y = 14
y = 14
5 2 __ 3 z = -6
( 3 __ 2 ) 2z ___
3 = ( 3 __
2 ) ( -6 )
z = -9
6 Sample answer It helps me describe the problem
precisely and solve it using inverse operations
Independent Practice
7 Let x equal the elevation of Mt Everest
x - 870737 = 203215
_ +870737 _ +870 737
x = 2902887
The elevation of Mt Everest is 2902887 ft
8 Let x equal the number of feet Liam descended
2825131 - x = 2320106
_ -2825131 _ -2825131
-x = - 505025
x = 505025
Liam descended 505025 ft
His change in elevation was -505025 ft
9 Let x equal the elevation of Mt Kenya
2825131 - x = 1119421
_ -2825131 _ -2825131
-x = -1705710
x = 1705710
The elevation of Mt Kenya is 170571 ft
10 Find the change in elevation
1250 - 935 = 315
Use an equation
Let x = the number of minutes the balloon
descends
( -22 1 __ 2 ) x = -315
( - 45 ___ 2 ) x = -315
( - 2 ___ 45
) ( - 45 ___ 2 ) x = -315 ( - 2 ___
45 )
x = 14
It will take the balloon 14 minutes to descend
11 Find the change in elevation
4106 - 3205 = 901
Use an equation to find the rate of descent
Copyright copy by Houghton Mifflin Harcourt 34 All rights reserved
Let x = rate of descent
34x = 901
34x ____ 34
= 901 ____ 34
x = 265 = 26 1 __ 2
The rate of descent was 26 1 __ 2 feet per minute
12 Let x = the number of degrees warmer Montanarsquos
average temperature is than Minnesotarsquos
- 25 + x = -07
_ + 25 _ + 25
x = 18
Montanarsquos average 3-month temperature is 18degC
warmer than Minnesotarsquos
13 Let x = the number of degrees warmer Floridarsquos
average temperature is than Montanarsquos
181 - x = -07
_ - 181 _ -181
-x = -188
x = 188
Floridarsquos average 3-month temperature is 188degC
warmer than Montanarsquos
14 Let x = the number of degrees the average
temperature in Texas would have to change
125 + x = 181
_ -125 _ -125
x = 56
It would have to increase by 56degC
15 Let x = the number of yards the team must get on
their next play
-26 1 __ 3
+ x = 10
+26 1 __ 3
______
+26 1 __ 3
______
x = 36 1 __ 3
The team needs to get 36 1 __ 3 yards on their next play
16 Let x = the number of seconds
( -2 1 __ 2 ) x = -156
( -25 ) x = -156
( -25 _____ -25
) x = -156 ______ -25
x = 624
It takes the diver 624 seconds to reach -156 feet
17 Sample answer The elevation is the product of the
rate and the time
18 Let x = the total amount withdrawn
x __ 5 = 455
( 5 ) x __ 5 = 455 ( 5 )
x = 2275
The total amount she withdrew was $22750
Sample answer
$4550 asymp $50 and $50 times 5 = $250 which is close
to $22750
Focus on Higher Order Thinking
19 ( 1 ) The elevations of the diver and the reef both are
below sea level
( 2 ) The change in the planersquos elevation the plane
descends the plane is moving from a higher to a
lower elevation
20 -4x = -48
( -4x ____ -4
) = -48 _____ -4
x = 12
- 1 __ 4 x = -48
( -4 ) ( - 1 __ 4 ) x = -48 ( -4 )
x = 192
192 ____ 12
= 16
In the first case -4x = -48 you divide both sides
by -4 In the second - 1 __ 4 x = -48 you multiply
both sides by -4 The second solution (192) is
16 times the first (12)
21 Add the deposits and the withdrawals Let x repre-
sent the amount of the initial deposit Write and
solve the equation x + deposits - withdrawals =
$21085
LESSON 63
Your Turn
4 Let x represent the number of video games Billy
purchased
Original balance on gift card $150
Cost for x video games $35 middot x
Final balance on gift card $45
Original balance minus $35 times number of games equals $45
darr darr darr darr darr darr darr $150 - $35 middot x = $45
Equation 150 - 35x = 45
5 Sample answer You order x pounds of coffee from
Guatemala at $10 per pound and it costs $40 to
ship the order How many pounds can you order so
that the total cost is $100
Guided Practice
1
+ + ++ ++
+++ + +
+++
2
----
+ ++ ++
- - -
Copyright copy by Houghton Mifflin Harcourt 35 All rights reserved
3 Let a represent the number of adults that attend
Ticket cost for 1 child = $6
Ticket cost for a adults = $9 middot a
Total cost for movie = $78
cost for child plus $9 times number of adults equals $78
darr darr darr darr darr darr darr $6 + $9 middot a = $78
Equation 6 + 9a = 78
4 x is the solution of the problem
2x is the quantity you are looking for multiplied by 2
+ 10 means 10 is added to 2x
= 16 means the result is 16
5 Sample answer A department store is having a sale
on recliners buy two and get a discount of $125
Sanjay purchases two recliners and the total cost
(before taxes) is $400 What is the price of a single
recliner not including any discounts
6 Choose a variable to represent what you want to
find Decide how the items of information in the
problem relate to the variable and to each other
Then write an equation tying this all together
Independent Practice
7 On one side of a line place three negative variable
tiles and seven +1-tiles and then on the other side
place 28 +1-tiles
8 Let d represent the number of days Val rented the
bicycle
Flat rental fee $5500
Cost for d days of rental $850 middot dTotal cost $123
$850 times number of days plus flat fee equals total cost
darr darr darr darr darr darr darr $850 bull d + $55 = $123
Equation 85d + 55 = 123
9 Let r represent the number of refills
Refill mug cost $675
Cost for r refills $125 middot r Total cost $3175
$125 times number of refills plus refill mug cost equals total cost
darr darr darr darr darr darr darr $125 bull r + $675 = $3175
Equation 125r + 675 = 3175
10 Let n represent the number of weekday classes
The Saturday class lasts 60 minutes
The length of time for the weekday classes is 45 middot n
The total number of minutes for all classes in a week
is 28545 minutes times number of plus minutes for equals total minutes
weekday classes Saturday class
darr darr darr darr darr darr darr45 bull n + 60 = 285
Equation 45n + 60 = 285
11 Let n represent the number of African animals
Half the number of African animals is 1 __ 2 n
45 more than the number of African animals
means + 45
The total number of animals is 172
half times number of and 45 more than number equals total number
African animals of African animals of animals
darr darr darr darr darr darr
1 _ 2
bull n + 45 = 172
Equation 1 __ 2 n + 45 = 172
12 Let u represent the number of uniforms
Cost for basketball equipment $548
Cost for u uniforms $2950 middot uTotal cost $2023
$2950 times number of plus cost for basketball equals total cost
uniforms equipment
darr darr darr darr darr darr darr $2950 bull u + $548 = $2023
Equation 295u + 548 = 2023
13 Let x represent the number of weeks
Initial amount in account $500
$20 per week 20 middot xFinal amount in account $220
initial amount minus 20 times number of equals final amount
weeks
darr darr darr darr darr darr darr 500 - 20 bull x = 220
Equation 500 - 20x = 220
14 a The equation adds 25 but Deenarsquos scenario
involves subtracting 25
b Let x represent the number of shirts
Cost of shirts before discount 9 middot xDiscount means subtract
Amount of discount $25
Total bill $88
9 times number of minus discount equals total
shirts bill
darr darr darr darr darr darr darr 9 bull x - 25 = 88
Equation 9x - 25 = 88
c Sample answer I bought some shirts at the store
for $9 each and a pair of jeans for $25 making
my bill a total of $88 How many shirts did I buy
15 a Let c represent the number of children
Flat fee for Sandy $10
Cost per child for Sandy $5 middot cTotal charge for Sandy $10 + $5c
Total charge for Kimmi $25
To compare the two costs set these values equal
Equation 10 + 5c = 25
b Solve the equation to find c the number of
children a family must have for Sandy and Kimmi
to charge the same amount
10 + 5c = 25
10 - 10 + 5c = 25 - 10
5c = 15
5c ___ 5 = 15 ___
5
c = 3
3 children
c They should choose Kimmi because she charges
only $25 If they chose Sandy they would pay
10 + 5 ( 5 ) = $35
Copyright copy by Houghton Mifflin Harcourt 36 All rights reserved
Focus on Higher Order Thinking
16 To get Andresrsquo equation you can multiply every
number in Peterrsquos equation by 4 To get Peterrsquos
equation you can divide every number in Andrewrsquos
equation by 4 or multiply by 1 __ 4
17 Part of the equation is written in cents and part in
dollars All of the numbers in the equation should be
written either in cents or dollars
18 Sample answer Cici has a gift card with a balance
of 60 She buys several T-shirts for $8 each Her new
balance is $28 after the purchases Write an
equation to help find out how many T-shirts Cici
bought
LESSON 64
Your Turn
1 Model the equation
+ ++ +
+ ++ ++ +
+ ++ ++ +
++
Remove 5 +1-tiles from each side of the mat
+ ++ +
+ ++ ++ +
+ ++ ++ +
++
Divide each side into two equal groups
++
+ ++ +
++
The solution is x = 3
++ ++
2 Model the equation
+ + ++ + ++ +
+++
+++
__
Add 1 +1-tile to each side of the mat Note that
a negative-positive tile pair results in zero
+ + ++ + ++
++ +
+++
+++
__
Divide each side into two equal groups
+ + ++++ + +++
The solution is n = 3
+ + +++
3 Model the equation
++++
______
______
____
Add 3 +1-tiles to each side of the mat Note that
a negative-positive tile pair results in zero
++++
+
++
+
++
______
______
____
Divide each side into two equal groups
++++
____
The solution is a = -1
++ __
Copyright copy by Houghton Mifflin Harcourt 37 All rights reserved
4 Model the equation
____
________
++
Add 2 -1-tiles to each side of the mat Note that
a negative-positive tile pair results in zero
________
________
++
____
Divide each side into two equal groups
________
________
We get -y = -1
____
In order to change -y to y add a positive y-variable
tile to each side
++
__ ++ __
Add 1 +1-tile to each side of the mat
++++
__
The solution is y = 1
+++
6 3n + 10 = 37
Solve the equation for n
3n + 10 = 37
-10 ____
-10 ____
3n = 27
3n ___ 3 = 27 ___
3
n = 9
The triplets are 9 years old
7 n __ 4 - 5 = 15
Solve the equation for n
n __ 4 - 5 = 15
+5 ___
+5 ___
n __ 4 = 20
n __ 4 ( 4 ) = 20 ( 4 )
n = 80
The number is 80
8 -20 = 5 __ 9 ( x - 32 )
Solve the equation for x
-20 = 5 __ 9 ( x - 32 )
-20 = 5 __ 9 x - 160 ____
9
+ 160 ____ 9
______
+ 160 ____ 9
______
- 20 ___ 9 = 5 __
9 x
- 20 ___ 9 divide ( 5 __
9 ) = 5 __
9 x divide ( 5 __
9 )
4 20 times 9
1 _______
9 1 times 5
1 = x
- 4 __ 1 = x
-4 = x
The temperature in the freezer is -4degF
9 120 - 4x = 92
Solve the equation for x
120 - 4x = 92
-120 _____
-120 _____
- 4x = -28
-4x ____ -4
= -28 ____ -4
x = 7
She had 7 incorrect answers
Copyright copy by Houghton Mifflin Harcourt 38 All rights reserved
Guided Practice
1 To solve the equation with algebra tiles first remove
one +1-tile from both sides Then divide each side
into two equal groups
2 Remove 1 +1-tile from each side
++++
+ +++++++++
Divide each side into two equal groups
++++
++++++++
The solution is x = 4
++ + + + +
3 Let w = the width of the frame
2 times height plus 2 times width equals perimeter
darr darr darr darr darr darr darr darr darr2 bull 18 + 2 bull w = 58
Solve the equation
2 ( 18 ) + 2w = 58
36 + 2w = 58
36 - 36 + 2w = 58 - 36
2w = 22
2w ___ 2 = 22 ___
2
w = 11
The width is 11 inches
4 1200 minus 25x = 500
Solve the equation for x
1200 - 25x = 500
_ -1200 _ -1200
-25x = -700
-25x _____ -25
= -700 _____ -25
x = 28
The manager will reorder in 28 days
5 Use the inverse operations of the operations
indicated in the problem If the equation does
not involve parentheses use addition or subtraction
before multiplication or division to solve the
equation
Independent Practice
6 9s + 3 = 57
9s + 3 - 3 = 57 - 3
9s = 54
9s ___ 9 = 54 ___
9
s = 6
7 4d + 6 = 42
4d + 6 - 6 = 42 - 6
4d = 36
4d ___ 4 = 36 ___
4
d = 9
8 115 - 3y = -485
115 - 115 - 3y = -485 - 115
thinsp-3y = -60
-3y
____ -3
= -60 ____ -3
y = 20
9 k __ 2 + 9 = 30
k __ 2 + 9 - 9 = 30 - 9
k __ 2 = 21
2 sdot k __ 2 = 2 sdot 21
k = 42
10 g
__ 3 - 7 = 15
g
__ 3 - 7 + 7 = 15 + 7
g
__ 3 = 22
3 sdot g
__ 3 = 3 sdot 22
g = 66
11 z __ 5 + 3 = -35
z __ 5 + 3 - 3 = -35 - 3
z __ 5 = -38
5 sdot z __ 5 = 5 ( -38 )
z = -190
12 -9h - 15 = 93
-9h - 15 + 15 = 93 + 15
-9h = 108
-9h ____ -9 = 108 ____
-9
h = -12
13 - 1 __ 3 (n + 15) = -2
- 1 __ 3 n - 5 = -2
- 1 __ 3 n - 5 + 5 = -2 + 5
- 1 __ 3 n = 3
-3 sdot - 1 __ 3 n = -3 sdot 3
n = -9
14 -17 + b __ 8 = 13
-17 + 17 + b __ 8 = 13 + 17
b __ 8 = 30
8 sdot b __ 8 = 8 sdot 30
b = 240
Copyright copy by Houghton Mifflin Harcourt 39 All rights reserved
15 7 ( c - 12 ) = -21
7c - 84 = -21
_ +84 _ +84
7c = 63
7c ___ 7 = 63 ___
7
c = 9
16 -35 + p
__ 7 = -52
-35 + 35 + p
__ 7 = -52 + 35
p
__ 7 = -17
7 sdot p
__ 7 = -17 sdot 7
p = -119
17 46 = -6t - 8
46 + 8 = -6t - 8 + 8
54 = -6t
54 ___ -6
= -6t ____ -6
t = -9
18 Let a = the original amount in the account
Double the (original plus 26) equals new
sum of amount amount
darr darr darr darr darr darr
2 (a + $26) = $264
Solve the equation
2 ( a + 26 ) = 264
2 ( a + 26 )
_________ 2 = 264 ____
2
a + 26 = 132
a + 26 - 26 = 132 - 26
a = 106
Puja originally had $106 in the account
19 Let t = the temperature 6 hours ago
Twice temperature less 6 degrees equals current
6 hours ago temperature
darr darr darr darr darr darr 2middot t - 6 = 20
Solve the equation
2t - 6 = 20
2t - 6 + 6 = 20 + 6
2t = 26
2t __ 2 = 26 ___
2
t = 13
Six hours ago it was 13 degF in Smalltown
20 -35 = 5 __ 9 ( x - 32 )
-35 = 5 __ 9 x - 160 ____
9
+ 160 ____ 9
______
+ 160 ____ 9
- 155 ____ 9 = 5 __
9 x
thinsp- 155 ____ 9 divide ( 5 __
9 ) = 5 __
9 x divide ( 5 __
9 )
-thinsp 31
155 times 9
1
= x
9 1
times 5
1
- 31 ___ 1 = x
-31 = x
The temperature is -31degF
21 Let a = Artaudrsquos ageopposite of Artaudrsquos age add 40 equals 28
darr darr darr darr darr darr(-) a + 40 = 28
Solve the equation
-a + 40 = 28
-a + 40 - 40 = 28 - 40
-a = -12
-a ___ -1
= -12 ____ -1
a = 12
Artaud is 12 years old
22 Let c = number of customers when Sven startedtwice number of
customers when Sven started
plus 11 more equals present number of customers
darr darr darr darr darr2 middot c +11 = 73
Solve the equation
2c + 11 = 73
2c + 11 - 11 = 73 - 11
2c = 62
2c ___ 2 = 62 ___
2
c = 31
Sven had 31 customers when he started
23 Let p = original price of the jacket
half original less $6 equals amount
price paid
darr darr darr darr darr
1 __ 2
middot p -6 = 88
Solve the equation
1 __ 2 p - 6 = 88
1 __ 2 p - 6 + 6 = 88 + 6
1 __ 2 p = 94
2 sdot 1 __ 2 p = 2 sdot 94
p = 188
The original price was $188
Copyright copy by Houghton Mifflin Harcourt 40 All rights reserved
24 115 minus 8n = 19
Solve the equation for n
115 - 8n = 19
_ -115 _ -115
-8n = -96
-8n _____ -8
= -96 _____ -8
n = 12
They had 19 apples left after 12 days
25 -55x + 056 = -164
-55x + 056 - 056 = -164 - 056
-55x = -22
-55x ______ -22
= -22 _____ -22
x = 04
26 -42x + 315 = -651
-42x + 315 - 315 = -651 - 315
-42x = -966
-42x ______ -42
= -966 ______ -42
x = 23
27 k ___ 52
+ 819 = 472
k ___ 52
+ 819 - 819 = 472 - 819
k ___ 52
= -347
52 sdot k ___ 52
= 52 ( -347 )
k = -18044
28 Sample answer -3x - 5 = -26
29 Sample answer x __ 5 + 10 = 5
30 When dividing both sides by 3 the student forgot to
divide 2 by 3
3x + 2 = 15
3x ___ 3 + 2 __
3 = 15 ___
3
x + 2 __ 3 = 5
- 2 __ 3
___
- 2 __ 3
___
x = 5 - 2 __ 3
x = 5 times3
___ 1
times3 - 2 __
3
x = 15 ___ 3 - 2 __
3
x = 13 ___ 3 or 4 1 __
3
The solution should be x = 4 1 __ 3
31 a 2(x + 40) = 234
Solve the equation for x
2x + 80 = 234
2x + 80 - 80 = 234 - 80
2x = 154
2x ___ 2 = 154 ____
2
x = 77
Trey saved $77
b Sample answer In both solutions you would
divide $234 by 2 then subtract 40 234 divide 2 ndash 40
= 77 These are the same operations applied in
the same order as when solving the equation
Focus on Higher Order Thinking
32 F = 18c + 32
F - 32 = 18c + 32 - 32
F - 32 = 18c
F - 32 ______ 18
= 18c ____ 18
F - 32 ______ 18
= c
33 P = 2 ( ℓ + w ) P = 2ℓ + 2w
P - 2ℓ = 2ℓ - 2ℓ + 2w
P - 2ℓ = 2w
P - 2ℓ ______ 2 = 2w ___
2
P - 2ℓ ______ 2 = w
34 ax + b = c
ax + b - b = c - b
ax = c - b
ax ___ a = c - b ______ a
x = c - b ______ a
MODULE 6
Ready to Go On
1 Add the amounts for the cost of first day of the field
trip with the second day of the field trip where n is
the number of members in the club
15n + 60 + 12n + 95
Therefore the total cost of the two-day field trip can
be written as the expression 27n + 155
2 h + 97 = -97
_ -97 _ -97
h = -194
3 - 3 __ 4 + p = 1 __
2
+ 3 __ 4 + 3 __
4
p = 1 __ 2 + 3 __
4
p = 1 times2
___ 2
times2 + 3 __
4
p = 2 __ 4 + 3 __
4
p = 5 __ 4
4 -15 = -02k
-15 _____ -02
= -02k ______ -02
75 = k
Copyright copy by Houghton Mifflin Harcourt 41 All rights reserved
5 y ___
-3 = 1 __
6
y ___
-3 ( -3 ) = 1 __
6 ( -3 )
y = 1 __ 6 times -3 ___
1
y = -3 ___ 6
y = -1 ___ 2
6 - 2 __ 3
m = -12
- 2 __
3 m _____
- 2 __ 3 = -12 ____
- 2 __ 3
m = -12 divide - 2 __ 3
m = -12 ____ 1 divide - 2 __
3
m = -12 ____ 1 times - 3 __
2
m = -36 ____ -2
m = 18
7 24 = - t ___ 45
24 ( 45 ) = - t ___ 45
( 45 )
108 = -t
-108 = t
8 Let d represent the number of the day after the first
day for example d = 1 means the first day after the
day he started number of number number
2 times day after plus of sit-ups equals of sit-ups
first day first day today
darr darr darr darr darr darr darr
2 middot d + 15 = 33
Equation 2d + 15 = 33
9 5n + 8 = 43
5n + 8 - 8 = 43 - 8
5n = 35
5n ___ 5 = 35 ___
5
n = 7
10 y __
6 - 7 = 4
y __
6 - 7 + 7 = 4 + 7
y __
6 = 11
6 sdot y __
6 = 6 sdot 11
y = 66
11 8w - 15 = 57
8w - 15 + 15 = 57 + 15
8w = 72
8w ___ 8 = 72 ___
8
w = 9
12 g
__ 3 + 11 = 25
g
__ 3 + 11 - 11 = 25 - 11
g
__ 3 = 14
3 sdot g
__ 3 = 3 sdot 14
g = 42
13 f __ 5 - 22 = -25
f __ 5 - 22 + 22 = -25 + 22
f __ 5 = -03
5 sdot f __ 5 = 5 ( -03 )
f = -15
14 - 1 __ 4 (p + 16) = 2
- 1 __ 4 p - 4 = 2
- 1 __ 4 p - 4 + 4 = 2 + 4
- 1 __ 4 p = 6
-4 sdot - 1 __ 4 p = 6 sdot -4
p = -24
15 Sample answer Analyze the situation to determine
how to model it using a two-step equation Solve
the equation Interpret the solution in the given
situation
Copyright copy by Houghton Mifflin Harcourt 42 All rights reserved
MODULE 7 Inequalities
Are You Ready
1 9w = -54
9w ___ 9 = -54 ____
9
w = -6
2 b - 12 = 3
thinsp _ + 12 = _ + 12
b = 15
3 n __ 4
= -11
4 times n __ 4
= 4 ( -11 )
n = -44
4-7
ndash5ndash10 0 5 10
75 4 6
8 3 - (-5)
3 + 5
8
9 -4 - 5
-9
10 6 - 10
-4
11 -5 - (-3)
-5 + 3
-2
12 8 - (-8)
8 + 8
16
13 9 - 5
4
14 -3 - 9
-12
15 0 - (-6)
0 + 6
6
LESSON 71
Your Turn
4 y minus 5 ge minus7
_ +5 _ +5
y ge minus2
-4-5 -3 -2-1 0 1 2 3 4 5
Check Substitute 0 for y
minus1 ge -8
minus1(minus2) le -8(minus2)
2 le 16
5 21 gt 12 + x
_ -12 _ minus12
9 gt x
x lt 9
10 2 3 4 5 6 7 8 9 10
Check Substitute 8 for x
21 gt 12 + 8
21 gt 12 + 8
21 gt 20
6 -10y lt 60
-10y
_____ -10
lt 60 ____ -10
y gt -6
-10-9 -8 -7 -6 -5 -4 -3 -2-1 0 1
Check Substitute -5 for y
-10y lt 60
-10(-5) lt 60
50 lt 60
7 7 ge - t __ 6
7(-6) le - t __ 6 (-6)
-42 le t
t ge -42
-46 -45 -44 -43 -42 -41 -40-47
Check Substitute -36 for t
7 ge - t __ 6
7 ge - ( -36 ____
6 )
7 ge 6
8 Write and solve an inequality
Let m = the number of months
35m le 315
35m ____ 35
le 315 ____ 35
m le 9
Tony can pay for no more than 9 months of his gym
membership using this account
Guided Practice
1 -5 le -2
_ +7 _ +7
2 le 5
2 -6 lt -3
-6 ___ -3
gt -3 ___ -3
2 gt 1
3 7 gt -4
_ -7 _ -7
0 gtthinsp -11
Copyright copy by Houghton Mifflin Harcourt 43 All rights reserved
4 -1 ge -8
-1 ( -2 ) le -8 ( -2 )
2 le 16
5 n - 5 ge -2
_ +5 _ +5
n ge 3
-5 -4 -3 -2-1 0 3 4 51 2
Check Substitute 4 for n
n - 5 ge -2
4 - 5 ge -2
-1 ge -2
6 3 + x lt 7
_ -3 _ -3
x lt 4
-2-1 0 3 4 5 6 7 81 2
Check Substitute 3 for x
3 + x lt 7
3 + 3 lt 7
6 lt 7
7 -7y le 14
-7y
____ -7 ge 14 ___ -7
y ge -2
-5-6-7 -4 -3 -2-1 0 1 2 3
Check Substitute -1 for y
-7y le 14
-7 ( -1 ) le 14
7 le 14
8 b __ 5 gt -1
b __ 5 ( 5 ) gt -1 ( 5 )
b gt -5
-5-6-7-8 -4 -3 -2-1 0 1 2
Check Substitute 0 for b
b __ 5 gt -1
0 __ 5 gt
-1
0 gt -1
9 a -4t ge -80
b -4t ge -80
-4t ____ -4
le -80 ____ -4
t le 20
It will take the physicist 20 or fewer hours to change
the temperature of the metal
c The physicist would have to cool the metal for
more than 20 hours for the temperature of the
metal get cooler than -80deg C
10 You reverse the inequality symbol when you divide
or multiply both sides of an inequality by a negative
number
Independent Practice
11 x - 35 gt 15
_ + 35 _ +35
x gt 50
100 20 30 40 50 60 70 80 90100
Check Substitute 51 for x
x - 35 gt 15
51 minus 35 gt 15
16 gt 15
12 193 + y ge 201
_ -193 _ minus193
y ge 8
10 2 3 4 5 6 7 8 9 10
Check Substitute 9 for y
193 + y ge 201
193 + 9 ge 201
202 ge 201
13 - q
__ 7 ge -1
- q
__ 7 ( -7 ) le -1 ( -7 )
q le 7
8 9 105 6 70 1 2 3 4
Check Substitute ndash14 for q
- q
__ 7 ge -1
- -14 ____ 7 ge
-1
2 ge -1
14 -12x lt 60
-12x _____ -12
gt 60 ____ -12
x gt -5
0-10-9 -8 -7 -6 -5 -4 -3 -2-1
Check Substitute -4 for x
-12x lt 60
-12 ( -4 ) lt 60
48 lt 60
15 5 gt z -3
_ +3 _ +3
8 gt z
z lt 8
10 2 3 4 5 6 7 8 9 10
Check Substitute 7 for z
5 gt z - 3
5 gt 7 - 3
5 gt 4
Copyright copy by Houghton Mifflin Harcourt 44 All rights reserved
16 05 le y __
8
05 ( 8 ) le y __
8 ( 8 )
4 le y
y ge 4
8 9 105 6 70 1 2 3 4
Check Substitute 8 for y
05 le y __
8
05 le 8 __
8
05 le 1
17 Write and solve an inequality
Let x = the number of inches
12 + x le 28
_ -12 _ -12
x le 16
The puppy will grow at most 16 inches more
18 Write and solve an inequality
Let w = the total weight of the kittens
w __ 7 lt 35
w __ 7 ( 7 ) lt 35 ( 7 )
w lt 245
The possible combined weights of the kittens is any
weight less than 245 ounces but greater than 0
19 Write and solve an inequality
Let s = the number of sides
6s le 42
6s ___ 6 le 42 ___
6
s le 7
The length of a side is at most 7 inches
20 Write and solve an inequality
Let x = the amount Tom needs to spend
3025 + x ge 50
_ -3025 _ -3025
x ge 1975
Tom needs to spend at least $1975
21 Write and solve an inequality
Let w = the width of the region
155w ge 1705
155w ______ 155
ge 1705 _____ 155
w ge 11
The possible width of the region is at least 11 feet
22 Write and solve an inequality
Let t = the number of seconds
thinsp-12t lt -120
-12t _____ -12
gt -120 _____ -12
t gt 10
No let t be the number of seconds the descent
takes the inequality is ndash12t lt -120 so t gt 10 so
the submarinersquos descent takes 10 seconds or more
23 Write and solve an inequality
Let s = the amount of spinach
3s le 10
3s ___ 3 le 10 ___
3
s le 3 1 __ 3
The greatest amount of spinach she can buy is 3 1 __ 3
pounds
24 Write and solve an inequality
Let m = the amount of money Gary has
m ___ 05
le 55
m ___ 05
( 05 ) le 55 ( 05 )
m le 275
Gary has at most $275
25 Write and solve an inequality
Let x = the number of pounds of onions
125x le 3
125x _____ 125
le 3 ____ 125
x le 24
No 125x le 3 x le 24 so 24 pounds of onions is
the most Florence can buy 24 lt 25 so she cannot
buy 25 pounds
Focus on Higher Order Thinking
26 If you divide both sides of -7z ge 0 by -7 and do
not reverse the inequality symbol you get z ge 0
This is incorrect because if you choose a value from
the possible solutions such as z = 1 and substitute
it into the original equation you get -7 ge 0 which is
not true
27 x gt 9 for each inequality in each case the number
added to x is 9 less than the number on the right
side of each inequality so x gt 9 is the solution
28 Find the formula for the volume of a rectangular
prism
V = lwh
Write and solve an inequality
Let h = the height in inches
( 13 ) ( 1 __ 2 ) h lt 65
65h lt 65
65h ____ 65
lt 65 ___ 65
h lt 10
All heights greater than 0 in and less than 10 in
( 13 ) ( 1 __ 2 ) h lt 65 65h lt 65 h lt 10 A height cannot
be 0 or less than 0 so h gt 0 and h lt 10
Copyright copy by Houghton Mifflin Harcourt 45 All rights reserved
LESSON 72Your Turn
3 Let a represent the amount each member must
raise
Number of members 45
Starting amount $1240
Target amount $6000
starting number amount each is greater target
amount plus of members times member than or amount
must raise equal to
darr darr darr darr darr darr darr $1240 + 45 middot a ge $6000
Equation 1240 + 45a ge 6000
4 Let n represent the greatest number of rides Ella
can go on
Starting amount $40
Admission price $6
Cost for each ride $3
admission cost for number is less starting
price plus each ride times of rides than or amount
equal to
darr darr darr darr darr darr darr $6 + $3 middot n le $40
Equation 6 + 3n le 40
5 x is the solution of the problem the quantity you
are looking for
3x means that for a reason given in the problem
the quantity you are looking for is multiplied by 3
+ 10 means that for a reason given in the problem
10 is added to 3x
gt 30 means that after multiplying the solution x by
3 and adding 10 to it the result must be greater
than 30
Sample answer An exam consists of one essay
question worth 10 points and several multiple choice
questions worth 3 points each If Petra earns full
points on the essay question how many multiple
choice questions must she get right in order to get
a score greater than 30 points
6 x is the solution of the problem the quantity you are
looking for
5x means that for a reason given in the problem
the quantity you are looking for is multiplied by 5
-50 means that for a reason given in the problem
50 is subtracted from 5x
le 100 means that after multiplying the solution x by
5 and subtracting 50 from it the result must be less
than or equal to 100
Sample answer Miho has $100 to spend on her
garden She spends $50 on gardening supplies
Vegetable plants cost $5 each What is the greatest
number of plants she can buy
Guided Practice
1
- -- -
-
lt
++++++
+ + ++ + +
+
2
---
gt
+ + ++ + +
+ + ++ + +
+ + +
3 Let a represent the amount each member must
raise
Amount to be raised $7000
Amount already raised $1250
Number of members 92 amount number of amount each is greater target
already plus members times member than or amount
raised raises equal to
darr darr darr darr darr darr darr 1250 + 92 times a ge 7000
The inequality that represents this situation is
1250 + 92a ge 7000
4 x is the solution of the problem 7x is the solution
multiplied by 7 -18 means that 18 is subtracted
from 7x le 32 means that the result can be no
greater than 32
5 Sample answer Alexa has $32 to spend on T-shirts
for her friends She has a gift card worth $18 T-shirts
cost $7 each How many T-shirts can Alexa buy
6 Sample answer Choose a variable to represent
what you want to find Decide how the information in
the problem is related to the variable Then write an
inequality
Independent Practice
7 number possible amount is
of times amount each minus for more $200
friends friend earns supplies than
darr darr darr darr darr darr darr 3 middot a - $28 gt $200
3a + 28 gt 200
Let a = possible amount each friend earned
8 cost of number cost of less than amount
bagel times of bagels plus cream or equal Nick
cheese to has
darr darr darr darr darr darr darr $075 middot n + $129 le $700
075n + 129 le 700
Let n = the number of bagels Nick can buy
9 number max amount amount less than total amount
of shirts times each shirt minus of gift or equal Chet can
can cost certificate to spend
darr darr darr darr darr darr darr 4 sdot a - 25 le 75
4a - 25 le 75Let a = the maximum amount each shirt can cost
Copyright copy by Houghton Mifflin Harcourt 46 All rights reserved
10 number of number number of is less total
seats in plus of rows on times seats in than equal number
balcony ground floor one row equal to of people
darr darr darr darr darr darr darr 120 + 32 middot n le 720
120 + 32n le 720
Let n = the number of people in each row
11 amount commission amount greater than earning
earned per plus rate times of sales or equal to for this
month month
darr darr darr darr darr darr darr 2100 + 005 middot s ge 2400
2100 + 005s ge 2400
Let s = the amount of her sales
12 number number average greater
of cans plus of days times number of than goal
collected cans per day
darr darr darr darr darr darr darr 668 + 7 n gt 2000
668 + 7n gt 2000
Let n = the average number of cans collected each
day
13 cost per cost per number of less than total amount
month plus CD times CDs she or equal spent in
buys to a month
darr darr darr darr darr darr darr
$7 + $10 middot c le $100
7 + 10c le 100
Let c = the number of CDs Joanna buys
14 cost of cost for number of less than total amount
belt plus each times shirts he or equal of money
shirt can buy to Lionel has
darr darr darr darr darr darr darr
$22 + $17 middot n le $80
22 + 17n le 80
Let n = the number of shirts he can buy
15 Sample answer Mr Craig is buying pizzas for the
7th grade field day He can spend up to $130 and
needs 15 pizzas He has a $20 coupon How much
can he spend per pizza $10 or less per pizza
16 ldquoat leastrdquo in this case means m ge 25
17 ldquono greater thanrdquo in this case means k le 9
18 ldquoless thanrdquo in this case means p lt 48
19 ldquono more thanrdquo in this case means b le -5
20 ldquoat mostrdquo in this case means h le 56
21 ldquono less thanrdquo in this case means w ge 0
22 The average score of the three tests Marie has
already taken and the three she will still take
is given by
95 + 86 + 89 + 3s
________________ 6
where s is the average score on the three remaining
tests
This value needs to be greater than or equal to 90
so the inequality can be written as
95 + 86 + 89 + 3s
________________ 6 ge 90 or
95 + 86 + 89 + 3s ge 540 or
270 + 3s ge 540
Focus on Higher Order Thinking
23 5 + 10 lt 20 Sample answer If the combined length
of two sides of a triangle is less than the length of
the third side the two shorter sides will not be long
enough to form a triangle with the third side Here
the combined length of 5 ft and 10 ft is 15 ft not
enough to make a triangle
24 -m gt 0 Sample answer Since m is less than 0 it
must be a negative number -m represents the
opposite of m which must be a positive number
since the opposite of a negative number is positive
So -m gt 0
25 n gt 1 __ n if n gt 1
n lt 1 __ n if n lt 1
n = 1 __ n if n = 1
LESSON 73
Your Turn
1 Model the inequality
++
++++
+++
++++
++++
+++
gt
Add seven -1-tiles to both sides of the mat
++
++++
+++
++++
++++
+++
gt
- -- -- --
- -- -- --
Remove zero pairs from both sides of the mat
++
++++
gt
Divide each side into equal groups
++
++++
gt
Copyright copy by Houghton Mifflin Harcourt 47 All rights reserved
The solution is x gt 2
+ + +gt
2 Model the inequality
+++++
----
+++++
+ +++++
ge
Add four +1-tiles to both sides of the mat
+++++
----
+++++
+ ++
++++
+++
++++
ge
Remove zero pairs from the left side of the mat
+++++
+++++
+ +++++
++++
ge
Divide each side into equal groups
+++++
+++++
+ +++++
++++
ge
The solution is h ge 3
+ + + +ge
3 Use inverse operations to solve the inequality
5 - p
__ 6 le 4
5 - 5 - p
__ 6 le 4 - 5
thinsp- p
__ 6 le -1
thinsp-6 ( - p
__ 6 ) ge -6 ( -1 )
p ge 6
Graph the inequality and interpret the circle and
arrow
0 1 4 5 72 3 6 8 9 10
Joshua has to run at a steady pace of at least 6 mih
4 Substitute each value for v in the inequality
3v - 8 gt 22
v = 9 v = 10 v = 11
3 ( 9 ) - 8 gt 22 3 ( 10 ) - 8 gt 22 3 ( 11 ) - 8 gt 22
Evaluate each expression to see if a true inequality
results
3 ( 9 ) - 8 gt 22 3 ( 10 ) - 8 gt
22 3 ( 11 ) - 8 gt
22
27 - 8 gt 22 30 - 8 gt
22 33 - 8 gt
22
19 gt 22 22 gt
22 25 gt
22
not true not true true
v = 11
5 Substitute each value for h in the inequality
5h + 12 le -3
h = -3 h = -4 h = -5
5 ( -3 ) + 12 le -3 5 ( -4 ) + 12 le -3 5 ( -5 ) + 12 le -3
Evaluate each expression to see if a true inequality
results
5 ( -3 ) + 12 le -3 5 ( -4 ) + 12 le
-3 5 ( -5 ) + 12 le
-3
-15 + 12 le -3 -20 + 12 le
-3 -25 + 12 le
-3
-3 le -3 -8 le
-3 -13 le
-3
true true true
h = -3 h = -4 h = -5
Copyright copy by Houghton Mifflin Harcourt 48 All rights reserved
Guided Practice
1 Remove 4 +1-tiles from both sides then divide each
side into 3 equal groups the result is x lt 3
2 Use inverse operations to solve the inequality
5d - 13 lt 32
5d - 13 + 13 lt 32 + 13
5d lt 45
5d ___ 5 lt 45 ___
5
d lt 9
Graph the inequality
20 6 84 10 12 14 16 18 20
3 Use inverse operations to solve the inequality
-4b + 9 le -7
-4b + 9 - 9 le -7 - 9
-4b le -16
-4b ____ -4
ge -16 ____ -4
b ge 4
Graph the inequality
20 6 84 10 12 14 16 18 20
4 Substitute each value for m in the inequality
2m + 18 gt - 4
m = -12 m = -11 m = -10
2 ( -12 ) + 18 gt -4 2 ( -11 ) + 18 gt -4 2 ( -10 ) + 18 gt -4
Evaluate each expression to see if a true inequality
results
2 ( -12 ) + 18 gt -4 2 ( -11 ) + 18 gt
- 4 2 ( -10 ) + 18 gt
- 4
- 24 + 18 gt -4 - 22 + 18 gt
- 4 - 20 + 18 gt
- 4
- 6 gt - 4 - 4 gt
- 4 - 2 gt
- 4
not true not true true
m = -10
5 Substitute each value for y in the inequality
- 6y + 3 ge 0
y = 1 y = 1 __ 2 y = 0
-6 ( 1 ) + 3 ge 0 -6 ( 1 __ 2 ) + 3 ge 0 -6 ( 0 ) + 3 ge 0
Evaluate each expression to see if a true inequality
results
-6 ( 1 ) + 3 ge 0 - 6 ( 1 __
2 ) + 3 ge
0 - 6 ( 0 ) + 3 ge
0
-6 + 3 ge 0 -3 + 3 ge
0 0 + 3 ge
0
-3 ge 0 0 ge
0 3 ge
0
not true true true
y = 1 __ 2
y = 0
6 Solve the inequality
65 - 4t ge 15
65 - 65 - 4t ge 15 - 65
-4t ge -5
-4t ____ -4
le -5 ___ -4
t le 125
Graph the inequality
0 05 1 15 2 25
Lizzy can spend from 0 to 125 h with each student
No 15 h per student will exceed Lizzyrsquos available
time
7 Sample answer Apply inverse operations until you
have isolated the variable If you multiply or divide
both sides of the inequality by a negative number
reverse the direction of the inequality symbol
Independent Practice
8 2s + 5 ge 49
2s + 5 - 5 ge 49 - 5
2s ge 44
2s ___ 2 ge 44 ___
2
s ge 22
10 14 1612 18 20 22 24 26 28 30
9 -3t + 9 ge -21
-3t + 9 - 9 ge -21 -9
-3t ge -30
-3t ____ -3
le -30 ____ -3
t le 10
ndash2ndash4ndash6ndash8ndash10 0 2 4 6 8 10
10 55 gt -7v + 6
55 - 6 gt -7v + 6 - 6
49 gt - 7v
49 ___ -7 lt -7v ____ -7
v gt -7
-10-9 -8 -7 -6 -5 -4 -3 -2 -1 0
11 21 1 __ 3 gt 3m - 2 2 __
3
21 1 __ 3 + 2 2 __
3 gt 3m - 2 2 __
3 + 2 2 __
3
24 gt 3m
24 ___ 3 gt 3m ___
3
8 gt m or m lt 8
0 1 4 5 72 3 6 8 9 10
12 a ___ -8
+ 15 gt 23
a ___ -8
+ 15 - 15 gt 23 - 15
a ___ -8
gt 8
-8 ( a ___ -8
) lt -8 ( 8 )
a lt -64
-70 -68 -66 -64 -62 -60
Copyright copy by Houghton Mifflin Harcourt 49 All rights reserved
13 f __ 2 - 22 lt 48
f __ 2 - 22 + 22 lt 48 + 22
f __ 2 lt 70
2 ( f __ 2 ) lt 2 ( 70 )
f lt 140
100 110 120 130 140 150
14 -25 + t __ 2 ge 50
-25 + 25 + t __ 2 ge 50 + 25
t __ 2 ge 75
2 ( t __ 2 ) ge 2 ( 75 )
t ge 150
130 140 150 160 170 180
15 10 + g ___
-9 gt 12
10 - 10 + g ___
-9 gt 12 - 10
g ___
-9 gt 2
-9 ( g ___
-9 ) lt -9 ( 2 )
g lt -18
-20 -18 -14 -12 -10-16
16 252 le -15y + 12
252 - 12 le -15y + 12 - 12
24 le - 15y
24 ____ -15
ge -15y
_____ -15
y le -16
-20 -18 -14 -12 -10-16
17 -36 ge -03a + 12
-36 - 12 ge -03a + 12 - 12
-48 ge -03a
-48 _____ -03
le -03a ______ -03
a ge 16
10 11 12 13 14 16 17 18 19 2015
18 80 - 2w ge 50
80 - 80 - 2w ge 50 - 80
- 2w ge -30
-2w ____ -2
le -30 ____ -2
w le 15
The width is a positive number no greater than
15 inches the possible widths in inches will be 10
11 12 13 14 and 15
19 Inequality 7n - 25 ge 65
7n - 25 ge 65
7n - 25 + 25 ge 65 + 25
7n ge 90
7n ___ 7 ge 90 ___
7
n ge 12 6 __ 7
Grace must wash at least 13 cars because n must
be a whole number
Focus on Higher Order Thinking
20 No Sample answer If x lt x - 1 then subtracting
x from both sides of the inequality 0 lt -1 That is
untrue so no value of x can be less than x - 1
21 a
10 3 42 5 6 7 8 9 10
b
10 3 42 5 6 7 8 9 10
c A number cannot simultaneously be less than 2
and greater than 7 Therefore there is no number
that satisfies both inequalities
d Consider the graph of x gt 2 and x lt 7
The solution includes all the numbers on the
number line so the solution set is all numbers
22 Sample answer Joseph might have reasoned that n
was first multiplied by 2 then increased by 5 to give
a result less than 13 Working backward he would
have subtracted 5 from 13 ( to get 8 ) then divided by
2 ( to get 4 ) giving n lt 4 Shawnee would have
followed these same steps but would have used a
variable and invers operations
MODULE 7
Ready to Go On
1 n + 7 lt -3
thinsp _ -7
_ -7
n lt -10
2 5p ge -30
5p
___ 5 ge -30 ____
5
p ge -6
3 14 lt k + 11
_ -11 _ -11
3 lt k
4 d ___ -3
le minus6
( -3 ) ( d ) ge ( -3 ) ( -6 )
d ge 18
Copyright copy by Houghton Mifflin Harcourt 50 All rights reserved
5 c - 25 le 25
_ +25 _ +25
c le 5
6 12 ge -3b
12 ___ -3
le -3b _____ -3
-4 le b
7 Let n be the number of minimum points Jose must
score 562 + n ge 650
Solve the inequality
562 + n ge 650
_ -562 _ -562
n ge 88
8 Let t be the number of minutes Lainey can descend
-20 - 20t ge -100
9 2s + 3 gt 15
_ -3 _ -3
2s gt 12
2s ___ 2
gt 12 ___ 2
s gt 6
10 - d ___ 12
- 6 lt 1
_ +6 _ +6
- d ___ 12
lt 7
12 ( - d ___ 12
) lt 12 ( 7 )
-d lt 84
d gt -84
11 -6w - 18 ge 36
_ +18 _ +18
thinsp-6w ge 54
-6w _____ -6
le 54 ___ -6
w le -9
12 z __ 4 + 22 le 38
_ -22 _ -22
z __ 4 le 16
4 ( z __ 4 ) le 4 ( 16 )
z le 64
13 b __ 9 - 34 lt -36
_ +34 _ +34
b __ 9 lt -2
9 ( b __ 9 ) lt 9 ( -2 )
b lt -18
14 -2p + 12 gt 8
-12 ____
-12 ____
-2p gt -4
-2p
____ -2 lt -4 ___
-2
p lt 2
15 Sample answer Look for key words or phrases
that indicate inequality such as ldquogreater thanrdquo
ldquoless thanrdquo ldquoat mostrdquo or ldquoat leastrdquo
Copyright copy by Houghton Mifflin Harcourt 51 All rights reserved
MODULE 8 Modeling Geometric Figures
Are You Ready
1 3x + 4 = 10
3x + 4 - 4 =10 - 4
3x = 6
3x ___ 3 = 6 __
3
x = 2
2 5x - 11 = 34
5x - 11 + 11 = 34 + 11
5x = 45
5x ___ 5 = 45 ___
5
x = 9
3 -2x + 5 = -9
-2x + 5 - 5 = -9 - 5
-2x = -14
-2x ____ -2
= -14 ____ -2
x = 7
4 -11 = 8x + 13
-11 - 13 = 8x + 13 - 13
-24 = 8x
-24 ____ 8 = 8x ___
8
-3 = x
5 4x - 7 = -27
4x - 7 + 7 = -27 + 7
4x = -20
4x ___ 4 = -20 ____
4
x = -5
6 1 __ 2 x + 16 = 39
1 __ 2 x + 16 - 16 = 39 - 16
1 __ 2 x = 23
( 2 ) 1 __ 2 x = ( 2 ) 23
x = 46
7 12 = 2x - 16
12 + 16 = 2x - 16 + 16
28 = 2x
28 ___ 2 = 2x ___
2
14 = x
8 5x - 15 = -65
5x - 15 + 15 = -65 + 15
5x = -50
5x ___ 5 = -50 ____
5
x = -10
9 x __ 5 = 18 ___
30
x times 30 = 5 times 18
30x = 90
30x ____ 30
= 90 ___ 30
x = 3
10 x ___ 12
= 24 ___ 36
x times 36 = 12 times 24
36x = 288
36x ____ 36
= 288 ____ 36
x = 8
11 3 __ 9 = x __
3
3 times 3 = 9 times x
9 = 9x
9 __ 9 = 9x ___
9
1 = x
12 14 ___ 15
= x ___ 75
14 times 75 = 15 times x
1050 = 15x
1050 _____ 15
= 15x ____ 15
70 = x
13 8 __ x = 14 ___ 7
8 times 7 = x times 14
56 = 14x
56 ___ 14
= 14x ____ 14
4 = x
14 14 ___ x = 2 __ 5
14 times 5 = x times 2
70 = 2x
70 ___ 2 = 2x ___
2
35 = x
15 5 __ 6 = x ___
15
5 times 15 = 6 times x
75 = 6x
75 ___ 6 = 6x ___
6
125 = x
Solutions KeyGeometry
UNIT
4
Copyright copy by Houghton Mifflin Harcourt 52 All rights reserved
16 81 ___ 33
= x ____ 55
81 times 55 = 33 times x
4455 = 33x
4455 _____ 33
= 33x ____ 33
135 = x
LESSON 81
Your Turn
6 Length 132 in times 5 ft ____ 3 in
= 22 ft
Width 6 in times 5 ft ____ 3 in
= 10 ft
Area 10 ft ( 22 ft ) = 220 square feet
Guided Practice
1
Blueprint
length (in)3 6 9 12 15 18
Actual
length (ft)5 10 15 20 25 30
a The wall is 30 feet long
b 25 ft times 3 in ____ 5 ft
= 15 in
2 The width is 7 in times 4 ft ____ 2 in
= 14 ft and the length is
14 in times 4 ft ____ 2 in
= 28 ft and the area is
28 ft ( 14 ft ) = 392 square feet
3 Length 10 cm times 5 m _____ 2 cm
= 25 m
Width 6 cm times 5 m _____ 2 cm
= 15 m
Area 25 m ( 15 m ) = 375 square meters
4 a
b Length is 36 m and width is 24 m using both
scales
5 If the scale drawing is complete and accurate you
can use it to find any length or area of the object of
the drawing
Independent Practice
6 a 2 in times 40 cm ______ 1 in
= 80 cm
15 in times 40 cm ______ 1 in
= 60 cm
The dimensions of the painting are 80 cm by 60 cm
b 80 cm times 60 cm = 4800 c m 2
c 80 cm times 1 in _______ 254 cm
asymp 315 in
60 cm times 1 in _______ 254 cm
asymp 236 in
The dimensions of the painting are approximately
315 in by 236 in
d 315 in times 236 in asymp 743 i n 2
7 120 ft times 1 unit _____ 5 ft
= 24 units
75 ft times 1 unit _____ 5 ft
= 15 units
The dimensions of the drawing are 24 units by
15 units
8 Sample answer 2 in6 ft 1 in3 ft and 1 in1 yd
9 Because the scale is 10 cm1 mm and because
10 cm is longer than 1 mm the drawing will be
larger
10 a Let r represent the scale
54 ft times r = 810 m
r = 810 m ______ 54 ft
r = 150 m ______ 1 ft
The scale is 1 ft = 150 m
b 54 ft times 12 in _____ 1 ft
= 648 in
Let b represent the number of tiny bricks
b = 648 in times 1 brick ______ 04 in
b = 162 bricks
The model is 162 tiny bricks tall
11 a Let h represent the height of the model
h = 30 ft times 126 cm _______ 1 ft
h = 378 cm
Let n represent the number of toothpicks
n = 378 cm times 1 toothpick
_________ 63 cm
n = 6 toothpicks
The model will be 6 toothpicks tall
b 378 cm times 1 swab ______ 76 cm
asymp 5 swabs
The model will be about 5 cotton swabs tall
Focus on Higher Order Thinking
12 If the area of the scale drawing is 100 square cm
then one side is 10 cm Let s represent the side
length of the actual floor
s = 10 cm times 2 ft _____ 1 cm
s = 20 ft
So the area is 20 ft(20 ft) = 400 ft 2
The ratio of areas is 100 square cm 400 square feet
or 1 square cm 4 square feet
Copyright copy by Houghton Mifflin Harcourt 53 All rights reserved
13 Decide on the new scale yoursquod like to use Then find
the ratio between the old scale and the new scale
and redraw the scale drawing accordingly For
example the ratio could be 13 In that case you
would redraw the dimensions at three times the
original size
14 Sample answer 1 __ 4 in 8 ft 40 ft by 24 feet 960 f t
2
LESSON 82
Guided Practice
1 The two angles 45deg and a right angle or 90deg with
the included side 8 cm determine the point at which
the sides meet so a unique triangle is formed
2 The sum of the measures of the two short sides
4 + 3 = 7 The sum is less than the measure of the
long side 11 so no triangle is formed
3 The two angles 40deg and 30deg with the included side
7 cm determine the point at which the sides meet
so a unique triangle is formed
4 The sum of the measures of the two short sides
6 + 7 = 13 The sum is greater than the measure of
the long side 12 so a unique triangle is formed
5 Sample answer Segments with lengths of 5 in
5 in and 100 in could not be used to form a
triangle
Independent Practice
6 A figure with side lengths of 3 centimeters and 6
centimeters and an included angle of 120deg deter-
mine the length of the third side of a triangle and so
produce a unique triangle
6 cm
3 cm120˚
7 The side lengths proposed are 15 ft 21 ft and 37 ft
The sum of the measures of the two shorter sides
15 + 21 = 36 So the sum is less than the measure
of the long side 37 No such triangle can be created
8 The three angle measures can be used to form
more than one triangle The sign and the scale
drawing are two different-sized triangles with the
same angle measures
Focus on Higher Order Thinking
9 More than one triangle can be formed Two triangles
can be created by connecting the top of the 2-in
segment with the dashed line once in each spot
where the arc intersects the dashed line The
triangles are different but both have side lengths of
2 in and 1 1 __ 2 in and a 45deg angle not included
between them
10 The third side has a length of 15 in The third side
must be congruent to one of the other two sides
because the triangle is isosceles The third side
cannot measure 6 in because 6 + 6 is not greater
than 15 So the third side must measure 15 in
LESSON 83
Guided Practice
1 triangle or equilateral triangle
2 rectangle
3 triangle
4 rainbow-shaped curve
5 Sample answer Draw the figure and the plane
Independent Practice
6 Sample answer A horizontal plane results in cross
section that is a circle A plane slanted between
horizontal and vertical results in an oval cross
section A vertical plane through the cylinder results
in a rectangle A vertical plane along an edge of the
cylinder results in a line cross section
7 You would see circles or ovals with a cone but not
with a pyramid or prism
Focus on Higher Order Thinking
8 The plane would pass through the cube on a
diagonal from the top to the bottom of the cube
9 a It is a circle with a radius of 12 in
b The cross sections will still be circles but their
radii will decrease as the plane moves away from
the spherersquos center
10 The dimensions of two faces are 12 in by 8 in two
are 8 in by 5 in and two are 12 in by 5 in the
volume is 480 in 3
11 Sample answer If you think of a building shaped like
a rectangular prism you can think of horizontal
planes slicing the prism to form the different floors
Copyright copy by Houghton Mifflin Harcourt 54 All rights reserved
LESSON 84
Your Turn
5 Supplementary angles sum to 180deg Sample answer angFGA and angAGC
6 Vertical angles are opposite angles formed by two
intersecting lines
Sample answer angFGE and angBGC
7 Adjacent angles are angles that share a vertex and
one side but do not overlap Sample answer
mangFGD and mangDGC
8 Complementary angles are two angles whose
measures have a sum of 90deg Sample answer
mangBGC and mangCGD
9 Because mangFGE = 35deg and angFGE and angBGC are
vertical angles that means mangBGC = 35deg also
Because lines _
BE and _
AD intersect at right angles
mangBGD = 90deg so mangBGC + mangCGD = 90deg which means
mangBGC + mangCGD = 90deg 35deg + x = 90deg 35deg minus 35deg + x = 90deg minus 35deg x = 55deg
mangCGD = 55deg
10 angJML and angLMN are supplementary so their
measures sum to 180deg mangJML + mangLMN = 180deg 3x + 54deg = 180deg 3x + 54deg - 54deg = 180deg - 54deg 3x = 126deg
3x ___ 3 = 126deg ____
3
x = 42deg
mangJML = 3x = 3 ( 42deg ) = 126deg
11 Sample answer You can stop at the solution step
where you find the value of 3x because the measure
of angJML is equal to 3x
Guided Practice
1 angUWV and angUWZ are complementary angles
2 angUWV and angVWX are adjacent angles
3 angAGB and angDGE are vertical angles
so mangDGE = 30deg
4 mangCGD + mangDGE + mangEGF = 180deg 50deg + 30deg + 2x = 180deg 80deg + 2x = 180deg 2x = 100deg mangEFG = 2x = 100deg
5 mangMNQ + mangQNP = 90deg 3x - 13deg + 58deg = 90deg so 3x + 45deg = 90degThen 3x = 45deg and x = 15deg mangMNQ = 3x - 13deg = 3 ( 15deg ) - 13deg = 45deg - 13deg = 32deg
6 Sample answer Let mangS = x Write and solve an
equation ( x + 3x = 180deg ) to find x then multiply the
value by 3
Independent Practice
7 Sample answer angSUR and angQUR are adjacent
They share a vertex and a side
8 Sample answer angSUR and angQUP
9 Sample answer angTUS and angQUN
10 mangQUR = 139deg Sample answer angSUR and angSUP
are supplementary so mangSUP = 180deg - 41deg = 139deg angSUP and angQUR are vertical angles so they are
congruent and mangQUR = mangSUP = 139deg
11 mangRUQ is greater Sample answer angSUR and
angNUR are complementary so
mangNUR = 90deg - 41deg = 49deg mangTUR = 41deg + 90deg which is less than
mangRUQ = 49deg + 90deg
12 Because angKMI and angHMG are vertical angles their
measures are equal
mangKMI = mangHMG
84 = 4x
84 ___ 4 = 4x ___
4
x = 21deg
13 Because angKMH and angKMI are supplementary
angles the sum of their measures is 180deg mangKMH + mangKMI = 180deg x + 84 = 180
x + 84 - 84 = 180 - 84
x = 96
mangKMH = 96deg
14 Because angCBE and angEBF are supplementary
angles the sum of their measures is 180deg mangCBE + mangEBF = 180deg x + 62 = 180
x + 62 - 62 = 180 - 62
x = 118
mangCBE = 118deg
15 Because angABF and angFBE are complementary
angles the sum of their measures is 90deg mangABF + mangFBE = 90deg x + 62 = 90
x + 62 - 62 = 90 - 62
x = 28
mangABF = 28deg
16 Because angCBA and angABF are supplementary
angles the sum of their measures is 180deg mangABF = 28deg so
mangCBA + mangABF = 180deg x + 28 = 180 - 28
x + 28 - 28 = 152
mangCBA = 152deg
Copyright copy by Houghton Mifflin Harcourt 55 All rights reserved
17 If the two angles are complementary the sum of
their angles is 90degmangA + mangB = 90deg ( x + 4deg ) + x = 90deg 2x + 4deg = 90deg _ -4deg _ -4deg 2x = 86deg
2x ___ 2 = 86deg ___
2
x = 43degBecause x = mangB then mangB = 43deg and
mangA = 43deg + 4deg so mangA = 47deg
18 If the two angles are supplementary the sum of their
angles is 180degmangD + mangE = 180deg 5x + x = 180deg 6x = 180deg
6x ___ 6 = 180deg ____
6
x = 30degBecause x = mangE then mangE = 30deg and
mangD = 30deg x 5 so mangD = 150deg
19 If the two angles are complementary the sum of
their angles is 90deg When angles are divided into
minutes and seconds one apostrophe signifies a
minute and two apostrophes signifies a second
mangJ + mangK = 90deg0000
48deg268+ mangK = 90deg0000
_ -48deg268 _ -48deg268
mangK = 41deg3352
mangK = 41deg3352 or mangK = 41 degrees
33 minutes 52 seconds
Focus on Higher Order Thinking
20 Yes a parking lot can be built because the measure
of angle K is 180deg - ( 50deg + 90deg ) or 40deg which is
greater than 38deg
21 Disagree the sum of the measures of a pair of
complementary angles is 90deg So the measure of
each angle must be less than 90deg 119deg gt 90deg
22 a The sum of mangA and its complement will be 90deg Let x represent the complement
mangA + x = 90deg 77deg + x = 90deg _ -77deg = _ -77deg x = 13deg The complement of mangA has a measure of 13deg
and a complement of a complement of mangA
would have an angle equal to mangA or 77deg b A complement of a complement of an angle has
the same measure of the angle itself Let xdeg be
the measure of an angle The measure of a
complement of the angle is ( 90 - xdeg ) A complement of that angle has a measure of
( 90 - ( 90 - xdeg ) ) = ( 90 - 90 + xdeg ) = xdeg
MODULE 8
Ready to Go On
1
Living
roomKitchen Office Bedroom Bedroom Bathroom
Actual
ℓ times w ( ft ) 16 times 20 12 times 12 8 times 12 20 times 12 12 times 12 6 times 8
Blueprint
ℓ times w ( in ) 4 times 5 3 times 3 2 times 3 5 times 3 3 times 3 15 times 2
2 No The side lengths proposed are 8 cm 4 cm and
12 cm The sum of the measures of the two shorter
sides 4 + 8 = 12 So no such triangle can be
created
3 The longest side could be 15 cm because 20 cm is
too long given the lengths of the other sides
4 A circle is a possible cross section of a sphere
A point is another
5 A circle rectangle oval and line are possible cross
sections of a cylinder
6 mangBGC and mangFGE are vertical angles so
mangFGE = 50deg
7 If the two angles are complementary the sum of
their angles is 90deg mangS + mangY = 90deg
( 2 ( mangY ) - 30deg ) + mangY = 90deg 3 ( mangY ) - 30deg = 90deg _ +30deg = _ +30deg 3 ( mangY ) = 120deg
3 ( mangY ) ________ 3 = 120deg ____
3
mangY = 40deg
mangY = 40deg
8 Sample answer You can use scale drawings to plan
rooms or gardens
Copyright copy by Houghton Mifflin Harcourt 56 All rights reserved
MODULE 9 Circumference Area and Volume
Are You Ready
1 416
_ times 13
1248
_ +thinsp4160
5408
5408
2 647
_ times thinsp04
2588
2588
3 705
_ times thinsp94
2820
_ +thinsp63450
66270
6627
4 256
_ timesthinsp049
2304
_ +thinsp10240
12544
12544
5 1 __ 2 ( 14 ) ( 10 )
7 ( 10 )
70 i n 2
6 ( 35 ) ( 35 )
1225 ft 2
7 ( 8 1 __ 2 ) ( 6 )
17 ___ 1 2 sdot 6 3 __
1
51 i n 2
8 1 __ 2 ( 125 ) ( 24 )
1 __ 2 ( 24 ) ( 125 )
( 12 ) ( 125 )
15 m 2
LESSON 91
Your Turn
3 d = 11 cm
C = πd
C asymp 314 ( 11 )
C asymp 3454
The circumference is about 3454 cm
6 C = πd
44 asymp 314d
44 ____ 314
asymp d
d asymp 1401 yards
Divide the diameter of the garden by the digging
rate
1401 divide 7 = 2001
It takes Lars about 2 hours to dig across the garden
Guided Practice
1 d = 9 in
C asymp 314 ( 9 )
C asymp 2826 in
2 r = 7 cm
C = 2πr
C asymp 2 ( 22 ___ 7 ) ( 7 )
C asymp 44 cm
3 d = 25 m
C = πd
C asymp 314 ( 25 )
C asymp 785 m
4 r = 48 yd
C = 2πr
C asymp 2 ( 314 ) ( 48 )
C asymp 3014 yd
5 r = 75 in
C = 2πr
C asymp 2 ( 314 ) ( 75 )
C asymp 471 in
6 Find the diameter
C = πd
66 asymp 314d
66 ____ 314
asymp 314d _____ 314
21 asymp d
Find the cost
Carlos needs 21 + 4 = 25 feet of rope
25 times $045 = $1125
Carlos will pay $1125 for the rope
7 Because C = π yd and C = πd d = 1 yd then
r = 05 yd
d = 1 yd
8 Because C = 788 ft and C = 2πr
2πr = 788
2πr ___ 2π
= 788 ____ 2π
r asymp 788 _______ 2 ( 314 )
r asymp 1255 ft
d = 2r asymp 2 ( 1255 ft )
d asymp 2510 ft
9 d = 2r so r = d __ 2 asymp 34 ___
2
r asymp 17 in
C = πd asymp 314 ( 34 )
C = 1068 in
Copyright copy by Houghton Mifflin Harcourt 57 All rights reserved
10 Use the formula C = πd and substitute
314 for π and 13 for the diameter
Independent Practice
11 d = 59 ft
C = πd
C asymp 314 ( 59 )
C asymp 1853 ft
12 r = 56 cm
C = 2πr
C asymp 2 ( 22 ___ 7 ) ( 56 )
C asymp 352 cm
13 d = 35 in
C = πd
C asymp ( 22 ___ 7 ) ( 35 )
C asymp 110 in
14 Sample answer In exercises 12 and 13 the radius
or diameter is a multiple of 7
15 r = 94 ft
d = 2r = 2 ( 94 )
d = 188 ft
C = πd
C asymp 314 ( 188 )
C asymp 590 ft
16 d = 475 in
r = d __ 2 = 475 ____
2
r = 2375 in
C = πd
C asymp 314 ( 475 )
C asymp 14915 in
17 d = 18 in
r = d __ 2 = 18 ___
2
r = 9 in
C = πd
C asymp 314 ( 18 )
C asymp 5652 in
18 r = 15 ft
C = 2πr
C asymp 2 ( 314 ) ( 15 ) = 942 ft
The cost for edging is C times $075 per foot
so ( 942 ) ( 075 ) = 7065 or about $707
19 C = πd
C asymp ( 22 ___ 7 ) ( 63 )
C asymp 198 ft
The distance traveled is 12 times the
circumference of the Ferris wheel so
distance = 12 ( 198 ) or about 2376 ft
20 C = πd asymp 314 ( 2 )
C asymp 628 ft
Converting km to ft
2 km sdot ( 3280 ft _______
1 km ) = 6560 ft
6560 ft
_______ 628 ft
= 104459
The wheel makes about 1045 revolutions
21 The distance your friend walks is half the
circumference of the pond
1 __ 2 C = 1 __
2 πd asymp 1 __
2 sdot 314 ( 025 ) = 03925
Your friend walks approximately 03925 mi
The difference is 03925 - 025 = 01425
Your friend walks about 014 mi farther
22 Capitol Rotunda Dimensions
Height 180 ft
Circumference 3015 ft
Radius r = C ___ 2π asymp 3015
_______ 2 ( 314 )
asymp 48 ft
Diameter d = 2r = 2 ( 48 ) = 96 ft
Focus on Higher Order Thinking
23 The length of the fence is half the circumference
plus the diameter
1 __ 2 C = 1 __
2 πd asymp 1 __
2 sdot 314 ( 30 ) = 471
The total distance is 471 + 30 = 771 ft
The total cost is the length of fence times the cost
per linear foot
( 771 ft ) ( $925 _____
ft ) = $71318
It will cost about $71318
24 The circumference of the patio is
C = πd asymp 314 ( 18 ) = 5652 ft
Converting the length of one strand of lights from
inches to feet
( 54 in ) ( 1 ft _____ 12 in
) = 45 ft
To find the number of strands of lights divide the
circumference by the length of one strand
5652 ft _______ 45 ft
= 1256
Because Sam cannot buy a fraction of a strand he
must buy 13 strands
25 The distance is the difference in the circumferences
C inner
= πd asymp 314 ( 150 ) = 471 ft
The outer diameter is 150 ft + 2 ( 2 ft ) = 154 ft
C outer
= πd asymp 314 ( 154 ) = 48356 ft
The difference is 48356 - 471 = 1256 ft
It is about 1256 ft farther
26 No The circumference of the larger gear is about
πd asymp 314 ( 4 ) = 1256 inches The circumference of
the smaller gear is about πd asymp 314 ( 2 ) = 628
inches So the circumference of the larger gear is
628 inches more than the circumference of the
smaller gear
Copyright copy by Houghton Mifflin Harcourt 58 All rights reserved
27 Pool B about 057 m or 184 ft Sample answer
24 feet asymp 732 m so the diameter of Pool B is
greater and the circumference is greater
314 ( 75 ) - 314 ( 732 ) = 314 ( 018 ) asymp 057
057 m asymp 187 ft
LESSON 92
Your Turn
4 A = π r 2 A = π ( 10 ) 2
A asymp 314 ( 10 ) 2
A asymp 314 sdot 100
A asymp 314 f t 2
Guided Practice
1 r = d __ 2 = 14 ___
2 = 7 m
A = π r 2 A = π ( 7 ) 2
A asymp 314 ( 7 ) 2
A asymp 314 sdot 49
A asymp 1539 m 2
2 A = π r 2 A = π ( 12 ) 2
A asymp 314 ( 12 ) 2
A asymp 314 sdot 144
A asymp 4522 m m 2
3 r = d __ 2 = 20 ___
2 = 10 yd
A = π r 2 A = π ( 10 ) 2
A asymp 314 ( 10 ) 2
A asymp 314 sdot 100
A asymp 314 y d 2
4 A = π r 2 A = π ( 8 ) 2
A asymp 314 ( 8 ) 2
A asymp 314 sdot 64
A asymp 20096 i n 2
5 r = d __ 2 = 12 ___
2 = 6 cm
A = π r 2 A = π ( 6 ) 2
A asymp 314 ( 6 ) 2
A asymp 314 sdot 36
A asymp 11304 c m 2
6 r = d __ 2 = 13 ___
2 = 65 in
A = π r 2 A = π ( 65 ) 2
A asymp 314 ( 65 ) 2
A asymp 314 sdot 4225
A asymp 13267 i n 2
7 C = 4π = 2πr
4π ___ 2π
= 2πr ___ 2π
r = 2
A = π r 2 A = π ( 2 ) 2
A = 4π square units
8 C = 12π = 2πr
12π ____ 2π
= 2πr ___ 2π
r = 6
A = π r 2 A = π ( 6 ) 2
A = 36π square units
9 C = π __ 2 = 2πr
π __ 2 divide 2π = 2πr ___
2π
π __ 2 sdot 1 ___
2π = r
1 __ 4 = r
A = π r 2
A = π ( 1 __ 4 ) 2 = π ( 1 ___
16 )
A = π ___ 16
square units
10 A = π r 2 = 64π
π r 2 ___ π = 64π ____ π
r 2 = 64
r = 8
C = 2πr
= 2π ( 8 )
=16π yd
11 A = π r 2
Independent Practice
12 r = d __ 2 = 10 ___
2 = 5 in
A = π r 2 A = π ( 5 ) 2
A asymp 314 ( 5 ) 2
A asymp 314 sdot 25
A asymp 785 i n 2
13 A = π r 2 A = π ( 16 ) 2
A asymp 314 ( 16 ) 2
A asymp 314 sdot 256
A asymp 80384 c m 2
14 The area of the window is half the area of a circle of
diameter 36 in
r = d __ 2 = 36 ___
2 = 18 in
A semicircle
= 1 __ 2 π r 2
A semicircle
= 1 __ 2 π ( 18 ) 2
A semicircle
asymp 1 __ 2 ( 314 ) ( 18 ) 2
A semicircle
asymp 05 sdot 314 sdot 324
A asymp 50868 i n 2
Copyright copy by Houghton Mifflin Harcourt 59 All rights reserved
15 If the point ( 3 0 ) lies on the circle and the origin is
its center the radius of the circle is 3 units
A = π r 2 A = π ( 3 ) 2
A asymp 314 ( 3 ) 2
A asymp 314 sdot 9A asymp 2826 square units
16 The difference in areas is given by
A r = 75 mi
- A r = 50 mi
π ( 75 ) 2 - π ( 50 ) 2
= π ( 7 5 2 minus 5 0 2 ) = π ( 5625 minus 2500 ) = π ( 3125 ) asymp 98125
The area of the relayed signal is about 9813 mi 2
greater
17 The area of the field which is not reached by the
sprinkler is the area of the field minus the area
reached by the sprinkler or s 2 minus π r 2 where
s = 12 m and r is the radius of the circular area The
diameter of the circle is equal to a side of the field
12 m so the radius is 12 ___ 2 = 6 m So
s 2 minus π r 2 = 1 2 2 minus π ( 6 ) 2
= 144 minus π ( 36 )
asymp 144 minus 11304 = 3096
The area not reached by the sprinkler is
approximately 3096 m 2
18 No the area of the regular pancake is 4π in 2 and the
area of the silver dollar pancake is π in 2 so the area
of the regular pancake is 4 times the area of the
silver dollar pancake
19 No the top of the large cake has an area 9 times
that of the small cake The area of the top of the
large cake is 144π in 2 and that of the small cake is
16π in 2
20 Sample answer First find the radius of the circle by
using the formula C = 2πr Then substitute the
radius into the formula for the area of a circle
21 The 18-inch pizza is a better deal because it costs
about $20
_____ π ( 9 ) 2
asymp $008 or 8 cents per square inch
while the 12-inch pizza costs about $10
_____ π ( 6 ) 2
asymp $009
or 9 cents per square inch
22 a Because the bear can walk at a rate of 2 miles
per hour and was last seen 4 hours ago the
radius of the area where the bear could be found
is given by ( 2 miles per hour ) ( 4 hours ) = 8 miles
A = π r 2 = π ( 8 ) 2
= π ( 64 )
asymp 20096
The searchers must cover an area of about
201 mi 2
b The additional area is the difference in areas of
circles with radii ( 2 miles per hour ) ( 5 hours )
= 10 miles and the original 8 miles
A new
minus A old
= π ( 10 ) 2 - π ( 8 ) 2
= π ( 1 0 2 - 8 2 ) = π ( 100 - 64 )
= π ( 36 ) asymp 11304
The searchers would have to cover about 113 mi 2
more area
Focus on Higher Order Thinking
23 No the combined area is 2π r 2 while the area of a
circle with twice the radius is 4π r 2
24 The area is multiplied by a factor of n 2
25 To find the part that is the bullrsquos-eye take the ratio of
the area of the bullrsquos-eye to that of the whole target
The radius of the bullrsquos-eye is 3 __ 2 = 15 in and
the radius of the whole target is 15 ___ 2 = 75 in
A
bullrsquos-eye ________
A whole target
=
π ( 15 ) 2 ______
π ( 75 ) 2
= ( 15 ) 2
_____ ( 75 ) 2
= 225 _____ 5625
= 004
The bullrsquos-eye is 004 or 4 of the whole target
LESSON 93
Your Turn
2 The figure can be separated into a rectangle and
two right triangles
The dimensions of the large rectangle are
length = 8 + 3 = 11 ft width = 4 ft
The dimensions of the two small triangles are
base = 3 ft height = 2 ft ( upper triangle ) base = 3 ft height = 3 ft ( lower triangle ) The area of the rectangle is
A = ℓw = 11 sdot 4 = 44 f t 2
The area of the upper triangle is
A = 1 __ 2 bh = 1 __
2 sdot 3 sdot 2 = 3 f t 2
The area of the lower triangle is
A = 1 __ 2 bh = 1 __
2 sdot 3 sdot 3 = 45 f t 2
Therefore the total area of the figure is
44 + 3 + 45 = 515 f t 2
3 The figure can be separated into a square and a
semicircle
Each side of the square is equal to 10 m
The radius of the semicircle is half the diameter
or 10 ___ 2 = 5 m
The area of the square is
A = s 2 = 1 0 2 = 100 m 2
The area of the semicircle is
A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 5 ) 2
A asymp 1 __ 2 sdot 314 sdot 25
A asymp 3925 m 2
Therefore the approximate total area of the figure is
100 + 3925 = 13925 m 2
Copyright copy by Houghton Mifflin Harcourt 60 All rights reserved
4 The composite figure is made up of a rectangle and two
semicircles which can be combined to form one circle
The dimensions of the rectangle are
length = 5 ft width = 4 ft
The diameter of the circle is 4 ft so the radius is
4 __ 2 = 2 ft
The area of the rectangle is
A = ℓw = 5 sdot 4 = 20 f t 2
The area of the circle is
A = π r 2 A asymp 314 sdot ( 2 ) 2
A asymp 314 sdot 4A asymp 1256 f t 2
The approximate total area is the sum of these
two areas
20 + 1256 = 3256 f t 2
Because the glass costs $28 per square foot
multiply the total area by the cost per square foot
( 3256 f t 2 ) ( $28 ____
f t 2 ) = $91168
It will cost about $91168 to replace the glass
Guided Practice
1 Separate the figure into a triangle a rectangle and
a parallelogram
Find the area of each figure
For triangle A = 1 __ 2 bh = 1 __
2 ( 4 ) ( 2 ) = 4
For rectangle A = ℓw = ( 5 ) ( 3 ) = 15
For parallelogram A = bh = ( 5 ) ( 3 ) = 15
Triangle 4 cm 2 rectangle 15 cm
2 parallelogram
15 cm 2
Step 3 Find the area of the composite figure
4 + 15 + 15 = 34 cm 2
The area of the irregular shape is 34 cm 2
2 Method 1
A 1 = ℓw A
2 = ℓw
= 12 sdot 9 = 20 sdot 9 = 108 = 180
Total area = 288 c m 2
Method 2
A 1 = ℓw A
2 = ℓw
= 9 sdot 8 = 12 sdot 8 = 72 = 216
Total area = 288 c m 2
3 Separate the figure into a trapezoid with h = 5 ft
b 1 = 7 ft and b 2 = 4 ft and a parallelogram with
base = 4 ft and height = 4 ft
For trapezoid A = 1 __ 2 h ( b
1 + b
2 )
A = 1 __ 2 ( 5 ) ( 7 + 4 )
A = 1 __ 2 ( 5 ) ( 11 ) = 275 f t 2
For parallelogram A = bh = ( 4 ) ( 4 ) = 16 f t 2
Find the area of the composite figure
275 + 16 = 435 ft 2
Multiply the total area by the cost per square foot to
find the cost
( 435 f t 2 ) ( $225 _____
f t 2 ) = $9788
4 The first step is separating the composite figure into
simpler figures
Independent Practice
5 Area of square A = s 2 = 2 6 2 = 676 i n 2
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 13 ) 2
A asymp 1 __ 2 sdot 314 sdot 169
A asymp 26533 i n 2
The approximate total area is the sum
676 + 26533 = 94133 in 2
6 a The floor of the closet is a composite of a
rectangle with length = 10 ft and width = 4 ft and
a triangle with base = 6 ft and height = 3 + 4 = 7 ft
Area of rectangle A = ℓw = 10 sdot 4 = 40 f t 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 6 sdot 7
A = 1 __ 2 sdot 42
A = 21 f t 2
The total area is the sum
40 + 21 = 61 f t 2
b The cost is the area multiplied by the cost per
square foot
( 61 f t 2 ) ( $250 _____
f t 2 ) = $15250
7
O 42-2-4
2
-4
y
A (-2 4) B (0 4)
C (2 1)D (5 1)
E (5 -2)F (-2 -2)
The area can be thought of as a composite of a
trapezoid and a rectangle
For trapezoid Let b 1 of the trapezoid be the
segment from the point ( -2 1 ) point C with length
4 units b 2 be from point A to point B with length
2 units and height equal to 3 units
For rectangle The corners of the rectangle are
( -2 1 ) D E and F Let the length of the rectangle
be 7 units and the width be 3 units
Area of trapezoid
A = 1 __ 2 h ( b
1 + b
2 )
A = 1 __ 2 ( 3 ) ( 4 + 2 )
A = 1 __ 2 ( 3 ) ( 6 ) = 9 square units
Copyright copy by Houghton Mifflin Harcourt 61 All rights reserved
Area of rectangle A = ℓw
A = 7 sdot 3 A = 21 square units
The total area is the sum
9 + 21 = 30 square units
8 The field is a composite of a square with side = 8 m
a triangle with base = 8 m and height = 8 m and a
quarter of a circle with radius = 8 m
Area of square A = s 2 = 8 2 = 64 m 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 8 sdot 8
A = 1 __ 2 sdot 64
A = 32 m 2
Area of quarter circle A = 1 __ 4 π r 2
A asymp 1 __ 4 sdot 314 sdot ( 8 ) 2
A asymp 1 __ 4 sdot 314 sdot 64
A asymp 5024 f t 2
The approximate total area is the sum
64 + 32 + 5024 = 14624 m 2
9 The bookmark is a composite of a rectangle with
length = 12 cm and width = 4 cm and two
semicircles which combine to form a full circle with
diameter = 4 cm so radius = 4 __ 2 = 2 cm
Area of rectangle A = ℓw = 12 sdot 4 = 48 c m 2
Area of circle A = π r 2 A asymp 314 sdot ( 2 ) 2
A asymp 314 sdot 4 A asymp 1256 c m 2
The approximate total area is the sum
48 + 1256 = 6056 cm 2
10 The pennant is a composite of a rectangle with
length = 3 ft and width = 1 ft and a triangle with
base = 1 ft and height = 1 ft
Area of rectangle A = ℓw = 3 sdot 1 = 3 f t 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 1 sdot 1
A = 1 __ 2 sdot 1
A = 05 f t 2
The area of one pennant is the sum
3 + 05 = 35 ft 2
Alex is making 12 pennants so the total area of all
12 pennants is 12 sdot 35 = 42 ft 2
The cost for the pennants will be the total area times
the fabric cost per square foot
( 42 f t 2 ) ( $125 _____
f t 2 ) = $5250
11 The area of the square is the total area minus the
area of triangle
325 ft 2 - 75 ft 2 = 25 ft 2
The area of a square is A = s 2 so s 2 = 25 f t 2
Because 5 sdot 5 = 25 the length of each side of the
square is 5 ft
Focus on Higher Order Thinking
12 The area of the garden can be found from counting
squares there are 18 full squares and 4 half-squares
for a total of 20 square units Each square unit will
grow about 15 carrots So Christina will grow about
20 ( 15 ) or 300 carrots
13 To find the length of the three sides of the square
subtract the lengths of the two sides of the triangle
from the perimeter The total length of three sides of
the square is 56 - 20 = 36 in Divide by 3 to find
that the length of one side and the base of the
triangle is equal to 12 in The total area of the figure
is the area of the square plus the area of the
triangle
Area of square A = s 2 = 1 2 2 = 144 i n 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 12 sdot 8
A = 1 __ 2 sdot 96
A = 48 i n 2
The total area is the sum
144 + 48 = 192 in 2
14 Think of the scarf as a rectangle minus two
semicircles The rectangle has length = 28 in and
width = 15 in The circle has diameter = 15 in so
its radius is 15 ___ 2 = 75 in
Area of rectangle A = ℓw = 28 sdot 15 = 420 i n 2
Area of circle A = π r 2 A asymp 314 sdot ( 75 ) 2
A asymp 314 sdot 5625
A asymp 176625 i n 2
The total area is the difference
420 - 176625 = 243375 in 2 or 243 3 __
8 i n 2
15 a The window is a composite of a square and a
semicircle Because each square in the window
has an area of 100 in 2 the length of each side is
10 in So each side of the square portion of the
entire window has length 10 sdot 4 = 40 in The
diameter of the semicircle is also 40 in so
the radius is 40 ___ 2 = 20 in
Area of square A = s 2 = 4 0 2 = 1600 i n 2
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 20 ) 2
A asymp 1 __ 2 sdot 314 sdot 400
A asymp 628 i n 2
The approximate total area is the sum
1600 + 628 = 2228 in 2
Copyright copy by Houghton Mifflin Harcourt 62 All rights reserved
b The shade is a composite of a rectangle and
a semicircle The length of the rectangle is equal
to the length of one side of the square portion
of the window plus 2 sdot 4 inches for a total of
40 + 2 sdot 4 = 48 in
The height of the rectangular portion of the shade
is equal to 4 times the length of one side of the
square portion of the window plus 4 inches for a
total of 40 + 4 = 44 in
The diameter of the semicircle at the top is the
same as the length of the bottom of the shade
48 in so the radius = 48 ___ 2 = 24 in
Area of rectangle A = ℓw = 48 sdot 44 = 2112 i n 2
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 24 ) 2
A asymp 1 __ 2 sdot 314 sdot 576
A asymp 90432 i n 2
The approximate total area of the shade is
the sum
2112 + 90432 asymp 3016 in 2
LESSON 94
Your Turn
3 Find the area of a base
B = l times w
= 9 times 2
= 18 square inches
Find the perimeter of the base
P = 2 ( 9 ) + 2 ( 2 )
= 18 + 4 = 22 inches
Find the surface area
S = Ph + 2B
S = 22 ( 1 1 __ 2 ) + 2 ( 18 )
= 33 + 36
= 69
The surface area of the box is 69 square inches
4 Find the area of the base of the larger prism
B = times w
= 12 times 12
= 144 square inches
Find the perimeter of the base
P = 4 ( 12 )
= 48 inches
Find the surface area of the larger prism
S = Ph + 2B
S = 48 ( 12 ) + 2 ( 144 )
= 576 + 288
= 864 square inches
Find the area of the base of the smaller prism
B = l times w
= 8 times 8
= 64 square inches
Find the perimeter of the base
P = 4 ( 8 )
= 32 inches
Find the surface area of the smaller prism
S = Ph + 2B
S = 32 ( 8 ) + 2 ( 64 )
= 256 + 128
= 384 square inches
Add the surface areas of the two prisms and
subtract the areas not stained (the bottom of the
larger prism and the smaller prism and an equal
area of the top of the larger prism where the smaller
prism sits) Surface area = 864 + 384 - 144 - 64
- 64 = 976 The surface area of the part of the plant
stand that she will stain is 976 square inches
Guided Practice
1 Perimeter of base = 5 + 5 + 8 = 18
Perimeter of base = 18 ft
Height = 7 ft
Base area = 1 __ 2 ( 3 ) ( 8 ) = 12 ft 2
Surface area
S = ( 18 ft ) ( 7 ft ) + 2 ( 12 ft 2 ) = 150 ft 2
2 Find the area of a base of the cube
B = l times w
= 25 times 25
= 625 m 2
Find the perimeter of the base of the cube
P = 4 ( 25 )
= 10 m
Find the surface area of the cube
S = Ph + 2B
S = 10 ( 25 ) + 2 ( 625 )
= 25 + 125
= 375
Surface area of cube
S = 375 m 2
Find the area of a base of the rectangular prism
B = l times w
= 11 times 9
= 99 m 2
Find the perimeter of the base of the rectangular
prism
P = 2 ( 11 ) + 2 ( 9 )
= 22 + 18
= 40 m
Find the surface area of the rectangular prism
S = Ph + 2B
S = 40 ( 7 ) + 2 ( 99 )
= 280 + 198
= 478
Surface area of rectangular prism
S = 478 m 2
Find the overlapping area the bottom of the cube
A = ( 25 ) ( 25 ) = 625
Overlapping area A = 625 m 2
Surface area of composite figure
= 375 + 478 -2 ( 625 ) = 503 m 2
3 Find the surface area of each of the prisms that
make up the solid Add the surface areas and
subtract the areas of any parts that are not on the
surface
Copyright copy by Houghton Mifflin Harcourt 63 All rights reserved
Independent Practice
4 Find the area of a base
B = l times w
= 10 times 3
= 30 in 2
Find the perimeter of the base
P = 2 ( 10 ) + 2 ( 3 )
= 20 + 6
= 26 in
Find the surface area
S = Ph + 2B
S = 26 ( 4 ) + 2 ( 30 )
=104 + 60
= 164 in 2
She needs 164 in 2 of wrapping paper
5 Find the area of the base
B = l times w
= 20 times 15
= 300 cm 2
Find the perimeter of the base
P = 2 ( 20 ) + 2 ( 15 )
= 40 + 30
= 70 cm
Find the surface area of the box
S = Ph + 2B
S = 70 ( 9 ) + 2 ( 300 )
= 630 + 600
= 1230 cm 2
Find the surface area of the top and sides
1230 - 300 = 930 cm 2
Find the area of a glass tile
Area of tile = 5 times 5 = 25 mm 2
Convert cm 2 to mm
2
930 cm 2 times 100 mm
2 ________
1 cm 2 = 93000 mm
2
Find the number of tiles needed
93000 divide 25 = 3720
3720 tiles are needed
6 Find the area of the L-shaped base
Area of L-shape = 2 times 1 + 3 times 1
= 2 + 3 = 5 in 2
Find the perimeter of the L-shaped base
Perimeter = 3 + 3 + 1 + 2 + 2 + 1
= 12 in
Find the surface area
S = Ph + 2B
S = 12 ( 3 ) + 2 ( 5 )
= 36 + 10
= 46 in 2
The surface area of each brace is 46 in 2
7 Find the area of the triangular prism
Perimeter = 25 + 25 + 3 = 8 ft
Base area = 1 __ 2 ( 2 ) ( 3 ) = 3 ft 2
Surface area = Ph + 2B
= 8 ( 4 ) + 2 ( 3 )
= 32 + 6 = 38 ft 2
Find the area of the rectangular prism
Perimeter = 2 ( 3 ) + 2 ( 4 ) = 14 ft
Base area = 3 times 4 = 12 ft 2
Surface area = Ph + 2B
= 14 ( 2 ) + 2 ( 12 )
= 28 + 24 = 52 ft 2
Add the surface areas of the two prisms and
subtract the parts not on the surface
Surface area = 38 + 52 - 12 - 12 = 66 ft 2
The total surface area of the doghouse is 66 ft 2
8 Treat the figure as ( 1 ) a composite of two triangular
prisms and one rectangular prism or ( 2 ) a prism
with a base that is a trapezoid
9 Find the area of the trapezoid base
Area of trapezoid = 1 __ 2 ( b
1 + b
2 ) h
1 __ 2 ( 16 + 48 ) 12 = 384 in
2
Find the perimeter of the base
P = 48 + 20 + 16 + 20 = 104 in
Find the surface area
S = Ph + 2B
S = 104 ( 24 ) + 2 ( 384 )
= 2496 + 768
= 3264 in 2
The surface area of the ramp is 3264 in 2
10 Find the area of the base of the larger prism
B = l times w
= 7 times l
= 7 ft 2
Find the perimeter of the base
P = 2 ( 7 ) + 2 ( 1 )
= 14 + 2
= 16 ft
Find the surface area of the larger prism
S = Ph + 2B
S = 16 ( 2 ) + 2 ( 7 )
= 32 + 14
= 46 f t 2
Find the area of the base of the smaller prism
B = l times w
= 1 times 1
= 1 ft 2
Find the perimeter of the base
P = 2 ( 1 ) + 2 ( 1 )
= 2 + 2 = 4 ft
Find the surface area of the smaller prism
S = Ph + 2B
S = 4 ( 3 ) + 2 ( 1 )
= 12 + 2
= 14 ft 2
Add the surface areas of the two prisms and
subtract the parts not on the surface
Surface area = 46 + 14 - 1 - 1 = 58 ft 2
The surface area of the stand is 58 ft 2
11 Find the number of cans of paint needed
58 divide 25 = 232
It takes 2 full cans and 1 partial can so 3 cans are
needed
Find the cost of 3 cans of paint
3 times 679 = 2037
No they need 3 cans which will cost $2037
Copyright copy by Houghton Mifflin Harcourt 64 All rights reserved
12 Find the area of the base of the box
B = l times w
= 27 times 24
= 648 cm 2
Find the perimeter of the base
P = 2 ( 27 ) + 2 ( 24 )
= 54 + 48
= 102 cm
Find the surface area of the box
S = Ph + 2B
S = 102 ( 10 ) + 2 ( 648 )
= 1020 + 1296
= 2316 cm 2
2316 cm 2 will be covered with paper
13 Area of the original base B = l times w
Area of the new base = 2l times 2w = 4lw = 4B
Perimeter of the original = 2l + 2w
Perimeter of the new = 2 ( 2l ) + 2 ( 2w ) =
2 ( 2l + 2w ) = 2P
Original S = Ph + 2B
New S = 2Ph + 2 ( 4B )
No Ph doubles and 2B quadruples S more than
doubles
Focus on Higher Order Thinking
14 Find the area of the base of the prism
B = l times w
= 25 times 25
= 625 ft 2
Find the perimeter of the base
P = 4 ( 25 )
= 10 ft
Find the surface area of the prism
S = Ph + 2B
S = 10 ( 35 ) + 2 ( 625 )
= 35 + 135
= 485 ft 2
Find the surface area less the area of the bottom
surface of the prism
485 - 625 = 4225 ft 2
Find what percent of the surface area less the area
of the bottom is compare to the total surface area
4225 _____ 485
times 100 asymp 87
Sample answer She would be painting about 87
of the total surface area so she will use about 87
of the total amount of paint
15
Circumference ofcircle πd = πtimes4
r = 2 in
9 in
Find the area of the circle base
A = πr 2
asymp 31 4 ( 2 ) 2 = 1256 in 2
Find the circumference of the circle
C = πd
asymp 314 ( 4 ) = 1256 in 2
Find the area of the rectangle
Area asymp 9 times 1256 = 11304 in 2
Find the surface area of the cylinder
S = Ch + 2B
asymp 1256 ( 9 ) + 2 ( 1256 ) = 13816 in 2
Round to the nearest tenth 1382 in 2
The surface area of the oatmeal box is
approximately 1382 in 2
Find the amount of cardboard for 1500 boxes
1500 times 1382 = 207300 in 2
Convert square inches to square feet and round to
the nearest whole number
( 207300 in 2 ) 1 ft 2 _______
144 in 2 asymp 1440 ft 2
It would take about 1440 ft 2 of cardboard
16 Each face has 9 squares 1 cm by 1 cm so S =
54 cm 2 The surface area stays the same when one
or more corner cubes are removed ( Fig 2 3 ) because the number of faces showing is still the
same In Fig 4 S increases because 2 more faces
show
LESSON 95
Your Turn
2 Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 24 ) 7
= 84 m 2
Find the volume of the prism
V = Bh
= ( 84 ) ( 22 )
= 1848 m 3
The volume of the prism is 1848 m 3
5 Find the base area B of the trapezoidal prism
B = 1 __ 2 ( b 1 + b 2 ) h
= 1 __ 2 ( 8 + 12 ) 10
= 1 __ 2 ( 20 ) 10 = 100 cm
2
Find the volume of the prism
V = Bh
= ( 100 ) ( 22 )
= 2200 cm 3
The volume of the prism is 2200 cm 3
7 Find the volume of each prism
Find the base area B of the rectangular prism
B = bh
= ( 13 ) 13
= 169 in 2
Find the volume of the rectangular prism
V = Bh
= ( 169 ) ( 30 )
= 5070 in 3
Copyright copy by Houghton Mifflin Harcourt 65 All rights reserved
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 9 ) 13
= 585 in 2
Find the volume of the triangular prism
V = Bh
= ( 585 ) ( 30 )
= 1755 in 3
Find the sum of the volumes
5070 + 1755 = 6825 in 3
The volume of the composite figure is 6825 in 3
Guided Practice
1 B = 1 __ 2 bh = 1 __
2 ( 8 ) ( 3 ) = 12 ft 2
V = Bh = ( 12 times 7 ) ft 3 = 84 ft 3
2 B = 1 __ 2 ( b 1 + b 2 ) h = 1 __
2 ( 15 + 5 ) 3 = 30 m
2
V = Bh = ( 30 times 11 ) m 3 = 330 m 3
3 Find the base area B of the rectangular prism
B = bh
= ( 4 ) 6 = 24 ft 2
Find the volume of the rectangular prism
V = Bh
= ( 24 ) ( 12 ) = 288 ft 3
The volume of the rectangular prism = 288 ft 3
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 6 ) 4 = 12 ft 2
Find the volume of the triangular prism
V = Bh
= ( 12 ) ( 6 ) = 72 ft 3
The volume of the triangular prism = 72 ft 3
Find the sum of the volumes
288 + 72 = 360 ft 3
The volume of the composite figure = 360 ft 3
4 Find the base area B of the rectangular prism
B = bh
= ( 40 ) ( 50 ) = 2000 ft 2
Find the volume of the rectangular prism
V = Bh
= ( 2000 ) ( 15 ) = 30000 ft 3
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 40 ) ( 10 ) = 200 ft 2
Find the volume of the triangular prism
V = Bh
= ( 200 ) ( 50 ) = 10000 ft 3
Find the sum of the volumes
30000 + 10000 = 40000 ft 3
The volume of the barn is 40000 ft 3
5 Find the base area B of the trapezoidal prism
B = 1 __ 2 ( b 1 + b 2 ) h
= 1 __ 2 ( 10 + 12 ) 5
= 1 __ 2 ( 22 ) 5 = 55 cm
2
Find the volume of the trapezoidal prism
V = Bh
= ( 55 ) ( 7 ) = 385 cm 3
The volume of the container is 385 cm 3
6 Find the volume of each prism using the formula
V = Bh Then add the volumes of all the prisms
Independent Practice
7 The area of the base of the prism is given 35 in 2
Find the volume of the prism
V = Bh
= ( 35 ) ( 5 ) = 175 in 3
The volume of the trap is 175 in 3
8 The shape of the ramp is triangular prism
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 7 ) ( 6 ) = 21 in
2
Find the volume of the triangular prism
V = Bh
= ( 75 ) ( 7 ) = 525 in 3
The volume of the ramp is 525 in 3
9 Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 8 ) ( 4 ) = 16 ft 2
Find the volume of the triangular prism
V = Bh
= ( 16 ) ( 24 ) = 384 ft 3
The space contained within the goal is 384 ft 3
10 Find the base area B of the trapezoidal prism
B = 1 __ 2 ( b 1 + b 2 ) h
= 1 __ 2 ( 7 + 5 ) 4
= 1 __ 2 ( 12 ) 4 = 24 in
2
Find the volume of the trapezoidal prism
V = Bh
= ( 24 ) ( 8 ) = 192 in 3
The volume of the gift box is 192 in 3
11 Find the volume of the triangular prism
V = Bh
= ( 20 ) ( 15 ) = 300 in 3
The units for volume are incorrect the volume is
300 cubic inches
12 The area of the base of the hexagonal prism is
given B = 234 in 3
Find the volume of the hexagonal prism
V = Bh
= ( 234 ) ( 3 ) = 702 in 3
Copyright copy by Houghton Mifflin Harcourt 66 All rights reserved
Find the base area B of the rectangular prism
B = bh
= ( 3 ) ( 3 ) = 9 in 2
Find the volume of the rectangular prism
V = Bh
= ( 9 ) ( 3 ) = 27 in 3
Find the sum of the volumes
702 + 27 = 972 in 3
The volume of the figure is 972 in 3
13 Find the base area B of the larger rectangular prism
B = bh
= ( 75 ) 375 = 28125 m 2
Find the volume of the larger rectangular prism
V = Bh
= ( 28125 ) ( 75 ) asymp 21094 cm 3
Find the base area B of the smaller rectangular
prism
Find the measure of the base
15 - 75 = 75
Find the base area B of the larger rectangular prism
B = bh
= ( 75 ) 375 = 28125 m 2
Find the volume of the smaller rectangular prism
V = Bh
= ( 28125 ) ( 375 ) asymp 10547 cm 3
Find the sum of the volumes of the prisms
21094 + 10547 = 31641 m 3
The volume of the figure rounded to the nearest
hundredth is 31641 m 3
14 Find the volume of the hexagonal candle
V = Bh
= ( 21 ) ( 8 ) = 168 cm 3
Find the amount of wax Josie would have after
making the hexagonal candle
260 - 168 = 92 cm 3
Find the volume of the triangular candle
V = Bh
= ( 7 ) ( 14 ) = 98 cm 3
Find the amount of wax Josie would have after
making the hexagonal candle
260 - 168 = 92 cm 3
Find the area of the base of a triangular candle with
a height of 14 cm
V = Bh
92 = B ( 14 )
92 ___ 14
= B ( 14 ) _____ 14
6 8 ___ 14
= B asymp 657
No the area of the base of the triangular candle
must be less than or equal to about 657 cm 2
15 The base of trapezoidal prism is given 36 in 2 Find
the volume of the trapezoidal prism
V = Bh
= ( 36 ) ( 5 ) = 180 in 3
The base of triangular prism is given 32 in 2
Find the volume of the trapezoidal
prism V = Bh
= ( 32 ) ( 6 ) = 192 in 3
Triangular prism you get 192 in 3 for the same price
you would pay for 180 in 3 with the trapezoidal prism
Focus on Higher Order Thinking
16 Find the area of the base of the trapezoidal prism
V = Bh
286 = B ( 8 )
286 ____ 8 = B ( 8 )
3575 = B
Find the missing dimension of the base of the
trapezoidal prism
1 __ 2 ( 2 + b 2 ) 13 = 3575
1 __ 2 ( 2 + b 2 ) ( 13 ___
13 ) = 3575 _____
13
( 2 ) 1 __ 2 ( 2 + b 2 ) = ( 2 ) 275
2 + b 2 = 55
_ -2 _ -2
b 2 = 35 ft
The missing dimension is 35 ft
17 Find the area of the base of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 10 ) 6 = 30 cm
2
Find the volume of the triangular prism
V = Bh
= ( 30 ) ( 25 ) = 75 cm 3
Find the mass of the doorstop
mass asymp ( V in cm 3 ) ( 86 g
_____ cm
3 )
asymp ( 75 cm 3 ) ( 86 g
_____ cm
3 ) = 645 g
The volume of the doorstop is 75 cm 3 The mass is
about 645 g
18 If both the base and height of the triangular base are
tripled the area of the base is multiplied by 9
Tripling the height of the prism as well means the
volume of the prism is multiplied by 27
19 Use the formula for the volume of a trapezoidal
prism to find a set of dimensions that have a volume
of 120 cm 3
V = Bh
V = [ 1 __ 2 ( b 1 + b 2 ) h 1 ] h 2
120 ≟ [ 1 __ 2 ( 2 + 6 ) 4 ] 75
= [ 1 __ 2 ( 8 ) 4 ] 75
= [ 16 ] ( 75 ) = 120
Try another set of dimensions in the formula
V = Bh
V = [ 1 __ 2 ( b 1 + b 2 ) h 1 ] h 2
120 ≟ [ 1 __ 2 ( 1 + 7 ) 25 ] 12
= [ 1 __ 2 ( 8 ) 25 ] 12
= [ 10 ] 12 = 120
Copyright copy by Houghton Mifflin Harcourt 67 All rights reserved
Sample answers ( 1 ) height of trapezoid = 4 cm
base lengths = 2 cm and 6 cm height of prism
= 75 cm ( 2 ) height of trapezoid = 25 cm base
lengths = 1 cm and 7 cm height of prism = 12 cm
MODULE 9
Ready to Go On
1 r = 7 m A = π r 2 C = 2πr A asymp 314 sdot ( 7 ) 2
C asymp 2 sdot 314 sdot 7 A asymp 314 sdot 49
C asymp 4396 m A asymp 15386 m 2
2 d = 12 cm d = 6 cm so r = 12 ___ 2 = 6 ft
C = πd A = π r 2 C asymp 314 ( 12 ) A asymp 314 sdot ( 6 ) 2
C asymp 3768 cm A asymp 314 sdot 36
A asymp 11304 ft 2
3 The figure is a composite of a semicircle with
diameter = 16 m so radius is 16 ___ 2 = 8m and a
triangle with base = 16 m and height = 10 m
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 8 ) 2
A asymp 1 __ 2 sdot 314 sdot 64
A asymp 10048 m 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 16 sdot 10
A = 1 __ 2 sdot 160
A = 80 m 2
The total area is the sum
80 + 10048 = 18048 m 2
4 The figure is a composite of a parallelogram with
base = 20 cm and height = 45 cm and a rectangle
with length = 20 cm and height = 55 cm
Area of parallelogram A = bh
A = 20 sdot 45
A = 90 c m 2
Area of rectangle
A = ℓw = 20 sdot 55 = 110 c m 2
The total area is the sum
90 + 110 = 200 cm 2
5 Find the area of the triangular base
Area of triangle = 1 __ 2 bh
1 __ 2 ( 4 ) 3 = 6 cm 2
Find the perimeter of the base
P = 3 + 4 + 5 = 12 cm
Find the surface area
S = Ph + 2B
S = 12 ( 10 ) + 2 ( 6 )
thinsp=120 + 12
thinsp= 132 cm 2
Find the volume of the prism
V = Bh
= ( 6 ) 10
= 60 cm 3
6 Find the area of the composite base formed by a
rectangle and a triangle
Area of triangle = 1 __ 2 bh
1 __ 2 ( 4 ) 15 = 3 yd 2
Area of rectangle = bh
( 4 ) 2 = 8 yd 2
Area of the composite base 3 + 8 = 11 yd 2
Find the perimeter of the composite base
P = 4 + 2 + 25 + 25 + 2 = 13 yd
Find the surface area
S = Ph + 2B
S = 13 ( 25 ) + 2 ( 11 )
thinsp= 325 + 22
thinsp= 545 yd 2
The area of the base of the pentagonal prism
is given
B = 234 yd 3
Find the volume of the prism
V = Bh
= ( 11 ) 25
= 275 yd 3
7 Sample answer You can use a composite figure to
model a room then find surface area to decide how
much paint you need to paint the room
Copyright copy by Houghton Mifflin Harcourt 68 All rights reserved
Solutions KeyStatistics
unit
5MODULE 10 Random Samples and Populations
Are You Ready
1 x ___16
=45___40
40x=720
40x ____40
=720____40
x=18
2 x __5=1__
4
4x=5
4x ___4
=5__4
x=5__4=125
3 25___10
=x ___10
125=10x
125____10
=10x ____10
125=x
4 x __6
=2__9
9x= 12
9x ___9
=12___9
x=12___9=4__
3
5 4748495152575960range=60-47=13
6 4566689121213range=13-4=9
7 95979799100106108115range=115-95=20
8 121319273539476671range=71-12=59
9 mean=3+5+7+3+6+4+8+6+9+5_________________________________10
=56
10 mean=81+94+113+67+62+75____________________________6
=82
LESSON 101
Your Turn
4 Yeseveryemployeehadanequalchanceofbeingselected
5 Thequestionisbiasedsincecatsaresuggested
6 ThequestionisnotbiasedItdoesnotleadpeopletopickaparticularseason
Guided Practice
1 Method1ASampleanswer
Random Sample of Seventh Grade Male Students
Student Shoe SizeArturo 75
Jimmy 80
Darnell 90
Ping 75
Zach 85
Jamar 80
BSampleanswer
75+80+90+75+85+80___________________________6
=485____6
asymp81
Meanasymp81
Method2ASampleanswer
Student Shoe Size Student Shoe SizeReggie 85 Ling 85
Stan 80 Marcus 90
Alejandro 90 Tio 85
BSampleanswer
85+80+90+85+90+85____________________________6
=515____6 =86
Mean=size86
2Method1producesresultsthataremorerepresentativeoftheentirestudentpopulationbecauseitisarandomsample
3 Method2producesresultsthatarelessrepresentativeoftheentirestudentpopulationbecauseitisabiasedsample
4 YesSampleanswerWhatisyourfavoritecolor
5 Selectarandomsampleofsufficientsizethatrepresentsthepopulationandaskeachparticipantunbiasedquestions
Independent Practice
6 SampleanswerPaulrsquossamplewasbiasedMaybehisfriendsstudiedmorethanothers
7 SampleanswerNancyrsquossampledidnotincludeasmanystationsThereportcouldincludestationsnationwide
8 ItisabiasedsampleStudentswhoarenrsquotontheteamwonrsquotbeselected
CopyrightcopybyHoughtonMifflinHarcourt 69 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U5M10indd 69 103113 216 AM
9 Itisbiasedbecausestudentswhoarenrsquotinthatclasswonrsquotbeselected
10 Itisarandomsamplebecauseallseventhgradershaveanequalchanceofbeingselected
11 Itisarandomsamplebecausetheorganizationselectsnamesatrandomfromallregisteredvoters
12 Itisbiasedbecausebasketballismentioned
13 Jaersquosquestionisnotbiasedsinceitdoesnotsuggestatypeofarttostudents
Focus on Higher Order Thinking
14 CollinrsquosmethodbetterrepresentstheentirestudentpopulationbecauseheusedarandomsampleKarlrsquosmethodpickedpeoplethatcouldallbefriendsthatgotofootballgamestogetherThesamplemaynotbestrepresenttheentirestudentpopulation
15 a Every10thstudentoutof600meansthatBarbarasurveyed60studentsThiswasarandomsample
b 35___60
= x ____100
xasymp58
Thepercentis58____100
=58
ItappearsreasonablebecauseBarbarausedarandomsampleandsurveyedasignificantpercentofthestudents
16 CarloiscorrectTherearemanyvalidwaystoselectarepresentativesamplefromapopulation
LESSON 102
Your Turn
5 damagedMP3sinsample
______________________sizeofsample
=damagedMP3sinpopulation
________________________sizeofpopulation
6___50
= x_____3500
6sdot70______50sdot70
= x _____3500
420_____3500
= x_____3500
x=420420damagedMP3s
Guided Practice
1
6 7 8 9 10 11 12 13 14 1550 1 2 3 4
2 Orderthedatafindtheleastandgreatestvaluesthemedianandthelowerandupperquartiles
6 7 7 107 114 4 54
Leastvalue
4
Lower quartile
4
Median
65
Upper quartile
7
Greatestvalue11
Drawaboxplot
10 1550
3 Themostcommonagesofchildrenthatusethelibraryare4and7
4 Therangeofagesofchildrenthatusethelibraryisfrom4to11
5 Themedianageofchildrenthatusethelibraryis65
6 defectivephonesinsample
______________________sizeofsample
=defectivephonesinpopulation
_________________________sizeofpopulation
4___60
= x_____4200
4sdot70______60sdot70
= x_____4200
280_____4200
= x_____4200
x=280About280smartphonesintheorderarelikelytobedefective
7 infectedelkinsample
__________________sizeofsample
=infectedelkinpopulation
____________________sizeofpopulation
8___50
= x_____4500
8sdot90______50sdot90
= x_____4500
720_____4500
= x_____4500
x=720About720elkarelikelytobeinfected
8 YoucansetupproportionsusinginformationobtainedinarandomsampleofthepopulationForinstancethenumberofdefectivepartsinabatchcanbeusedtopredicthowmanypartswillbedefectiveinadifferent-sizebatch
divide060
divide060
CopyrightcopybyHoughtonMifflinHarcourt 70 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U5M10indd 70 103113 218 AM
Independent Practice
9 number of people with mispriced item in sample
_______________________________________ size of sample
=
number of people with mispriced item in one day
_______________________________________ size of population
4 ___ 50
= x ____ 600
4 sdot 12 ______ 50 sdot 12
= x ____ 600
48 ____ 600
= x ____ 600
x = 48
About 48 people are likely to have a mispriced item
10 number of boxes with at least one broken crayon in sample
_______________________________________________ size of sample
=
total number of boxes with at least one broken crayon
___________________________________________ size of population
2 ___ 20
= x ____ 130
2 sdot 65 _______ 20 sdot 65
= x ____ 130
13 ____ 130
= x ____ 130
x = 13
About 13 boxes will have at least one broken crayon
11 number of puppies
________________ size of sample
= total number of puppies
___________________ size of population
12 ___ 60
= x _____ 1200
12 sdot 20 ______ 60 sdot 20
= x _____ 1200
240 _____ 1200
= x _____ 1200
x = 240
About 240 puppies are in all of the cityrsquos animal
shelters
12 number of hawks building nests
__________________________ size of sample
= total number of hawks
__________________ size of population
12 ___ 72
= x ______ 10800
12 sdot 150 _______ 72 sdot 150
= x ______ 10800
1800
______ 10800
= x ______ 10800
x = 1800
About 1800 hawks are building nests
13 Yes this seems reasonable because 23 + 27
_______ 2 = 25
is the median of the data
14 Order the data
11 12 12 12 13 13 13 14 14 14 15 17 18 18
19 22
The total number of marathoners is 16 and of those
12 run 13 miles or more
12 ___ 16
= x ____ 100
12 sdot 625 ________ 16 sdot 625
= x ____ 100
75 ____ 100
= x ____ 100
x = 75
No The statement should say that 75 of female
marathoners run 13 or more miles a week
15
6 7 8 9 1050 1 2 3 4
Sample answer Most students at Garland have 2 or
fewer siblings
16 The box plot should show that at least 50 of the
ages are between 20 and 40 years of age
17 Kudrey needs to find the median and the lower and
upper quartiles and plot those points He assumed
all quartiles would be equally long when each
quartile represents an equal number of data values
Focus on Higher Order Thinking
18 Yes the least and greatest data values The median
and quartiles may or may not be actual data values
depending on how many values are in the data
19 A box plot Since every number is different a dot
plot would only have one dot over each value which
doesnrsquot give much information The box plot would
show the median the range and where data values
are concentrated if in fact they are
20 The typical salary at this company is $24000 the
median Yes it is misleading the average is thrown
off by the outlier value of $79000
Copyright copy by Houghton Mifflin Harcourt 71 All rights reserved
9 a 56 + 43 + 62 + 63 + 33 + 34 + 38 + 51 + 59 + 59
___________________________________________ 10
= 498
The average is 498 palms
b 498 sdot 64 = 31872
There are about 3187 palms on the entire farm
Focus on Higher Order Thinking
10 55 + 57 + 57 + 58 + 59 + 59 + 59 + 59 + 59 + 61 + 62 + 62 + 63 + 64 + 66
_________________________________________________________________ 15
= 60
The mean height is 60 inches Yes it is a good sample generated randomly and contains about 20 of the entire
population so it should provide a good estimate of the mean height of all competitors But taking more samples to
gauge the variability among the samples would make for a more valid estimate
11 Sample answer Answers will vary based on each studentrsquos results but should be about 13 or 14
12 Sample answer The larger the size of the random sample the more likely it is to represent the population
accurately
LESSON 103
Guided Practice
1 (1 600) 20
2 50 51 600
3 No In the sample 4 numbers (38 26 31 and 31)
represent defective batteries which is 20 of the
total In the shipment 50 out of 600 or about 8 of
the batteries are defective
4 Sample answer A too-small or non-random sample
is likely to pick unrepresentative data values
Independent Practice
5 Shop A 10 ___ 50
times 500 = 100
Shop B 23 ____ 100
times 500 = 115
Shop C 7 ___ 25
times 500 = 140
Shop A sells 100 whole-wheat bagels
Shop B sells 115 whole-wheat bagels
Shop C sells 140 whole-wheat bagels
6 From most to least likely B A C Shop Brsquos sample
would be the most representative because it
contained the most bagels Shop Crsquos sample would
be the least representative because it contained the
fewest bagels
7 She could use either the Shop A or Shop B sample
Both use a sufficient number of bagels to be
reasonably accurate The sample from Shop C uses
too few bagels to be accurate
8 2 of the 20 T-shirts in the sample are below quality
standards Because 2 ___ 20
times 1000 = 100 the predic-
tion would be that about 100 of the 1000 T-shirts are
below quality standards This is 1 1 __ 3 times the actual
count of 75
Copyright copy by Houghton Mifflin Harcourt 72 All rights reserved
MODULE 10
Ready to Go On
1 The population is the customers in the companyrsquos
computer database The sample is biased because
the customers surveyed are more likely to value their
service
2 number of students who speak 3 or more languages
__________________________________________ size of sample
= total number of students ____________________ size of population
18 ____ 270
= x ______ 30330
18 sdot 337 ____
3 ________
270 sdot 337 ____ 3
= x ______ 30330
2022
______ 30330
= x ______ 30330
x = 2022
About 2022 students speak three or more
languages
3 Two of the random numbers 13 and 167 represent
defective MP3 players
simulated defective players
______________________ size of simulation
= defective players
______________ shipment
2 ___ 10
= x _____ 5000
2 middot 500 _______ 10 middot 500
= x _____ 5000
1000
_____ 5000
= x _____ 5000
x = 1000
Based on the sample about 1000 MP3 players are
defective
4 No the sample is too small compared to the size of
the shipment
5 Sample answer You can make predictions about
populations that are too large to survey
Copyright copy by Houghton Mifflin Harcourt 73 All rights reserved
MODULE 11 Analyzing and Comparing Data
Are You Ready
0875
1 8 ⟌ _
7000
_ -6 400
600
_ -560
40
_ -40
0
0875 875
08
2 5 ⟌ _
40
_ -4 0
0
08 80
025
3 4 ⟌ _
100
_ -80
20
_ -20
0
025 25
03
4 10 ⟌ _
30
_ -3 0
0
03 30
5 4 6 7 7 9 11 15 17
7 + 9
_____ 2 = 8
Median = 8
Mode = 7
6 36 37 40 43 44 49 50 51 56
Median = 44
Mode none
7 9 + 16 + 13 + 14 + 10 + 16 + 17 + 9
________________________________ 8
= 13
Mean = 13
8 108 + 95 + 104 + 96 + 97 + 106 + 94
________________________________ 7 = 100
Mean = 100
LESSON 111
Your Turn
2 Shape dot plots for field hockey players and
softball players have a similar spread
Center center of the field hockey dot plot is less
than the center for softball or basketball players
Spread dot plots for field hockey players and softball
players have a similar spread
3 The median is the middle value Listing the values
in order
1 4 4 4 5 5 5 6 6 6 6 7 7 8 11
In this case median 6 h
range 10 h
The median for internet usage is greater than the
median for exercise and the range is less than the
range for exercise
Guided Practice
1 Class A clustered around two areas
Class B clustered in the middle The dot plots
appear to have about half of the data clustered in
one area
2 Class A two peaks at 4 and 13 mi
Class B looks centered around 7 mi
3 Class A spread from 4 to 14 mi a wide gap with
no data
Class B spread from 3 to 9 mi
4 Class A
4 4 4 4 4 5 5 5 6 6 12 13 13 13 13 14 14
median 6
Class B
3 4 4 4 5 5 5 5 6 6 7 7 7 7 7 8 8 9
median 6
The median for both dot plots is 6 miles
5 Range for class A 14 - 4 = 10 mi
Range for class B 9 - 3 = 6 mi
6 The medians allow you to compare the centers
The ranges allow you to compare the spreads
Independent Practice
7 The dots have a relatively even spread with a peak
at 8 letters
8 The center of the graph is between 6 and 7 letters
9 The dots spread from 3 to 9 letters
10 The mean is the average
3 + 4 + 4 + 5 + 5 + 6 + 7 + 7 + 8 + 8 + 8 + 9
________________________________________ 12
74 ___ 12
asymp 617
Mean asymp 617
3 3 4 5 5 6 7 7 8 8 8 9
Because there are two middle values take their
average
6 + 7
_____ 2 = 13 ___
2 = 65
Median 65
Range 9 - 3 = 6
11 AL clustered in one small interval with an outlier to
the left
VA relatively uniform in height over the same
interval
Copyright copy by Houghton Mifflin Harcourt 74 All rights reserved
12 ALcenteredbetween8and9daysofrainVAcenteredaround10daysofrain
13 ALspreadsfrom1to12daysofrainanoutlierat1VAspreadsfrom8to12daysofrain
14 LynchburgVAhasmoreconsistentlevelsofrainandmorerainpermonthcomparedtoMontgomeryAL
15 GroupAclusteredtotheleftofsize9GroupBclusteredtotherightofsize9
16 OrderedvaluesforgroupA6577757575888888585913Thereare15itemsofdataSince15isoddthereisamiddlenumber8Sothereisnoneedtoaverageanyvalues
MedianforGroupAsize8OrderedvaluesforgroupB859999959595951010105105105115MedianforGroupBsize95
17 GroupArangewithoutlier=13-65=65withoutoutlier=9-65=25GroupBrange=115-85=3
18 SampleanswerGroupAcouldbechildrenandGroupBcouldbeadults
Focus on Higher Order Thinking
19 YesSampleansweronegroupoffivestudentscouldhavethefollowingnumberofpets12345Anothergroupoffivestudentscouldhavethefollowingnumberofpets13335Forbothgroupsofstudentsthemedianwouldbe3andtherangewouldbe4
20RangeanoutliergreatlyincreasestherangewhereasthemedianwillgenerallynotbegreatlyaffectedasitisinthemiddleofallthevaluesAdotplotwillshowboth
LESSON 112
Your Turn
3 SampleanswerTheboxeshavesimilarshapesalthoughGroupBhasashorterboxandshorterwhiskersGroupBrsquosmedianisgreaterthanGroupArsquosGroupBrsquosshorterboxmeansthemiddle50ofitsdataareclosertogetherthanthemiddle50ofGroupArsquos
4 SampleanswerTheshapeissimilartoStoreArsquosThemedianisgreaterthanStoreArsquosandlessthanStoreBrsquosTheinterquartilerangeisaboutthesameasStoreArsquosandlongerthanBrsquos
Guided Practice
1 Minimum72 Maximum88
2 Median79
3 Range88-72=16 IQR85-75=10
4 Themedianheightforhockeyplayersis70inthemedianheightforvolleyballplayersis74Thereforevolleyballplayershavethegreatermedianheight
5 Theminimumheightforhockeyplayersis64intheminimumheightforvolleyballplayersis67inSohockeyplayershavetheshortestplayer
6 IQRforhockeyplayers76-66=10IQRforvolleyballplayers78-68=10BothgroupshaveanIQRof10
7 SampleanswerMinimumandmaximumvaluesmedianrangeandIQRs
Independent Practice
8 CarAhasaminimumof165inandamaximumof210inCarBhasaminimumof160inandamaximumof205inCarAhasamedianof180inCarBhasamedianof185in
9 RangeofCarA210-165=45RangeofCarB205-160=45IQRofCarA195-170=25IQRofCarB200-175=25Bothcarshaverangesof45inandinterquartilerangesof25in
10 CarBhasagreatermediandistancethanCarATheinterquartilerangesarethesamesothemiddle50ofthejumpdistancesforthetwocarshavethesamevariability
11 CarAhaslessvariabilityinthelowestquarterofitsdataandgreatervariabilityinthehighestquarterofitsdataThevariabilityisreversedforCarB
12 CityBhasthelowestpriceof$400andalsohasthehighestpriceof$625
13 MedianforCityA$475MedianforCityB$450Difference475-450=$25CityAhasthehighermedianpriceanditis$25higher
14 SampleanswerCityBabout50ofcarsinCityBleaseforlessthan$450ascomparedtoonly25ofcarsinCityA
15 SampleanswerCityAhasagreatermediancarleasingcostthanCityBCityAhasagreaterIQRofcarleasingcoststhanCityBCityBhasamorepredictablecarleasingcostthanCityAforthemiddle50ofdatavalues
CopyrightcopybyHoughtonMifflinHarcourt 75 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U5M11indd 75 103113 221 AM
Focus on Higher Order Thinking
16 The box plot with the longer box has more variability
in the middle 50 of the values
17 You can identify the minimum and maximum values
and the range of the data You can identify the
quartiles including the lower and upper quartiles
and the median as well as the interquartile range
Together these values help you recognize the
center of the data both the median and the middle
50 It helps you to recognize how spread out the
data are overall and how spread out the middle
50 of the values are around the median A dot
plot contains all the data values which a box plot
does not
18 Sample answer The range tells you very little but
the interquartile range tells you how closely the
middle half of the data cluster around the median
LESSON 113
Your Turn
1 Team 1
Mean
44 + 47 + 67 + 89 + 55 + 76 +85 + 80 + 87 + 69 + 47 + 58 = 804
804 divide 12 = 67
Mean absolute deviation
ǀ 44 - 67 ǀ = 23 ǀ 47 - 67 ǀ = 20
ǀ 67 - 67 ǀ = 0 ǀ 89 - 67 ǀ = 22
ǀ 55 - 67 ǀ = 12 ǀ 76 - 67 ǀ = 9
ǀ 85 - 67 ǀ = 18 ǀ 80 - 67 ǀ = 13
ǀ 87 - 67 ǀ = 20 ǀ 69 - 67 ǀ = 2
ǀ 47 - 67 ǀ = 20 ǀ 58 - 67 ǀ = 11
Mean of absolute values
23 + 20 + 0 + 22 + 12 + 9 +18 + 13 + 20 + 2 + 20 + 11 = 170
170 divide 12 asymp 142
Team 2
Mean
40 + 32 + 52 + 75 + 65 + 70 +72 + 61 + 54 + 43 + 29 + 32 = 625
625 divide 12 asymp 521
Mean absolute deviation
ǀ 40 - 521 ǀ = 121 ǀ 32 - 521 ǀ = 201
ǀ 52 - 521 ǀ = 01 ǀ 75 - 521 ǀ = 229
ǀ 65 - 521 ǀ = 129 ǀ 70 - 521 ǀ = 179
ǀ 72 - 521 ǀ = 199 ǀ 61 - 521 ǀ = 89
ǀ 54 - 521 ǀ = 19 ǀ 43 - 521 ǀ = 91
ǀ 29 - 521 ǀ = 231 ǀ 32 - 521 ǀ = 201
Mean of absolute values
121 + 201 + 01 + 229 +129 + 179 + 199 + 89 +19 + 91 + 231 + 201 = 169
169 divide 12 asymp 141
Difference in means
67 - 521 = 149
149 divide 141 asymp 11
The difference of the means is about 11 times the
MAD
2 There is much more overlap between the two
distributions
Guided Practice
1 Class 1 mean
12 + 1 + 6 + 10 + 1 + 2 + 3 +10 + 3 + 8 + 3 + 9 + 8 + 6 + 8 = 90
90 divide 15 = 6
Class 2 mean
11 + 14 + 11 + 13 + 6 + 7 + 8 + 6 +8 + 13 + 8 + 15 + 13 + 17 + 15 = 165
165 divide 15 = 11
Class 1 mean absolute deviation
ǀ 12 - 6 ǀ = 6 ǀ 1 - 6 ǀ = 5 ǀ 6 - 6 ǀ = 0
ǀ 10 - 6 ǀ = 4 ǀ 1 - 6 ǀ = 5 ǀ 2 minus 6 ǀ = 4
ǀ 3 - 6 ǀ = 3 ǀ 10 - 6 ǀ = 4 ǀ 3 - 6 ǀ = 3
ǀ 8 - 6 ǀ = 2 ǀ 3 - 6 ǀ = 3 ǀ 9 - 6 ǀ = 3
ǀ 8 - 6 ǀ = 2 ǀ 6 - 6 ǀ = 0 ǀ 8 - 6 ǀ = 2
6 + 5 + 0 + 4 + 5 + 4 + 3 + 4 +3 + 2 + 3 + 3 + 2 + 0 + 2 = 46
46 divide 15 asymp 3
Class 2 mean absolute deviation
ǀ 11 - 11 ǀ = 0 ǀ 14 - 11 ǀ = 3 ǀ 11 - 11 ǀ = 0
ǀ 13 - 11 ǀ = 2 ǀ 6 - 11 ǀ = 5 ǀ 7 - 11 ǀ = 4
ǀ 8 - 11 ǀ = 3 ǀ 6 - 11 ǀ = 5 ǀ 8 - 11 ǀ = 3
ǀ 13 - 11 ǀ = 2 ǀ 8 - 11 ǀ = 3 ǀ 15 - 11 ǀ = 4
ǀ 13 - 11 ǀ = 2 ǀ 17 - 11 ǀ = 6 ǀ 15 - 11 ǀ = 2
0 + 3 + 0 + 2 + 5 + 4 + 3 + 5 +3 + 2 + 3 + 4 + 2 + 6 + 2 = 44
44 divide 15 asymp 3
2 Difference in means
11 minus 6 = 5
5 divide 3 asymp 167
3 Sample answer The variation and overlap in the
distributions make it hard to make any convincing
comparison
4 To see how statistical measures vary among the
different samples
Independent Practice
5 23 + 38 + 39 + 48 + 55 + 56 + 71 +86 + 57 + 53 + 43 + 31 = 600
600 divide 12 = 50
ǀ 23 - 50 ǀ = 27 ǀ 38 - 50 ǀ = 12
ǀ 39 - 50 ǀ = 11 ǀ 48 - 50 ǀ = 2
ǀ 55 - 50 ǀ = 5 ǀ 56 - 50 ǀ = 6
ǀ 71 - 50 ǀ = 21 ǀ 86 - 50 ǀ = 36
ǀ 57 - 50 ǀ = 7 ǀ 53 - 50 ǀ = 3
ǀ 43 - 50 ǀ = 7 ǀ 31 - 50 ǀ = 19
27 + 12 + 11 + 2 + 5 + 6 + 21 +36 + 7 + 3 + 7 + 19 = 156
156 divide 12 = 13
The mean is 50degF and the MAD is 13degF
Copyright copy by Houghton Mifflin Harcourt 76 All rights reserved
6 ǀ 23 - 8 ǀ = 15 ǀ 38 - 23 ǀ = 15
ǀ 39 - 24 ǀ = 15 ǀ 48 - 33 ǀ = 15
ǀ 55 - 40 ǀ = 15 ǀ 56 - 41 ǀ = 15
ǀ 71 - 56 ǀ = 15 ǀ 86 - 71 ǀ = 15
ǀ 57 - 42 ǀ = 15 ǀ 53 - 38 ǀ = 15
ǀ 43 - 28 ǀ = 15 ǀ 31 - 16 ǀ = 15
The difference between each average monthly
temperature for City 1 and the corresponding
temperature for City 2 is 15degF
7 50 - 15 = 35
The mean is 35degF and the MAD is 13degF The
mean for City 2 must be 15degF less than the mean
for City 1 and the MAD must be the same
8 50 - 35 = 15
15 divide 13 asymp 12
The difference in the means as a multiple of the
mean absolute deviations is about 12
9
0 4 8 12 16 20 24 28 32 36 40 44
Medians
School B
School A
0 4 8 12 16 20 24 28 32 36 40 44
Means
School B
School A
Both distributions show longer travel times for school
A The distributions of the medians show less
overlap so it is more convincing
10 State A 48 - 38 = 10
10 divide 6 asymp 17
State B 50 - 42 = 8
8 divide 4 = 2
Sample answer The difference in ages is more
significant for State A if you look at the difference in
mean ages but the difference in mean ages is more
significant in State B if you consider variability as
well
11 Smiths Range 70 - 64 = 6
Median 665
Thompsons Range 80 - 74 = 6
Median 77
77 - 665 = 105
105 divide 6 = 175
The difference in the medians is 175 times the
ranges
Focus on Higher Order Thinking
12 Sample answer Jill can reasonably expect the
median of the medians of the samples to be 35
The median of the medians should be close to the
median of the population which should be 35
The outcomes are equally likely
13 Sample answer Ramonrsquos results should produce
more reliable inferences The larger the sample
size the less variability there should be in the
distributions of the medians and means
14 Sample answer Sethrsquos statement is incorrect for any
situation in which the MADs of the population are
not very similar
MODULE 11
Ready to Go On
1 The mean for the start of the school year is given by
5 + 6 + 6 + 7 + 7 + 7 + 7 + 8 + 8 + 8 + 8 + 9 + 9 + 10
________________________________________________ 14
= 105 ____ 14
= 75 mi
The mean for the end of the school year is given by
6 + 6 + 7 + 7 + 8 + 8 + 8 + 8 + 9 + 9 + 9 + 10 + 10 + 10
__________________________________________________ 14
= 115 ___ 14
asymp 82 mi
In summary Start 75 mi End about 82 mi
2 The median is the middle value
List of ordered values for start of school year
5 6 6 7 7 7 7 8 8 8 8 9 9 10
Because there are two middle values take their
average
7 + 8
_____ 2 = 15 ___
2 = 75
Median 75
List of ordered values for end of school year
6 6 7 7 8 8 8 8 9 9 9 10 10 10
Because there are two middle values we would
generally take their average but since they are both
the same and equal to 8
Median 8
Therefore Start 75 mi End 8 mi
3 Range for start of school year 10 - 5 = 5 mi
Range for end of school year 10 - 6 = 4 mi
Therefore Start 5 mi End 4 mi
4 Median for Airplane A 210 in
Median for Airplane B 204 in
Airplane A has a greater median flight length
5 IQR for Airplane A 225 - 208 = 17 in
IQR for Airplane B 230 - 195 = 35 in
Airplane B has a greater interquartile range
Copyright copy by Houghton Mifflin Harcourt 77 All rights reserved
6 The means for the shade plants
7 + 11 + 11 + 12 + 9 + 12 + 8 + 10
______________________________ 8
= 10
The means for the sun plants
21 + 24 + 19 + 19 + 22 + 23 + 24 + 24
__________________________________ 8 = 22
Range of the shade plants 12 - 7 = 5
Range of the sun plants 24 - 19 = 5
Difference in the means 22 - 10 = 12
12 ___ 5
= 24
The difference in the means is 24 times the ranges
7 Sample answer By graphing real-world data you
can identify similarities and differences in related
groups
Copyright copy by Houghton Mifflin Harcourt 78 All rights reserved
MODULE 12 Experimental Probability
Are You Ready
1 6 ___ 10
= 6 divide 2 ______ 10 divide 2
= 3 __ 5
2 9 ___ 15
= 9 divide 3 ______ 15 divide 3
= 3 __ 5
3 16 ___ 24
= 16 divide 8 ______ 24 divide 8
= 2 __ 3
4 9 ___ 36
= 9 divide 9 ______ 36 divide 9
= 1 __ 4
5 45 ___ 54
= 45 divide 9 ______ 54 divide 9
= 5 __ 6
6 30 ___ 42
= 30 divide 6 ______ 42 divide 6
= 5 __ 7
7 36 ___ 60
= 36 divide 12 _______ 60 divide 12
= 3 __ 5
8 14 ___ 42
= 14 divide 14 _______ 42 divide 14
= 1 __ 3
075
9 4 ⟌ _
300
_ -2 80
20
_ -20
0
075
0875
10 8 ⟌ _
7000
_ -6400
600
_ -560
40
_ -40
0
0875
015
11 20 ⟌ _
300
_ -2 00
100
_ -100
0
015
038
12 50 ⟌ _
1900
_ -15 00
4 00
_ -4 00
0
038
13 67 = 67 ____ 100
= 067
14 31 = 31 ____ 100
= 031
15 7 = 7 ____ 100
= 007
16 146 = 100 + 46
= 100 ____ 100
+ 46 ____ 100
= 1 + 046
= 146
17 013 = 13
18 055 = 55
19 008 = 8
20 116 = 116
LESSON 121
Your Turn
3 Because every other number from 1 through 16 is
even choosing an even number is as likely as not
and the probability is 1 __ 2
4 There are 20 possible outcomes when picking a
marble from the jar There are 10 purple marbles
Therefore the probability of picking a purple marble
is 10 ___ 20
or 1 __ 2
5 There are 6 possible outcomes when rolling a cube
There are 2 numbers greater than 4 that can be
rolled 5 and 6 Therefore the probability of rolling a
number greater than 4 is 2 __ 6 or 1 __
3
Solutions KeyProbability
UNIT
6
Copyright copy by Houghton Mifflin Harcourt 79 All rights reserved
7 P(event) + P(complement) = 1
P(5) + P(not 5) = 1
1 __ 8 + P(not 5) = 1
P(not 5) = 7 __ 8
The probability of picking a marble that is not 5 is 7 __ 8
8 P(event) + P(complement) = 1
P(even) + P(odd) = 1
1 __ 2 + P(odd) = 1
P(odd) = 1 __ 2
The probability of rolling an odd number is 1 __ 2
Guided Practice
1 The cards are numbered 1 2 3 4 5 6 7 8 9 10
You pick a number greater than 0 8
You pick an even number 5
You pick a number that is at least 2 7
You pick a number that is at most 0 1
You pick a number divisible by 3 3
You pick a number divisible by 5 2
You pick a prime number 4
You pick a number less than the
greatest prime number 6
2 There are no green playing cards in a standard
deck so randomly picking a green card is
impossible 0
3 There are as many red cards as black cards in a
standard deck so it is as likely as not 1 __ 2
4 All of the numbers are less than 12 so they are also
less than 15 The probability is certain 1
5 There are only two numbers between 1 and 12 that
are divisible by 5 5 and 10 Therefore the probability
is unlikely close to 0
6 There are 5 possible outcomes when spinning the
spinner There are two even numbers 2 and 4
Therefore the probability of the spinner landing on
an even number is 2 __ 5
7 There are 52 possible outcomes when picking a
card from a standard deck There are 13 cards with
diamonds Therefore the probability of picking a
card with a diamond is 13 ___ 52
= 1 __ 4
8 P(event) + P(complement) = 1
P(5) + P(not 5) = 1
1 __ 6 + P(not 5) = 1
P(not 5) = 5 __ 6
The probability of not rolling 5 is 5 __ 6
9 P(event) + P(complement) = 1
P(blue) + P(not blue) = 1
1 __ 3 + P(not blue) = 1
P(not blue) = 2 __ 3
The probability of not landing on blue is 2 __ 3
10 P(event) + P(complement) = 1
P(4) + P(not 4) = 1
1 __ 5 + P(not 4) = 1
P(not 4) = 4 __ 5
The probability of not landing on 4 is 4 __ 5
11 P(event) + P(complement) = 1
P(queen) + P(not queen) = 1
4 ___ 52
+ P(not queen) = 1
P(not blue) = 48 ___ 52
= 12 ___ 13
The probability of not picking a queen is 12 ___ 13
12 Sample answer pulling a red marble out of a bag
that contains only blue marbles pulling a white
marble out of a bag that contains only white marbles
Independent Practice
13 There are 52 possible outcomes when picking from
a standard deck of cards There are 8 cards that
have an ace or a king Therefore the probability of
selecting
an ace or a king is 8 ___ 52
or 2 ___ 13
14 P(event) + P(complement) = 1
P(apple or peach) + P(not apple or peach) = 1
9 ___ 12
+ P(not apple or peach) = 1
P(not apple or peach) = 3 ___ 12
or 1 __ 4
Therefore the probability of picking a piece of fruit
that is not an apple or a peach is 3 ___ 12
or 1 __ 4
15 No it is unlikely that she will have oatmeal for
breakfast Since there are 4 choices the probability
that she will choose oatmeal is 1 __ 4 or 25
16 Purple There are a lot more plants with purple
flowers than with white flowers The probability of
selecting a white-flowered plant is 2 __ 9 while the
probability of selecting a purple-flowered plant is 7 __ 9
17 Because she has more colored T-shirts than white
T-shirts it is likely that she will pick a colored T-shirt
She has 14 total T-shirts and 10 of the shirts are
colored Therefore the probability she will choose a
colored T-shirt is 10 ___ 14
or 5 __ 7
18 1 None of the students in the class have red hair so
it is certain that a randomly chosen student will not
have red hair
Copyright copy by Houghton Mifflin Harcourt 80 All rights reserved
19 a There are 14 total coins and 8 blue coins so the
probability that the coin is blue is 8 ___ 14
or 4 __ 7
b Removing 1 of the 8 blue coins leaves 7 blue
coins Adding 3 more to the 6 red coins makes
9 red coins The total of coins in the bag is now
16 Therefore the probability of choosing a red
coin is 9 ___ 16
c Removing 1 of the 6 red coins leaves 5 red coins
Adding 3 to the 8 blue coins makes 11 blue coins
The total of coins in the bag is now 16 Therefore
the probability of choosing a red coin is 5 ___ 16
Focus on Higher Order Thinking
20 Sample answer If some marbles in a jar are heavier
than others then the heavier marbles would sink
and be less likely to be selected
21 Yes Because there are only two colors selecting
not black is equal to selecting red So
P(not black) + P(black) =P(not black) + P(not red) = 1
22 2 is the number of ways the event can happen 7 is
the number of outcomes in the sample space
landing on blue
LESSON 122
Your Turn
7 The total number of spins is 6 + 14 + 10 = 30
Red 10 ___ 30
= 1 __ 3
Yellow 14 ___ 30
= 7 ___ 15
Blue 6 ___ 30
= 1 __ 5
8 Sample answer Let 1 and 2 represent blue 3 and 4
represent white and 5 and 6 represent blue Toss
the cube 50 times to determine the experimental
probability for each color Predict the next ball will be
the color with the greatest experimental probability
Guided Practice
1 The total number of spins is 14 + 7 + 11 + 8 = 40
A 14 ___ 40
= 7 ___ 20
= 035 = 35
B 7 ___ 40
= 0175 = 175
C 11 ___ 40
= 0275 = 275
D 8 ___ 40
= 1 __ 5 = 020 = 20
2 Sample answer Write ldquoyesrdquo on 6 cards and ldquonordquo on
4 cards Draw a card at random 50 times Use the
number of ldquoyesrdquo cards drawn as the prediction
3 Use an experiment to find the number of times the
event occurs for a certain number of trials
Independent Practice
4 6 ___ 10
or 3 __ 5 It is reasonable to assume that Dreersquos
past performance is an indicator of her future
performance There is no way to accurately
represent 3 __ 5 on a number cube with 6 faces
5 Sample answer Compare the number of wins to the
total number of trials
number of wins _________________ total number of trials
= 8 ___ 48
= 1 __ 6
6 There are 20 possible outcomes when picking a
name Ryan is 1 person Therefore the probability
he is chosen is 1 ___ 20
and the probability he is not
chosen is 19 ___ 20
P(Ryan) + P(not Ryan) = 1
1 ___ 20
+ P(not Ryan) = 1
P(not Ryan) = 19 ___ 20
7 Yes because it is based on actual data of weather
patterns
8 Joan Mica hit the ball 8 ___ 48
times or about 17 of her
times at bat Meanwhile Joan hit the ball 12 ___ 40
times
or 30 of her times at bat Therefore Joan has the
greater experimental probability and is more likely to
get a hit next time
9 Gabbyrsquos experimental probability of hitting an ace
is 4 ___ 10
or 2 __ 5 Gabby could serve 16 aces in her next
40 serves because 2 __ 5 of 40 is 16
10 The experimental probability her dog wonrsquot want to
go outside is 5 ___ 12
or about 417
P(outside) + P(not outside) = 1
7 ___ 12
+ P(not outside) = 1
P(not outside) = 5 ___ 12
or 417
Focus on Higher Order Thinking
11 She did not add 40 and 60 to find the total number
of trials P(heads) = 40 ____ 100
12 Sample answer coin toss Heads represents male
and tails represents female Toss the coin 50 times
and use the results to make a prediction
13 Sample answer Make an index card to represent
each coin then pick one card at random No since
the coins are different sizes they do not each have
the same probability of getting pulled out of my
Copyright copy by Houghton Mifflin Harcourt 81 All rights reserved
LESSON 123
Your Turn
1 P(coffee + small) = number of coffee + small
_____________________ total number of orders
= 60 ____ 400
= 3 ___ 20
= 15
3 P(goId + 20 in) = number of gold + 20 in
_________________________ total number of necklaces sold
= 12 ___ 75
or 4 ___ 25
Guided Practice
1 P(female + age 22ndash39)
= number of female + age 22ndash39
__________________________ total number of patients
= 50 ____ 400
or 1 __ 8
2 Sample answer There are six possible outcomes
standard with vacuum standard with no vacuum
deluxe with vacuum deluxe with no vacuum
superior with vacuum and superior with no vacuum
Students could write the outcomes on six index
cards and put them in a box Then they can draw a
card 50 times record the results and find the
experimental probability that a customer chooses a
deluxe wash with no vacuum by dividing the
frequency of this compound event by 50 the total
number of trials
3 Find the number of occurrences of the compound
event and divide it by the total number of trials
Independent Practice
4 Divide the number of 2 piece + salad orders 33 by
the total number of orders 330
P = number of 2 piece + salad
______________________ total number of orders
= 33 ____ 330
= 1 ___ 10
5 P = number of red notebooks + 150 pages
_______________________________ total number of notebooks sold
= 60 ____ 400
= 3 ___ 20
6 P(red notebook) = number of red notebooks _____________________ total number of notebooks
= 55 + 60 + 23
____________ 400
= 138 ____ 400
= 69 ____ 200
7 12 the total is the product of 3 page-count choices
and 4 color choices
8 She left out the 53 students that read 150 pages
P(7th grade + 100 pages) = 85 ____ 250
= 17 ___ 50
9 Sample answer 8th grade the results table
suggests 8th grade students are the least likely to
have read 150 pages compared to students in 6th or
7th grade
Focus on Higher Order Thinking
10 Greater heads occurs on about half the occasions
that you roll a 6 so the compound event is half as
likely
11 Sample answer For 2 outcomes he could use even
and odd numbers For 3 outcomes he could use
1 or 2 3 or 4 and 5 or 6 For 6 outcomes he could
use each number once
12 P(male + open toe) = 11 ____ 300
P(male has open toe) = 11 ____ 150
No the first scenario
includes females and the second does not
13 No because coins are fair and the probabilities do
not appear to be equally likely
14 Sample answer On a coin heads = male and
tails = female On a number cube (1 or 2) = 6th
grade (3 or 4) = 7th grade and (5 or 6) = 8th
grade Toss the coin and roll the number cube 50
times each Record the number of outcomes that are
heads and 3 or 4
LESSON 124
Your Turn
1 024 times 550 =132 customers
2 No About 371 of the emails out of 12372 will come
back undelivered because 003 times 12372 asymp 371 The
editorrsquos prediction is too high
3 024 times 350 = 84 customers Yes because 107
customers buying two or more pairs would be more
than only 84 customers
Guided Practice
1 030 times 50 = 15 times
2 015 times 365 asymp 55 days
3 No about 1009 of the candles out of 16824 will be
returned because 006 times 16824 asymp 1009
A prediction of 812 is too low
4 No about 746 toys out of 24850 will be defective
because 003 times 24850 asymp 746 A prediction of 872 is
too high
5 98 ____ 100
= x ___ 40
= 39 ___ 40
or 39 times
No if she were late 6 out of 40 times the rate of
being on time would be only 85 in which case the
light-railrsquos claim of 98 is too high
6 18 ____ 100
= x _____ 5000
= 900 _____ 5000
or 900 students Yes the
collegersquos claim is close to the number actually
accepted
times04
times04
times50
times50
Copyright copy by Houghton Mifflin Harcourt 82 All rights reserved
7 Solve a proportion using the experimental probability
to find an expected number of events to happen
Make a prediction based on the expected number of
events
Independent Practice
8 4 ____ 100
= x ____ 200
= 8 ____ 200
or 8 students More students
moved than expected because 12 is more than 8
9 Yes 6th grade 2 ____ 100
= x ____ 250
= 5 ____ 250
or 5 students
7th grade 4 ____ 100
= x ____ 200
= 8 ____ 200
or 8 students
8th grade 8 ____ 100
= x ____ 150
= 12 ____ 150
or 12 students
Since 5 + 8 + 12 = 25 the values in the table
support his claim of 30 students
10 6 ____ 100
= x ____ 300
= 18 ____ 300
or 18 seats If an airplane is
overbooked with 310 passengers only 291 are
expected to show up since 310 times 94 asymp 291
11 006 times 600 = 36 clients If 40 clients did not pay it
would be slightly more than average
12 080 times 20 = 16 team members The coachrsquos claim is
not accurate because the average number of
students at practice is 144 ____ 8 = 8
13 He set up the fraction incorrectly it should be
1 ___ 30
= x ____ 180
Focus on Higher Order Thinking
14 1 __ 2 of 12 = 6 normal rejection rate
500 times 6 = 30 transactions rejected by a
normal gas pump
15 098 times 15000 = 14700 on-time flights Sample
answer No one week of data could be misleading
and not representative of the yearly on-time prob-
ability (because it ignores bad weather etc)
16 Sample answer No They could expect to get 96
responses with the old letter since
4 ____ 100
= x _____ 2400
= 96 _____ 2400
or 96 letters Therefore the
new letter received fewer responses
MODULE 12
Ready to Go On
1 H1 H2 T1 T2
2 6 ___ 10
= 3 __ 5
3 13 ___ 20
4 3 of the 7 total trials resulted in a sum more than 5
Therefore the experimental probability is 3 __ 7
5 I would predict he would reach first base 24 times
because 3 ___ 10
= x ___ 80
= 24 ___ 80
or 24 times
6 You can use the experimental probability based on
observation or simulation to set up a proportion and
use the proportion to predict a value
times15
times15
times24
times24
times2
times2
times3
times3
times2
times2
times25
times25
times8
times8
Copyright copy by Houghton Mifflin Harcourt 83 All rights reserved
MODULE 13 Theoretical Probability and
Simulations
Are You Ready
075
1 4 ⟌ _
300
_ -2 80
20
_ -20
0
075 = 75
04
2 5 ⟌ _
20
_ -2 0
0
04 = 40
09
3 10 ⟌ _
90
_ -9 0
0
09 = 90
035
4 20 ⟌ _
700
_ -6 00
1 00
_ -1 00
0
035 = 35
0875
5 8 ⟌ _
7000
_ thinsp-6 400
600
_ -560
40
_ -40
0
0875 = 875
005
6 20 ⟌ _
100
_ -1 00
0
005 = 5
076
7 25 ⟌ _
1900
_ -17 50
1 50
_ -1 50
0
076 = 76
046
8 50 ⟌ _
2300
_ -20 50
3 00
_ -3 00
0
046 = 46
9 1 - 1 __ 5 = 5 __
5 - 1 __
5
= 4 __ 5
10 1 - 2 __ 9 = 9 __
9 - 2 __
9
= 7 __ 9
11 1 - 8 ___ 13
= 13 ___ 13
- 8 ___ 13
= 5 ___ 13
12 1 - 3 ___ 20
= 20 ___ 20
- 3 ___ 20
= 17 ___ 20
13 8 ___ 15
times 5 __ 8 =
18 ___ 315
times 5 1 ___
8 1
= 1 __ 3
14 2 __ 9 times 3 __
4 =
12 __ 39
times 3 1 ___
4 2
= 1 __ 6
15 9 ___ 16
times 12 ___ 13
= 9 ___ 416
times 12 3 _____
13
= 27 ___ 52
16 7 ___ 10
times 5 ___ 28
= 17 ___
210 times 5
1 ____
28 4
= 1 __ 8
LESSON 131
Your Turn
2 The probability of an event is the ratio of the number
of ways the event can occur to the total number of
equally likely outcomes Therefore
P(rolling a 3 or 4) =
number of sides with 3 or 4 ________________________ total number of sides on cube
= 2 __ 6 = 1 __
3
3 The total number of outcomes in the sample space
is the denominator of the formula for theoretical
probability
Copyright copy by Houghton Mifflin Harcourt 84 All rights reserved
Guided Practice
1
Basket A Basket B
Total number of outcomes5 + 3 + 8
= 16
7 + 4 + 9
= 20
Number of red balls 3 4
P(win) =
Number of red balls
_____________________ Total number of outcomes
3 ___
16 4 ___
20 = 1 __
5
2 To compare the two probabilities of 1 __ 5 and 3 ___
16 use
the least common denominator of 80
1 __ 5 = 16 ___
80
3 ___ 16
= 15 ___ 80
Therefore 16 ___ 80
gt 15 ___ 80
so 1 __ 5 gt 3 ___
16
Choosing Basket B gives you a better chance of
winning
3 There are a total of 6 odd sections The total number
of sections (odd and even) is 11
P(odd) = number of odd sections ____________________ total number of sections
= 6 ___ 11
4 There are a total of 5 even sections The total
number of sections (odd and even) is 11
P(even) = number of even sections ____________________ total number of sections
= 5 ___ 11
5 The total number faces on a number cube is 6 and
rolling either a 3 or 4 is equal to 2 possibilities
P(rolling a 3 or 4) = number of sides with 3 or 4 ________________________ total number of sides on cube
= 2 __ 6 = 1 __
3
6 Sample answer No but it might be reasonably
close
7 Divide the number of ways the event can occur
by 20
Independent Practice
8 P(yellow) = number of yellow sections
_____________________ total number of sections
= 2 __ 6
= 1 __ 3 033 or 33
9 P(blue or green) = number of blue or green sections
___________________________ total number of sections
= 8 ___ 12
= 2 __ 3 067 or 67
10 P(cherry) = number of cherry cough drops
_________________________ total number of cough drops
= 4 ___ 14
= 2 __ 7 029 or 29
11 P(black card) = number of black cards __________________ total number of cards
= 26 ___ 52
= 1 __ 2 050 or 50
12 P(lime) = number of limes ________________________ total number of pieces of fruit
= 12 - 5 ______ 12
= 7 ___ 12
058 or 58
13 There are a total of 20 DVDs There are 12 DVDs
that are not comedies (5 science fiction plus
7 adventure)
P(not a comedy)
= number of DVDs which are not comedies _________________________________ total number of DVDs
= 5 + 7 _________
5 + 7 + 8 = 12 ___
20
= 3 __ 5 060 or 60
14 There are a total of 6 faces on a number cube There
are 2 faces (3 and 4) that are greater than 2 and
less than 5 which means 2 possibilities
P(greater than 2 and less than 5)
= number of sides with 3 and 4 ________________________ total number of sides on cube
= 2 __ 6
= 1 __ 3 033 or 33
15 9 represents the ways the event can occur
13 represents the number of equally likely outcomes
16 There are a total 16 coins and there are 6 coins that
are greater than 5 cents Therefore
P(coin worth more than 5 cents)
= number of coins worth more than 5 cents _________________________________ total number of coins
= 6 ___ 16
or 3 __ 8
The event is choosing a dime or a quarter and 6 of
the 16 coins are dimes or quarters
Focus on Higher Order Thinking
17 Sample answer Riley divided the number of petunia
seeds by the number of begonia seeds rather than
the total number of seeds The correct probability is
5 ______ 5 + 15
= 5 ___ 20
= 1 __ 4
times16
times16
times5
times5
Copyright copy by Houghton Mifflin Harcourt 85 All rights reserved
18 a The total number of students in the club is 35
There are 20 seventh graders Therefore
P(seventh grader) =
number of seventh graders
______________________ total number of students
= 20 ___ 35
= 4 __ 7
There are 15 eighth graders in the club Therefore
P(eighth grader) =
number of eighth graders
_____________________ total number of students
= 15 ___ 35
= 3 __ 7
Because 4 __ 7 gt 3 __
7 choosing a seventh grader is
more likely
b No each student has the same probability of
being selected 1 ___ 35
19 Sample answer The number of trials is twice the
number of marbles in the jar If the probabilities for
each color were the same the number of times that
color was drawn would be twice the number of
marbles with that color in the jar
20 Red The theoretical probability of choosing red is
P(red) = number of red marbles ___________________ total number of marbles
= 8 ___ 20
The experimental probability of choosing red is
14 ___ 40
or 7 ___ 20
Therefore the difference in the theoretical probability
and experimental probability of choosing a red
marble is 8 ___ 20
- 7 ___ 20
= 1 ___ 20
For blue the theoretical probability is
P(blue) = number of blue marbles ____________________ total number of marbles
= 10 ___ 20
The experimental probability is 16 ___ 40
= 8 ___ 20
Therefore the difference in the theoretical probability
and experimental probability of choosing a blue
marble is 10 ___ 20
- 8 ___ 20
= 2 ___ 20
= 1 ___ 10
For yellow the theoretical probability is
P(yellow) = number of yellow marbles
_____________________ total number of marbles
= 2 ___ 20
The experimental probability is 10 ___ 40
= 5 ___ 20
Therefore the difference in the theoretical probability
and experimental probability of choosing a yellow
marble is 5 ___ 20
- 2 ___ 20
= 3 ___ 20
Choosing a red marble has the smallest difference
between theoretical and experimental probability
LESSON 132
Your Turn
3 P(ham sandwich) =
number of combinations containing ham
_________________________________ total number of sandwich combinations
= 4 ___ 12
= 1 __ 3
4 P(sandwich containing Swiss cheese) =
number of combinations containing Swiss
__________________________________ total number of sandwich combinations
= 6 ___ 12
= 1 __ 2
5 To find the sample space make lists of possible
codes First make a list of codes that start with 0
and have 0 as the second digit
0 0 0 0
0 0 0 1
0 0 1 0
0 0 1 1
List of codes that start with 0 and have 1 as the
second digit
0 1 0 0
0 1 0 1
0 1 1 0
0 1 1 1
List of codes that start with 1 and have 0 as the
second digit
1 0 0 0
1 0 0 1
1 0 1 0
1 0 1 1
List of codes that start with 1 and have 1 as the
second digit
1 1 0 0
1 1 0 1
1 1 1 0
1 1 1 1
In total the number of possible outcomes is 16
There are six codes with exactly two 0s
0 0 1 1
0 1 0 1
0 1 1 0
1 0 0 1
1 0 1 0
1 1 0 0
This means the number of outcomes for a code with
exactly two 0s is 6 Therefore
P(Code exactly two 0s)
= number of favorable outcomes ____________________________ total number of possible outcomes
= 6 ___ 16
= 3 __ 8
Copyright copy by Houghton Mifflin Harcourt 86 All rights reserved
Guided Practice
1
1 2 3 4 5 6
11 sdot 1
= 1
1 sdot 2
= 2
1 sdot 3
= 3
1 sdot 4
= 4
1 sdot 5
= 5
1 sdot 6
= 6
22 sdot 1
= 2
2 sdot 2
= 4
2 sdot 3
= 6
2 sdot 4
= 8
2 sdot 5
= 10
2 sdot 6
= 12
33 sdot 1
= 3
3 sdot 2
= 6
3 sdot 3
= 9
3 sdot 4
= 12
3 sdot 5
= 15
3 sdot 6
= 18
44 sdot 1
= 4
4 sdot 2
= 8
4 sdot 3
= 12
4 sdot 4
= 16
4 sdot 5
= 20
4 sdot 6
= 24
55 sdot 1
= 5
5 sdot 2
= 10
5 sdot 3
= 15
5 sdot 4
= 20
5 sdot 5
= 25
5 sdot 6
= 30
66 sdot 1
= 6
6 sdot 2
= 12
6 sdot 3
= 18
6 sdot 4
= 24
6 sdot 5
= 30
6 sdot 6
= 36
2 There are 15 entries in the table that are multiples
of 4 The total number of entries in the table is 36
P(multiple of 4) = number of multiples of 4
_________________________ total number of entries in table
= 15 ___ 36
3 There are 23 entries in the table that are less than
13 The total number of entries is 36
P(less than 13) = number of entries less than 13 _________________________ total number of entries in table
= 23 ___ 36
4 H
HHH HHT
H
H
Coin 1
List
Coin 2
Coin 3 T
T
HTH HTT
H T
T
H
H T
THH THT
T
H T
TTH TTT
Coin 1
List
Coin 2
Coin 3
5 Count the total number of outcomes in the list 8
6 The only way to get three tails is TTT
7 P = number of outcomes with 3 tails __________________________ total number of outcomes
= 1 __ 8
8 There are 3 way(s) to obtain exactly two heads
HHT HTH THH
P = number of outcomes with exactly 2 heads
__________________________________ total number of possible outcomes
= 3 __ 8
9 You need to know the number of equally likely
outcomes in the sample space
Independent Practice
10
Checkered
Red
Checkered
Red
Blue
Black
Checkered
Red
Checkered
Red
Blue
Black
Checkered
Red
Checkered
Red
Blue
Black
Shirt Pants Shoes
Yellow
Red
Green
11 There are 6 combinations that include red shoes
The total number of combinations is 12 Therefore
P(red shoes) = number of combinations with red shoes ________________________________ total number of combinations
= 6 ___ 12
= 1 __ 2
12 There are four combinations that do not include red
Shirt Pants Shoes
Green Blue Checkered
Green Black Checkered
Yellow Blue Checkered
Yellow Black Checkered
P(no red) = number of outfits with no red _______________________ total number of outfits
= 4 ___ 12
= 1 __ 3
13 Let the other three band members be A B and C
The list of possible combinations is
Rhee Pamela
Rhee A
Rhee B
Rhee C
Pamela A
Pamela B
Pamela C
A B
A C
B C
There is a total of 10 combinations Of these only 1
has Rhee and Pamela so
P(Rhee and Pamela)
= Rhee and Pamela ________________________ total number of combinations
= 1 ___ 10
Copyright copy by Houghton Mifflin Harcourt 87 All rights reserved
14 The sample space can be found from adding all
possible combinations of the two numbers
1 2 3 4 5 6
11 + 1
= 2
1 + 2
= 3
1 + 3
= 4
1 + 4
= 5
1 + 5
= 6
1 + 6
= 7
22 + 1
= 3
2 + 2
= 4
2 + 3
= 5
2 + 4
= 6
2 + 5
= 7
2 + 6
= 8
33 + 1
= 4
3 + 2
= 5
3 + 3
= 6
3 + 4
= 7
3 + 5
= 8
3 + 6
= 9
44 + 1
= 5
4 + 2
= 6
4 + 3
= 7
4 + 4
= 8
4 + 5
= 9
4 + 6
= 10
55 + 1
= 6
5 + 2
= 7
5 + 3
= 8
5 + 4
= 9
5 + 5
= 10
5 + 6
= 11
66 + 1
= 7
6 + 2
= 8
6 + 3
= 9
6 + 4
= 10
6 + 5
= 11
6 + 6
= 12
There is a total of 36 possible sums Of these there
are 10 less than 6
P(sum is less than 6)
= number of sums less than 6 ____________________________ total number of possible outcomes
= 10 ___ 36
= 5 ___ 18
15 The sample space can be found from a tree
diagram
Khakis
Shorts
Shirt Pants Shoes
Collared Jeans
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Khakis
Shorts
T-shirt Jeans
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Total number of possible outcomes is 18 the
number of combinations which include jeans but
not sneakers is 4 Therefore
P(jeans but not sneakers)
= number of outfits with jeans no sneakers
_________________________________ total number of possible outcomes
= 4 ___ 18
= 2 __ 9
16 For each chair lift there are 6 possible trails So you
can multiply the number of choices of chair lifts (3)
by the number of trails (6)
17 Because there are 3 choices for the first item and
2 for the second there are 3 middot 2 = 6 possible
outcomes
18 There is a total of 30 possible shoe sizes Of these
the number of red shoes size 9 or larger is 7
Therefore
P(red and size 9 or larger) =
number of red shoes size 9 or larger
______________________________ total number of possible outcomes
= 7 ___ 30
Focus on Higher Order Thinking
19 Sondra orders one item from each column There
are 4 main dishes 4 vegetables and two sides so
the sample space is 4 sdot 4 sdot 2 = 32 The possible
outcomes of Sondrarsquos order are shown in the tree
diagram
Carrots
Sweet potato
Pasta
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Carrots
Sweet potato
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Carrots
Sweet potato
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Carrots
Sweet potato
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Salmon
Beef
Pork
Copyright copy by Houghton Mifflin Harcourt 88 All rights reserved
There are 8 total number of outcomes that include
salmon Therefore
Sondra P(salmon) = 8 ___ 32
= 1 __ 4
Gretchen orders a main dish and a vegetable There
are 4 main dishes and 4 vegetables so the sample
space is 4 sdot 4 = 16 The possible outcomes of
Gretchenrsquos order are shown in the tree diagram
Carrots
Sweet potato
PastaPeas
Asparagus
Carrots
Sweet potato
Peas
Asparagus
Carrots
Sweet potato
Peas
Asparagus
Carrots
Sweet potato
Peas
Asparagus
Salmon
Beef
Pork
There are 4 total number of outcomes that include
salmon Therefore
Gretchen (salmon) = 4 ___ 16
= 1 __ 4
Because the probabilities for Sondra and Gretchen
are equal neither has a greater probability of getting
a meal that includes salmon
20 a For possible two-digit codes consider first codes
that begin with 1 12 13 14 15 There are a total
of 4 possible codes This pattern continues for
each of the 5 digits and therefore we have a total
of 4 + 4 + 4 + 4 + 4 = 20 possible two-digit
codes (four codes each that begin with each of
the numbers 1ndash5)
For possible three-digit codes there are 12
possible codes that begin with 1 and so there are
12 possible codes for each of the numbers 1ndash5
making a total of 5 sdot 12 = 60 possible three-digit
codes
We can predict the number of possible five-digit
codes because we know there are 60 possible
three-digit codes and for each of these there are
only two digits that can be added to the end of
each code to make them five-digit codes These
are the digits that were not used in the three-digit
code and they have two possible orders for a
total of 60 sdot 2 = 120 possible five-digit codes
As a concrete example again consider the three-
digit codes that begin with 1 Tacking on the digits
which are not included in these three-digit codes
in both orders we have 12345 12354 12435
12453 12534 12543 13245 13254 13425
13452 13524 13542 14235 14253 14325
14352 14523 14532 15234 15243 15324
15342 15423 15432 If we do the same for the
three-digit codes beginning with 2ndash5 we will find
the 120 possible five-digit codes
b Now that the numbers can repeat for two-digit
codes take the 20 codes from before and add five
more codes (11 22 33 44 55) which makes a
total of 25 two-digit codes
For three-digit codes take the 60 codes from
before and add the 5 codes that have all digits
the same plus codes which have two digits
which are repeats To find these consider first the
codes with the first two digits the same 112 113
114 115 221 223 224 225 331 332 334 335
441 442 443 445 551 552 553 554 There
are 20 possible codes There are also 20 possible
codes with the last two digits the same Finally
consider the codes where the first and last digits
are the same For the repeated digit 1 we have
121 131 141 151 or 4 possible codes For each
of the digits 1ndash5 we have 4 possible codes for a
total of 4 sdot 5 = 20 Therefore the overall total
60 + 5 + 20 + 20 + 2 = 125 three-digit codes
To solve for how many possible 5 digit codes
there are notice a pattern in the codes For
two-digit codes the total possible codes is the
number of possible digits raised to the power
equal to the number of digits in the code or
52 = 25 For three-digit codes the number of
possible digits is the same and the number
of digits in the code is 3 so we have 53 = 125
Following this pattern there are 55 = 3125
possible five-digit codes
c Sample answer The better choice is to have the
digits repeat there are more unique codes with
repeated digits than without so it would be more
difficult for someone to guess a code for a locker
LESSON 133
Your Turn
1 There are 4 numbers less than 5 on a standard
number cube There are 6 possible outcomes so
P(number less than 5) = 4 __ 6 = 2 __
3
The number of events is 250 Therefore
P(number less than 5) times Number of events =
2 __ 3 times 250 = 16666 or about 167 times
Copyright copy by Houghton Mifflin Harcourt 89 All rights reserved
2 Set up a proportion The probability of getting
heads is 1 __ 2
1 __ 2 = x ___
18
1 __ 2 = x ___
18
x = 9
about 9 times
3 There are 17 total marbles and 8 are red Therefore
P(red) = 8 ___ 17
P(not red) = 1 - 8 ___ 17
= 9 ___ 17
It is more likely that he picks a marble that is not red
4 No Sample answer There is a total of 71 bills in the
bag and there are 11 bills worth $6 or more
Therefore
P(bill worth $6 or more) = 11 ___ 71
This is about a 15 probability so it is not likely you
will win enough to pay for your ticket
Guided Practice
1 An equally likely chance means that the probabilities
of being assigned to each crew are the same and
since there are three possibilities each has a
probability of 1 __ 3
Apartment 1 __ 3 Condo 1 __
3 House 1 __
3
The probability of being assigned to house crew is 1 __ 3
Set up and solve a proportion
1 __ 3 = x ___
18
1 __ 3 = x ___
18
x = 6
This means that Bob can expect to be assigned to
the house crew about 6 times out of 18
2 Since half of the ticket holders will receive a prize
this means that 300 divide 2 = 150 people will receive a
prize Because they are equally likely to receive one
of three prizes the probability of winning each of the
prizes is 1 __ 3 so the probability of winning a movie
ticket is 1 __ 3 The number of events is 150 Therefore
P(movie ticket) times Number of events = 1 __ 3 times 150 =
50 or 50 people are predicted to win a movie ticket
3 The total number of students in Mr Jawaranirsquos class
is 28 The probabilities of picking a student at
random with a certain eye color are
P(hazel) = 9 ___ 28
P(brown) = 10 ___ 28
P(blue) = 7 ___ 28
P(green) = 2 ___ 28
The event with the greatest probability is choosing a
person with brown eyes
4 You can find and compare probabilities Or you can
use probability to set up and solve a proportion or
an equation that relates the probability to the
unknown quantity
Independent Practice
5 The total number of marbles in the bag is 9 The
number of white or gray marbles is 3 Therefore
P(white or gray) = 3 __ 9 = 1 __
3
The number of events is 45 The equation to make a
prediction is then
P(white or gray) times Number of events = 1 __ 3 times 45 = 15
You can expect to get 15 white or gray marbles
6 A spinner which has an equal likelihood to land on
green or yellow means that the number of green and
yellow sections must be equal More likely to land on
red means that there must be more red sections
than yellow or green A Sample answer is
Y GRR
R R
RR
7 Because half the deck is red the probability of
drawing a red card is 1 __ 2 Because there are three
face cards for each of four suits there are 3 sdot 4 = 12
face cards and the probability of drawing a face
card is 12 ___ 52
To compare 1 __ 2 and 12 ___
52 use the least
common denominator of 52 so that 1 __ 2 = 26 ___
52 Given
that 12 ___ 52
lt 26 ___ 52
the probability of drawing a red card
is higher than of drawing a face card and it is more
likely that Dawn draws 2 red cards
8 The total number of aces in a deck is 4 Therefore
P(ace) = 4 ___ 52
= 1 ___ 13
The number of events is 39 The equation to make a
prediction is then
P(ace) middot Number of events = 1 ___ 13
times 39 = 3
He is predicted to draw an ace 3 times
9 The total number of red cards is 26 Therefore
P(red card) = 26 ___ 52
= 1 __ 2
The number of events is 1000 The equation to
make a prediction is then
P(red card) sdot Number of events = 1 __ 2 sdot 1000 = 500
The player is predicted to turn over a red card as the
first card 500 times
10 The sample space can be found from adding all
possible combinations of the two numbers
times6
times6
times9
times9
Copyright copy by Houghton Mifflin Harcourt 90 All rights reserved
1 2 3 4 5 6
1 2 3 4 5 6 7
2 3 4 5 6 7 8
3 4 5 6 7 8 9
4 5 6 7 8 9 10
5 6 7 8 9 10 11
6 7 8 9 10 11 12
There is a total of 36 possible sums Of these there
are 5 ways to roll a sum of 8 and 2 ways to roll a
sum of 11 The probabilities are
P(sum of 8) = 5 ___ 36
P(sum of 11) = 2 ___ 36
Because the probability of rolling a sum of 8 is
greater than that of rolling a sum of 11 ( 5 ___ 36
gt 2 ___ 36
) John is more likely to win
11 There are 5 possible numbers greater than 15 so
P(greater than 15) = 5 ___ 20
= 1 __ 4
The number of events is 180 The equation to make
a prediction is then
P(greater than 15) times Number of events =
1 __ 4 times 180 = 45
The chosen number will be greater than 15 for 45
days in the school year
12 The sample space for a standard cube is 36 and
there are 3 combinations that will have a sum of 4
so P(sum of 3) = 3 ___ 36
= 1 ___ 12
The number of events is 36 The equation to make a
prediction is then
P(sum of 3) times Number of events = 1 ___ 12
middot 36 = 3
Eben is predicted to roll a sum of 4 a total of 3 times
13 Sample answer No Every time you flip a coin the
probability of heads is 1 __ 2 but in reality you could flip
a coin many times and have it land heads up every
time
14 Sample answer A bag of marbles contains red and
blue marbles that are different sizes Since it is easy
to feel the difference between the two colors all of
the outcomes are not equally likely You cannot make
a prediction using theoretical probability
Focus on Higher Order Thinking
15 Sample answer What is the theoretical probability
that the coin lands on heads and you pick a marble
that is not green
The probability that the coin lands on heads is 1 __ 2
and the probability that the picked marble is not
green is 3 + 9 _________
3 + 8 + 9 = 12 ___
20 The product of these two
probabilities is 1 __ 2 times 12 ___
20 = 12 ___
40
16 Sample answer It is much more likely that he rolls a
5 or the coin lands on heads
The probability that Horace rolls a 5 and the coin
lands on heads is given by
P(5 and heads) = 1 __ 2 times 1 __
6 = 1 ___
12
In the case where Horace rolls a 5 or the coin lands
on heads the probability is given by
P(5 or heads) = 1 __ 6 + 1 __
2 - 1 __
6 times 1 __
2 = 7 ___
12
17 Yes but only theoretically because in reality nothing
can occur 05 times Sample answer The probability
that a flipped coin lands heads up is 1 __ 2 so in 75 flips
you can expect heads about 75 ___ 2 or 375 times
LESSON 134
Your Turn
1 Sample answer (data and percent will vary)
Trial Numbers generated 3 Males first
1 0 0 1 No
2 0 1 No
3 1 No
4 0 1 No
5 1 No
6 0 0 0 1 Yes
7 0 0 1 No
8 0 1 No
9 1 No
10 0 0 0 0 1 Yes
For these data the experimental probability that the
elephant gives birth to 3 male calves before having a
female calf is 2 ___ 10
or 20
2 Sample Answer (data and percent will vary)
Trial Numbers generated Correct answers
1 1 0 1 1 0 3
2 0 1 0 0 1 2
3 0 0 0 0 1 1
4 0 0 1 1 0 2
5 1 1 1 1 1 5
6 1 0 0 0 0 1
7 1 0 1 1 0 3
8 1 0 1 0 0 2
9 0 1 1 1 1 4
10 0 0 0 0 0 0
The experimental probability that he gets at least 2
questions right is 7 ___ 10
= 70
Copyright copy by Houghton Mifflin Harcourt 91 All rights reserved
Guided Practice
1 Since there is a 30 or 3 ___ 10
chance of drought let
the numbers 1 to 3 represent years with a drought
and the numbers 4 to 10 represent years without
a drought Since we are interested in the next 4
years perform multiple trials generating 4 random
numbers each time
2
Trial Numbers generated Drought years
1 10 3 5 1 2
2 10 4 6 5 0
3 3 2 10 3 3
4 2 10 4 4 1
5 7 3 6 3 2
6 8 4 8 5 0
7 6 2 2 8 2
8 6 5 2 4 1
9 2 2 3 2 4
10 6 3 1 5 2
3 In 8 out of the 10 trials there was a drought in at
least one of the years The experimental probability
of a drought in at least 1 of the next 4 years is
8 ___ 10
= 80
4 Sample answer Generate whole numbers from
1 to 4 Let 1 to 3 represent the event occurring
and 4 represent the event not occurring
Independent Practice
5 There is only 1 trial Trial 6 where it took exactly
4 contestants to get a winner
6 Since 1 out of 10 trials resulted in exactly
4 contestants the probability is 1 ___ 10
= 10
7 The trials for which at least 4 hurricanes struck are
Trials 2 and 7 or 2 out of 10 trials Therefore the
probability is 2 ___ 10
= 20
8 It is fewer than expected based on the simulation
9 It is unlikely but it is not impossible Each of the 3
numbers could be any number from 1 to 10
However there are 10 possible first numbers 10
possible second numbers and 10 possible third
numbers or a total of 1000 possible numbers when
generating three numbers from 1 to 10 The
probability of generating three 10s is 1 _____ 1000
10 Sample answer Use the numbers 1ndash5 where 1 2
and 3 represent packs which contain a player from
Erikarsquos favorite team Generate numbers randomly
and stop when you get a 1 2 or 3
Trial Numbers generated Number of Packs
1 3 1
2 4 2 2
3 2 1
4 1 1
5 2 1
6 4 5 3 2
7 4 2 2
8 4 5 2 1
9 4 4 3 3
10 5 1 2
The average number of packs she needs to buy is
1 + 2 + 1 + 1 + 1 + 2 + 2 + 1 + 3 + 2
_________________________________ 10
= 16 ___ 10
= 1 3 __ 5
packs Since she cannot buy a fraction of a pack
she must buy 2 packs
Focus on Higher Order Thinking
11 Sample answer The probability that she makes a
shot is 375 = 3 __ 8 Use the whole numbers from 1 to
8 with 1ndash3 representing shots she makes and 4ndash8
representing shots she misses For each new trial
generate 10 random numbers Count the number
of times 1 2 or 3 appears in each trial Divide the
number of trials in which she made at least 3 shots
by the total number of trials
12 Sample answer Their simulation was not
appropriate perhaps because they chose an
incorrect model You would expect there to have
been exactly 4 heads on more of the trials and
more variation in the number of heads in general
MODULE 13
Ready to Go On
1 P(red) = number of red marbles ___________________ total number of marbles
= 12 ___________________ 12 + 12 + 15 + 9 + 12
= 12 ___ 60
= 1 __ 5 020 or 20
2 P(diamond or spade)
= number of diamonds and spades
___________________________ total number of cards
= 13 + 13
_______ 52
= 26 ___ 52
= 1 __ 2 050 or 50
3 The most likely color of marble chosen is the most
common color in this case green
Copyright copy by Houghton Mifflin Harcourt 92 All rights reserved
4 In order to find the experimental probability count
the number of trials in which 1 occurs at least once
In this case there are 4 trials that generated a 1
Therefore the experimental probability is 4 ___ 10
or
40
5 Sample answer You can find the theoretical
probability of an event and then use it to make a
prediction by setting up a proportion
Copyright copy by Houghton Mifflin Harcourt 93 All rights reserved
24 15 + ( -15 ) + 200 = 200
25 -500 + ( -600 ) + 1200 = 100
26 9 + ( -22 ) = -13 the team lost 13 yards
27 -55 + 275 = 220 the teamrsquos profi t was $220
28 -47 + 47 = 0 Alexrsquos new balance is $0
29 Sample answer 10 and -2 and 12 and -4
30 Bart won Bartrsquos score = 123 + ( -180 ) = -57
points Samrsquos score = 185 + ( -255 ) = -70 points
-57 gt -70 so Bart has the greater score
Focus on Higher Order Thinking
31 Start at -4 and move 3 to the right to reach -1
Start at 3 and move 4 to the left to reach -1
The sums are equivalent by the Commutative
Property of Addition
32 The weight is dropped from 4 feet above the surface
Add -12 to represent the distance the weight falls
before it hits the bottom 4 + ( -12 ) = -8 The water
is 8 feet deep
33 Sample answer A model with more positive
counters than negative counters represents a sum of
two integers whose sum is positive
34 The sign of the other integer is positive and its value
is 6 or greater Sample explanation If you start at
-5 on a number line you have to move to the right 6
or more units to get a sum that is positive
LESSON 13
Your Turn
4 -7 - 2 = -7 + ( -2 )
-7 + ( -2 ) = -9
5 -1 - ( -3 ) = -1 + 3
-1 + 3 = 2
6 3 - 5 = 3 + ( -5 )
3 + ( -5 ) = -2
7 -8 - ( -4 ) = -8 + 4
-8 + 4 = -4
Guided Practice
1 5 - 8 = -3 Start with 5 positive counters
Add 3 zero pairs and remove 8 positive counters
3 negative counters are left so the difference is -3
2 -5 - ( -3 ) = -2 Start with 5 negative counters
and remove 3 negative counters 2 negative
counters are left so the difference is -2
3 -4 - 5 = -4 + ( -5 ) = -9
0-1-2-3-4-5-6-7-8-9 4 1 - 4 = 1 + -4 = -3
0 1 2 3 4-1-2-3-4 5 8 - 11 = 8 + ( -11 ) = -3
6 -3 - ( -5 ) = -3 + 5 = 2
7 15 - 21 = 15 + ( -21 ) = -6
8 -17 - 1 = -17 + ( -1 ) = -18
9 0 - ( -5 ) = 0 + 5 = 5
10 1 - ( -18 ) = 1 + 18 = 19
11 15 - 1 = 14
12 -3 - ( -45 ) = -3 + 45 = 42
13 19 - ( -19 ) = 19 + 19 = 38
14 -87 - ( -87 ) = -87 + 87 = 0
15 To subtract an integer add its opposite Sample
example 6 - 8 = 6 + ( -8 ) = -2
Independent Practice
16 To fi nd the change to Theorsquos account subtract the
initial balance -$4 from the fi nal balance $25
25 - ( -4 ) = 25 + 4 = 29
The overall change is $29
17 To fi nd the change in elevation subtract the
beginning elevation of -225 feet from the fi nal
elevation of -127 feet
-127 - ( -225 ) = -127 + 225 = 98
The change in elevation was 98 feet
18 Subtract the low temperature -2degF from the high
temperature 90degF
90 - ( -2 ) = 92
The difference between the high and low
temperatures is 92degF
19 Subtract Cheyennersquos score at the end of her turn
from her score at the start of her turn to fi nd the
change in Cheyennersquos score during her turn
-425 - ( -275 ) = -425 + 275 = -150
The change in Cheyennersquos score is -150 points
20 a Final temperature - initial temperature = change
in temperature
Gas A -8 - ( -21 ) = -8 + 21 = 13
13degC increase
Gas B 12 - ( -12 ) = 12 + 12 = 24
24degC increase
Gas C -15 - ( -19 ) = -15 + 19 = 4
4degC increase
b Negative the fi nal temperatures will be less than
the initial temperature because the gas is cooler
So the difference in temperatures will be negative
21 Diet Chow the catrsquos weight changed by
-8 + ( -18 ) = -26 ounces with Diet Chow and
3 + ( -19 ) = -16 ounces with Kitty Diet
Focus on Higher Order Thinking
22 Sample answer Susanne owed her sister $4 Then
she borrowed $10 more How much does Susanne
owe her sister in all
23 Tom found -11 - 4 instead of -11 - ( -4 ) To
subtract -4 he should add the opposite of -4
-11 + 4 = -7
Copyright copy by Houghton Mifflin Harcourt 3 All rights reserved
24 YouranswerwillbegreaterthantheintegeryoustartedwithbecausewhenyousubtractanegativeintegeryouadditsoppositeapositiveintegerForexample-5-( -3)=-5+3=-2-2gt-5
25 -16-21-26subtract5togetthenextterm
LESSON 14
Your Turn
1 Starts-Descends+Ascends-40-13+18=-53+18 =-3535feetbelowthecaveentrance
3 Usenegativeintegersforcheckamountsanduseapositiveintegerforamountdeposited-35+( -45)+180=-80+180 =100$100increase
4 JimJim-10-18+5-12=-10-18-12+5 =-( 10+18+12)+5 =-40+5 =-35Jimrestedat-35feet(35feetbelowthesurface)Carla0-20+5-18=0+5-20-18 =0+5-( 20+18) =5-38 =-33Carlarestedat-33feet(33feetbelowthesurface)
Guided Practice
1 -15+ 9- 12= -6- 12 =-1818feetbelowsealevel
2 -23+5-7=-18-7 =-25-25degF
3 50-40+87-30=10+87-30 =97-30 =6767points
4 -6+15+15=-6+30 =24
5 9- 4- 17= 9- 21 =-12
6 50-42+10=8+10 =18
7 6+13+7-5=19+2 =21
8 65+43-11=108-11 =97
9 -35-14+45+31=-49+76 =27
10 -12+6-4=-6-4 =-10-34-3+39=-37+39 = 2 -10lt2( -12+6-4)lt( -34-3+39)
11 21-3+8=18+8 =26-14+ 31- 6= 17- 6 =11 26gt11( 21-3+8)gt( -14+31-6)
12 SampleanswerAddandsubtractfromlefttoright-5+12+10-7=7+10-7=17-7=10
Independent Practice
13 a 5-1+6-1=9
b 9isapositivescoresoitisoverpar
c 9overparislessthan15overparYesCameronbeathisbestgolfscore
14 -6+14-11=-33feetunderground
15 TheCommutativePropertydoesnotapplytosubtraction3-6+5=2and3-5+6=4
16 a -350+275+70-50=-55Leersquosfinalscoreis-55points
b 45gt-55Barry
17 a 300to400
b 75+30-12+14-8+18-30=75+18+6-12=8787customersmustleavebetween400and500
18 100-18+22-53=51$51
19 45-17-22+18=24$24
20 Carlarsquosaccountdecreased$49-18+22-53=-49andLetarsquosaccountonlydecreased$21-17-22+18=-21Carlarsquosaccounthadthegreatestdecreaseinvalue
Focus on Higher Order Thinking
21 SampleanswerTimoweshisbrother1dollarHeborrows6moredollarsfromhisbrotherHepayshisbrotherback3dollarsHowmuchdoesTimstillowehisbrother-1-6+3=-4$4
22 Nothetotalamountshecouldpayherparentsis10+12+25=47and50-47=3Soshestillneeds$3
23 SampleanswerInthecaseinwhichthefirstnumberispositivethenthesumoftheabsolutevaluesoftheothertwonumbersmustbegreaterthanthevalueofthefirstnumberSampleexample13-5-10=-2ǀ 5ǀ+ǀ 10ǀ=15whichisgreaterthan13
MODULE 1
Ready to Go On
1 -8+( -6)=-14
2 -4+( -7)=-11
3 -9+( -12)=-21
CopyrightcopybyHoughtonMifflinHarcourt 4 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U1M01indd 4 103113 206 AM
4 5 + ( -2 )
ǀ 5 ǀ - ǀ -2 ǀ = 3
5 + ( -2 ) = 3
5 -8 + 4
ǀ -8 ǀ - ǀ 4 ǀ = 4
-8 + 4 = -4
6 15 + ( -8 )
ǀ 15 ǀ - ǀ -8 ǀ = 7
15 + ( -8 ) = 7
7 2 - 9 = 2 + ( -9 )
2 + ( -9 ) = -7
8 -3 - ( -4 ) = -3 + 4-3 + 4 = 1
9 11 - ( -12 ) = 11 + 12
11 + 12 = 23
10 -15 + 9 - 4 = -6 - 4
= -10
There are 10 fewer people on the bus
11 24 + 8 - 12 - 9 = 24 + 8 - ( 12 + 9 ) = 32 - 21
= 11
There are 11 cards left in the stack
12 Sample answer Tonya owes her sister $10 and
her friend $5 By how much will her savings change
after she pays them
-10 + ( -5 ) = -15 $15 decrease
Copyright copy by Houghton Mifflin Harcourt 5 All rights reserved
MODULE 2 Multiplying and Dividing Integers
Are You Ready
1 9 times 3 = 27
2 7 times 10 = 70
3 9 times 8 = 72
4 15 times 10 = 150
5 6 times 9 = 54
6 10 times 23 = 230
7 9 times 9 = 81
8 10 times 20 = 200
9 54 divide 9 = 6
10 42 divide 6 = 7
11 24 divide 3 = 8
12 64 divide 8 = 8
13 90 divide 10 = 9
14 56 divide 7 = 8
15 81 divide 9 = 9
16 110 divide 11 = 10
17 12 + 8 divide 212 + 4
16
18 15 - ( 4 + 3 ) times 2
15 - 7 times 2
15 - 14
1
19 18 - ( 8 - 5 ) 2
18 - ( 3 ) 2
18 - 9
9
20 6 + 7 times 3 - 5
6 + 21 - 5
27 - 5
22
21 9 + ( 2 2 + 3 ) 2 times 2
9 + ( 4 + 3 ) 2 times 2
9 + ( 7 ) 2 times 2
9 + 49 times 2
9 + 98
107
22 6 + 5 - 4 times 3 divide 2
6 + 5 - 12 divide 2
6 + 5 - 6
11 - 6
5
LESSON 21
Your Turn
4 Since the numbers have opposite signs the product
will be negative
ǀ -3 ǀ times ǀ 5 ǀ = 3 times 5 = 15
-3 ( 5 ) = -15
5 Since the numbers have the same sign the product
will be positive
ǀ -10 ǀ times ǀ -2 ǀ = 10 times 2 = 20
( -10 ) ( -2 ) = 20
6 One of the factors is 0 so the product is 0
0 ( -22 ) = 0
7 Since the numbers have the same sign the product
will be positive
8 ( 4 ) = 32
Guided Practice
1 -1 ( 9 ) = -9
2 14 ( -2 ) = -28
3 ( -9 ) ( -6 ) = 54
4 ( -2 ) ( 50 ) = -100
5 ( -4 ) ( 15 ) = -60
6 -18 ( 0 ) = 0
7 ( -7 ) ( -7 ) = 49
8 -15 ( 9 ) = -135
9 ( 8 ) ( -12 ) = -96
10 -3 ( -100 ) = 300
11 0 ( -153 ) = 0
12 -6 ( 32 ) = -192
13 7 ( -75 ) = -525 -$525
14 Start at zero and move 5 units to the left 3 times
3 ( -5 ) = -15 the team lost 15 yards
15 6 ( -2 ) = -12 -12degF
16 Multiply the absolute values of the integers If both
integers have the same sign the product is positive
If they have different signs the product is negative
Independent Practice
17 No her number line shows the correct result -6
but she modeled 2 ( -3 ) instead of -2 ( 3 )
18 2 ( -3 ) = -6 he went down 6 floors
19 5 ( -4 ) = -20 $20 decrease
20 Adam descended 5 feet a total of 5 times
5 ( -5 ) = -25 Adam is 25 feet below sea level
21 7 ( -6 ) = -42 the cost of the jeans decreased by
$42 over the 7 weeks
22 9 ( -6 ) = -54 -54 ( 2 ) = -108 Casey has $108
less in his savings
23 7 ( -8 ) = -56 7 ( -5 ) = -35
-56 + ( -35 ) = -91 The savings decreased by $91
24 Sample answer Dave plays a video game in which
he loses 20 points every time he misses a goal
He misses 8 goals 8 ( -20 ) = -160 he loses
160 points
Copyright copy by Houghton Mifflin Harcourt 6 All rights reserved
25 a 3 ( 3 ) ( -3 ) = 9 ( -3 ) = -27
b 3 ( -3 ) ( -3 ) = -9 ( -3 ) = 27
c -3 ( -3 ) ( -3 ) = 9 ( -3 ) = -27
d 3 ( 3 ) ( 3 ) ( -3 ) = 9 ( 3 ) ( -3 ) = 27 ( -3 ) = -81
e 3 ( 3 ) ( -3 ) ( -3 ) = 9 ( -3 ) ( -3 ) = -27 ( -3 ) = 81
f 3 ( -3 ) ( -3 ) ( -3 ) = -9 ( -3 ) ( -3 ) = 27 ( -3 ) = -81
g When a product of integers has an odd number of
negative factors like -3 ( -3 ) ( -3 ) = -27 and
3 ( 3 ) ( 3 ) ( -3 ) = -81 the sign of the product is
negative
When a product of integers has an even number
of negative factors like ( 3 ) ( -3 ) ( -3 ) = 27 and
3 ( 3 ) ( -3 ) ( -3 ) = 9 ( -3 ) ( -3 ) = 81 the sign of the
product is positive
Focus on Higher Order Thinking
26 -1 ( 3 ) ( 1 ) 1 ( -3 ) ( 1 ) -1 ( -3 ) ( -1 )
27 Unless one of the factors is 0 whenever the factors
have opposite signs the product will be less than or
equal to both of the two factors
28 The sign of the product is equal to the sign of the
integers The sign of the product of the first two
integers will always be positive Multiplying this
product by the remaining factor will make a positive
product if the factor is positive negative if it is
negative
LESSON 22
Your Turn
2 Since only the dividend is zero the quotient is 0
0 divide ( -6 ) = 0
3 Since the numbers have opposite signs the quotient
will be negative
38 divide ( -19 ) = -2
4 Since the numbers have the same sign the quotient
will be positive
-13 divide ( -1 ) = 13
5 Yolanda received the same number of penalties in
each game -25 divide ( -5 ) = 5 and -35 divide ( -7 ) = 5
Guided Practice
1 -14 ____ 2 = -7
2 21 divide ( -3 ) = -7
3 26 ____ -13
= -2
4 0 divide ( -4 ) = 0
5 -45 ____ -5 = 9
6 -30 divide ( 10 ) = -3
7 -11 ____ -1
= 11
8 -31 divide ( -31 ) = 1
9 0 ___ -7 = 0
10 -121 _____ -11
= 11
11 84 divide ( -7 ) = -12
12 500 ____ -25
= -20
13 -6 divide ( 0 ) = undefined any number divided by 0 is
undefined
14 -63 ____ -21
= 3
15 -40 divide ( 4 ) = -10 $10
16 -22 divide ( 11 ) = -2 2 points
17 -75 divide ( -15 ) = 5 5 targets
18 -99 divide ( -9 ) = 11 11 times
19 In both cases if the signs of the initial numbers are
the same the answer will be positive If the signs are
different the answer will be negative
Independent Practice
20 -24 divide ( 12 ) = -2 $2
21 Elisa made a greater number of withdrawals She
made -140 divide ( -20 ) = 7 withdrawals Francis made
-270 divide ( -45 ) = 6 withdrawals and 7 gt 6
22 a -2 - 10 = -12 the temperature decreased 12degF
b -12 divide ( 12 ) = -1 decreased by 1degF each hour
23 The first part the rate of change for the first part
is -200 ft _______ 10 min
= -20 ftmin and the rate of change for
the second part is -300 ft _______ 20 min
= -15 ftmin
20 ftmin gt 15 ftmin
24 Sample answer A football team lost 50 yards due to
5 penalties If the team lost the same number of
yards for each penalty what was the change in field
position for each penalty
25 Sample answer a = - 20 and b = 5 less than
-20 divide 5 = -4 and -20 times 5 = -100
-100 lt -4
26 True if the integers have the same sign the product
and quotient are positive if they have different signs
negative
27 False division by 0 is undefined for any dividend
Focus on Higher Order Thinking
28 a 100 divide 25 = 4 4 points
b -16 divide ( -4 ) = 4 Fred answered 4 questions
incorrectly
29 a divide ( -3 ) = 8
a = -24
8 divide b = -4
a divide b = -24 divide ( -2 ) = 12
Copyright copy by Houghton Mifflin Harcourt 7 All rights reserved
30 Dividing integers with the same sign results in a
positive number Since the original two integers are
negative the quotient is greater than both of these
integers
LESSON 23
Your Turn
1 Reggie earned 110 points
3 ( -30 ) + 200 = -90 + 200
= 110
2 -6 ( 13 ) - 21 = -78 - 21
= -99
4 ( -12 ) divide 6 + 2 = -2 + 2
= 0
5 -87 divide ( -3 ) -9 = 29 - 9
= 20
6 40 divide ( -5 ) + 30 = -8 + 30
= 22
7 -39 divide 3 -15 = -13 - 15
= -28
8 Amber moved 3 ( -3 ) + 5 = -4 or 4 places back
Will moved 2 ( -4 ) + 3 = -5 or 5 places back Will
moved further back
9 ( -10 ) divide 2 - 2 = -5 - 2 = -7
( -28 ) divide 4 + 1 = -7 + 1 = -6
10 42 divide ( -3 ) + 9 = -14 + 9 = -5
( -36 ) divide 9 - 2 = -4 - 2 = -6
Guided Practice
1 -6 ( -5 ) + 12 = 30 + 12
= 42
2 3 ( -6 ) - 3 = -18 - 3
= -21
3 -2 ( 8 ) + 7 = -16 + 7
= -9
4 4 ( -13 ) + 20 = -52 + 20
= -32
5 -4 ( 0 ) - 4 = 0 - 4
= -4
6 -3 ( -5 ) - 16 = 15 - 16
= -1
7 7 ( -5 ) + 20 = -35 + 20
= -15
15 dollars less
8 7 ( -10 ) + ( -100 ) = -70 + ( -100 )
= -170
170 fewer points
9 6 ( -4 ) + 10 = -24 + 10
= -14
Ned lost 14 points
10 4 ( -12 ) + 10 = -48 + 10
= -38
$38 less
11 -3 ( -2 ) + 3 = 6 + 3
= 9
3 ( -4 ) + 9 = -12 + 9
= -3
9 gt -3
-3 ( -2 ) + 3 gt 3 ( -4 ) + 9
12 -8 ( -2 ) -20 = 16 -20
= -4
3 ( -2 ) + 2 = - 6 + 2
= -4
-4 = -4
-8 ( -2 ) -20 = 3 ( -2 ) + 2
13 -7 ( 5 ) - 9 = -35 - 9
= -44
-3 ( 20 ) + 10 = -60 + 10
= -50
-44 gt -50
-7 ( 5 ) -9 gt -3 ( 20 ) + 10
14 -16 ( 0 ) -3 = 0 -3
= -3
-8 ( -2 ) -3 = 16 -3
= 13
-3 lt 13
-16 ( 0 ) -3 lt -8 ( -2 ) -3
15 A negative number usually represents a debt
payment or loss or a change that is a decrease
such as to a savings account
Independent Practice
16 -12 ( -3 ) + 7 = 36 + 7
= 43
17 -42 divide ( -6 ) + 5 -8 = 7 + 5 -8
= 12 -8
= 4
18 10 ( -60 ) -18 = -600 -18
= -618
19 ( -11 ) ( -7 ) + 5 - 82 = 77 + 5 - 82
= 82 - 82
= 0
20 35 divide ( -7 ) + 6 = -5 + 6
= 1
21 -13 ( -2 ) - 16 - 8 = 26 - 16 - 8
= 10 - 8
= 2
22 a 5 ( 2 ) -12 + 3 = 10 -12 + 3
= -2 + 3
= 1
b -3 ( 2 ) -1 + 6 + 7 = -6 -1 + 6 + 7
= -7 + 6 + 7
= -1 + 7
= 6
c Rose has more points than Lily so Rose won
the game
23 5 ( -4 ) -8 = -20 - 8 = -28
24 -36 divide ( -4 ) + 9 = 9 + 9 = 18
Copyright copy by Houghton Mifflin Harcourt 8 All rights reserved
25 a 4 ( -35 ) -9 = -140 -9
= -149
$149 less
b Yes $200 - $149 = $51 $51 gt $50 so Arleen
has enough money
26 a 2 ( -10 ) + 3 = -20 + 3= -17
b 7 + 2 + ( -7 ) = 2
c Warren since 2 is greater than -17
d Sample answer 2 of clubs 2 of spades
3 of spades king of diamonds 10 of clubs
7 of clubs
Focus on Higher Order Thinking
27 Sample answer Ann bought three shirts for $7 each
and a pair of pants for $10 Her mother gave her
$25 By how much did the amount of money Ann
had change
28 Disagree the quotient of two integers is positive if
the integers have the same sign So the first two
integers could have been negative integers
29 5 feet equals 60 inches so Lisa is holding the rock
60 inches above the waterrsquos surface The rock will
travel 4 times -5 = -20 inches or 20 inches below the
surface in 4 seconds 60 + 20 = 80 inches
MODULE 2
Ready to Go On
1 Since the numbers have opposite signs the product
will be negative
( -2 ) ( 3 ) = -6
2 Since the numbers have the same sign the product
will be positive
( -5 ) ( -7 ) = 35
3 Since the numbers have the opposite signs the
product will be negative
( 8 ) ( -11 ) = -88
4 ( -3 ) ( 2 ) ( -2 ) = ( -6 ) ( -2 ) = 12
5 5 ( -3 ) = -15 -15degC
6 -63 ____ 7 = -9
7 -15 ____ -3
= 5
8 0 ____ -15
= 0
9 96 ____ -12
= -8
10 -24 divide 6 = -4 -4 Ib
11 ( -4 ) ( 5 ) + 8 = -20 + 8
= -12
12 ( -3 ) ( -6 ) -7 = 18 -7
= 11
13 -27 ____ 9 - 11 = -3 - 11
= -14
14 -24 ____ -3
- ( -2 ) = 8 + 2
= 10
15 Sample answer Maurice lost 3 nickels in the laundry
and found 1 dime in the couch By how much did the
amount of money he had change
( -3 ) ( 5 ) + 10 = -15 + 10 = -5 He had $05 less
than before
Copyright copy by Houghton Mifflin Harcourt 9 All rights reserved
MODULE 3 Rational Numbers
Are You Ready
1 9 ___ 14
times 7 __ 6 =
3
2
9 ___ 14
times 7 __ 6 1
2
= 3 __ 4
2 3 __ 5 times 4 __
7 = 12 ___
35
3 11 ___ 8
times 10 ___ 33
= 1
4
11 ___ 8 times 10 ___
33 5
3
= 5 ___ 12
4 4 __ 9 times 3 =
3
4 __ 9 times 3 __
1 1
= 4 __ 3 or 1 1 __
3
5 1 __ 2 divide 1 __
4 = 1 __
2 times 4 __
1
=
1 1 __ 2 times 4 __
1 2
= 2 __ 1 = 2
6 3 __ 8 divide 13 ___
16 = 3 __
8 times 16 ___
13
= 1 3 __ 8 times 16 ___
13 2
= 6 ___ 13
7 2 __ 5 divide 14 ___
15 = 2 __
5 times 15 ___
14
= 1
1 2 __ 5 times 15 ___
14 3
7
= 3 __ 7
8 4 __ 9 divide 16 ___
27 = 4 __
9 times 27 ___
16
= 1
1 4 __ 9 times 27 ___
16 3
4
= 3 __ 4
9 3 __ 5 divide 5 __
6 = 3 __
5 times 6 __
5
= 18 ___ 25
10 1 __ 4 divide 23 ___
24 = 1 __
4 times 24 ___
23
= 1 1 __ 4 times 24 ___
23 6
= 6 ___ 23
11 6 divide 3 __ 5 = 6 __
1 times 5 __
3
= 2
6 __ 1 times 5 __
3 1
= 10 ___ 1 = 10
12 4 __ 5 divide 10 = 4 __
5 times 1 ___
10
= 2
4 __ 5 times 1 ___
10 5
= 2 ___ 25
13 21 - 6 divide 3
21 - 2
19
14 18 + ( 7 - 4 ) times 3
18 + 3 times 3
18 + 9
27
15 5 + ( 8 - 3 ) 2
5 + ( 5 ) 2
5 + 25
30
16 9 + 18 divide 3 + 10
9 + 6 + 10
15 + 10
25
17 60 - ( 3 - 1 ) 4 times 3
60 - ( 2 ) 4 times 3
60 - 16 times 3
60 - 48
12
18 10 - 16 divide 4 times 2 + 6
10 - 4 times 2 + 6
10 - 8 + 6
2 + 6
8
LESSON 31
Your Turn
0 _
571428
4 7 ⟌ _
40000000 Dividing into 40
_ -35
50
_ -49
10
_ -7
30
_ -28
20
_ -14
60
_ -56
40 Second appearance of 40
Because the number 40 repeats during the division
process the answer is a repeating decimal
-0 _
571428 or -0571428571428hellip
Copyright copy by Houghton Mifflin Harcourt 10 All rights reserved
0 _ 3
5 3 ⟌ _
100 Dividing into 10
_ -3
10 Second appearance of 10
Because the number 10 repeats during the division
process the answer is a repeating decimal 0 _ 3 or
0333hellip
045
6 20 ⟌ _
900
_ -8 0
1 00
_ -1 00
0
-045
7 -2 3 __ 4 = -thinsp 4 times 2 + 3
_________ 4 = -11 ____
4
275
4 ⟌ _
1100
_ -8
30
_ -28
20
_ -20
0
-275 terminating
8 7 1 __ 3 =
3 times 7 + 1 _________
3 = 22 ___
3
7 _ 3
3 ⟌ _
2200 Dividing into 10
_ -21
1 0 Second appearance of 10
Because the number 10 repeats during the division
process the answer is a repeating decimal 7 _ 3 or
7333hellip repeating
Guided Practice
06
1 5 ⟌ _
30
_ -3 0
0
06 terminating
089
2 100 ⟌ _
8900
_ -80 0
9 00
_ -9 00
0
-089 terminating
3 Simplify the fraction
4 ___ 12
= 4 times 1 _____ 4 times 3
= 1 __ 3
0 _ 3
3 ⟌ _
100 Dividing into 10
_ -3
10 Second appearance of 10
Because the number 10 repeats during the division
process the answer is a repeating decimal 0 _ 3 or
0333hellip repeating
0 _
25
4 99 ⟌ _
25000 Dividing into 25
_ -19 8
520
_ -495
25 Second appearance of 25
Because the number 25 repeats during the division
process the answer is a repeating decimal 0 _
25 or
02525hellip repeating
0 _ 7
5 9 ⟌ _
700 Dividing into 70
_ -63
70 Second appearance of 70
Because the number 70 repeats during the division
process the answer is a repeating decimal 0 _ 7 or
-0777hellip repeating
036
6 25 ⟌ _
900
_ -7 5
1 50
_ -1 50
0
-036 terminating
004
7 25 ⟌ _
100
_ -1 00
0
004 terminating
01420 _
45
8 176 ⟌ _
250000000
_ -17 6
7 40
_ -7 04
360
_ -352
80
_ -0
800 First appearance of 800
_ -704
960
_ -880
800 Second appearance of 800
Because the number 800 repeats during the
division process the answer is a repeating decimal
-01420 _
45 or -014204545hellip repeating
0012
9 1000 ⟌ _
12000
_ -10 00
2 000
_ -2 000
0
0012 terminating
Copyright copy by Houghton Mifflin Harcourt 11 All rights reserved
10 -11 1 __ 6 = -thinsp 6 times 11 + 1
_________ 6 = -67 ____
6
111 _ 6
6 ⟌ _
67000
_ -6
07
_ -6
1 0
_ -6
40 First appearance of 40
_ -36
40 Second appearance of 40
Because the number 40 repeats during the division
process the answer is a repeating decimal
- 67 ___ 6
-111 _ 6 or -111666hellip
11 2 9 ___ 10
= 10 times 2 + 9
__________ 10
= 29 ___ 10
29
10 ⟌ _
290
_ -20
9 0
_ -9 0
0
29 ___ 10
29
12 -8 23 ____ 100
= - 100 times 8 + 23
____________ 100
= -823 _____ 100
823
100 ⟌ _
82300
_ -800
23 0
_ -20 0
3 00
_ -3 00
0
-823 _____ 100
-823
13 7 3 ___ 15
= 15 times 7 + 3
__________ 15
= 108 ____ 15
72
15 ⟌ _
1080
_ -105
3 0
_ -3 0
0
108 ____ 15
72
14 54 3 ___ 11
= 11 times 54 + 3
__________ 11
= 597 ____ 11
54 _
27
11 ⟌ _
597000
_ -55
47
_ -44
30 First appearance of 30
_ -22
80
_ -77
30 Second appearance of 30
Because the number 30 repeats during the division
process the answer is a repeating decimal
597 ____ 11
54 _
27 or 542727hellip
15 -3 1 ___ 18
= -thinsp 18 times 3 + 1 __________
18 = -55 ____
18
30 _ 5
18 ⟌ _
55000
_ -54
1 0
_ -0
1 00 First appearance of 100
_ -90
100 Second appearance of 100
Because the number 100 repeats during the division
process the answer is a repeating decimal
-55 ____ 18
-30 _ 5 or -30555hellip
16 3 2 __ 3 =
3 times 3 + 2 _________
3 = 11 ___
3
3 _ 6
3 ⟌ _
1100
_ -9
2 0 First appearance of 20
_ -1 8
20 Second appearance of 20
Because the number 20 repeats during the division
process the answer is a repeating decimal
3 _ 6 or 3666hellip lbs of apples
17 -2 7 __ 8 = -
8 times 2 + 7 _________
8 = -23 ____
8
2875
8 ⟌ _
23000
_ -16
7 0
_ -6 4
60
_ -56
40
_ -40
0
-2875 lb
18 Disagree the definition of a rational number is a
number that can be written as the ratio of two
integers with a denominator not equal to zero and
3 ___ 47
is a well-defined ratio of two integers Tom did
not divide long enough to correctly determine that
the quotient is a repeating decimal
Copyright copy by Houghton Mifflin Harcourt 12 All rights reserved
Independent Practice
19 basketball players
_______________ football players
= 5 ___ 11
0 _
45
11 ⟌ _
5000 Dividing into 50
_ -4 4
60
_ -55
50 Second appearance of 50
Because the number 50 repeats during the division
process the answer is a repeating decimal
5 ___ 11
0 _
45 or 04545hellip repeating
20 hockey players
______________ lacrosse players
= 6 ___ 10
06
10 ⟌ _
60
_ -6 0
0
6 ___ 10
06 terminating
21 polo players
_____________ football players
= 4 ___ 11
036
11 ⟌ _
4000 Dividing into 40
_ -3 3
70
_ -66
40 Second appearance of 40
Because the number 40 repeats during the division
process the answer is a repeating decimal
4 ___ 11
0 _
36 or 03636hellip repeating
22 lacrosse players
______________ rugby players
= 10 ___ 15
= 5 times 2 _____ 5 times 3
= 2 __ 3
0 _ 6
3 ⟌ _
200 Dividing into 20
_ -1 8
20 Second appearances of 20
Because the number 20 repeats during the division
process the answer is a repeating decimal
10 ___ 15
0 _ 6 or 0666hellip repeating
23 football players
_____________ soccer players
= 11 ___ 11
= 1
11 ___ 11
1 terminating
24 Agree Sample answer There are 10 players on the
lacrosse team and dividing the number of any other
team by 10 will simply move the decimal point one
digit to the left Therefore the ratio of any team over
the lacrosse team will be a decimal that terminates
one place to the right of the decimal point
25 a -4 7 __ 8 = -thinsp 8 times 4 + 7
_________ 8 = - 39 ___
8
b 4875
8 ⟌ _
39000
_ -32
7 0
_ -6 4
60
_ -56
40
_ -40
0
-4875
c Sample answer 4 7 __ 8 is very close to 5 Therefore
You could estimate that the water level changes
by 5 inches per month The total change in the
water level at the end of the 3-month period
would be approximately -15 inches
26 integer terminating
27 Ben is taller because Benrsquos height of 5 5 ___ 16
is equal
to 85 ___ 16
or 53125 ft while Marcusrsquo height of 5 7 ___ 24
is
equal to 127 ____ 24
or 52916hellip ft
28 The first store has the better deal because they
offer 3 __ 4 or 075 of a bushel for $9 while the second
store offers only 2 __ 3 or 0666hellip of a bushel for $9
Focus on Higher Order Thinking
29 When the number 1 is the denominator in a fraction
its decimal form is simply the numerator In all other
cases concerning numbers 1 to 10 the division
process stops when either the remainder is 0 or
when the digits begin to repeat When the numbers
2 4 5 or 8 are in the denominator the decimal form
of a fraction will terminate When the numbers
3 6 7 or 9 are in the denominator the decimal form
of a fraction will be a repeating decimal
30 Julie made a higher score on her math test since
her math test score of 21 ___ 23
is equal to a repeating
decimal of approximately 0913 while her science
test score of 29 ___ 32
is equal to a terminating decimal of
090625
Sample answer The difference in scores cannot be
determined by simply comparing the numerators of
the two fractions because the denominators are not
the same For Julie to compare her scores she
needs to divide the denominators into their respec-
tive numerators until one of the quotients is found to
be greater than the other
31 No although the digits in the decimal appear to
follow a pattern a repeating decimal must have the
same combination of digits that repeat such as
0121212hellip
Copyright copy by Houghton Mifflin Harcourt 13 All rights reserved
LESSON 32
Your Turn
2
50 1 2 3 4
3 + 1 1 __ 2 = 4 1 __
2
3
0-7 -6 -5 -4 -3 -2 -1
-25 + ( -45 ) = -7
6
0 1 2-5-6-7-8 -4 -3-2-1
-8 + 5 = -3
7
10-1
1 __ 2 + ( - 3 __
4 ) = - 1 __
4
8
3 4 5 6 7 80 1 2-3-2-1
-1 + 7 = 6
9
3 4 50 1 2-5-4 -3-2-1
2 1 __ 2 + ( -2 1 __
2 ) = 0
10
3 4 50 1 2-5-4 -3-2-1
-45 + 45 = 0
11
1-1 0
3 __ 4 + ( - 3 __
4 ) = 0
The overall change is 0 cups
12 -15 + 35 + 2
-15 + 55
55 - 15
4
13 3 1 __ 4 + ( -2 ) + ( -2 1 __
4 )
3 1 __ 4 + ( -4 1 __
4 )
3 1 __ 4 - 4 1 __
4
-1
14 -275 + ( 325 ) + 5
-6 + 5
-1
15 15 + 8 + ( -3 )
23 + 3
20
Guided Practice
1
3 4 50 1 2-5-4 -3-2-1
-3 + ( -15 ) = -45
2
0 54321-5-4-3-2-1
15 + 35 = 5
3
0 105-1 -05
1 __ 4 + 1 __
2 = 3 __
4
4
0 54321-5-4-3-2-1
-1 1 __ 2 + ( -1 1 __
2 ) = -3
5
0 54321-5-4-3-2-1
3 + ( -5 ) = -2
6
0 54321-5-4-3-2-1
-15 + 4 = 25
7 -2150 + 2150 = 0 $0
8 -874 + 874 = 0 $0
9 275 + ( -2 ) + ( -525 )
275 + ( -725 )
- ( 725 - 275 )
-45
10 -3 + 1 1 __ 2 + 2 1 __
2 = -3 + 4 = 1
11 124 + 92 + 1
-124 + 102
- ( 124 - 102 )
-22
12 -12 + 8 +13
-12 + 21
21 - 12
9
13 45 + ( -12 ) + ( -45 )
45 + ( -45 ) + ( -12 )
0 + ( -12 )
-12
14 1 __ 4 + ( - 3 __
4 ) = - ( 3 __
4 - 1 __
4 ) = - 2 __
4 = - 1 __
2
Copyright copy by Houghton Mifflin Harcourt 14 All rights reserved
15 -4 1 __ 2 + 2 = - ( 4 1 __
2 - 2 ) = -2 1 __
2
16 -8 + ( -1 1 __ 8 ) = -9 1 __
8
17 Start at -4 and move 6 units to the right
The sum is 2
Independent Practice
18 The opposite of +19 is -19
19 -$225 + $1500 = $1500 - $225 = $1275
20 -3525 m + ( -85 ) = -4375 m
21 4 3 __ 4 mi + ( -3 1 __
4 mi ) = 1 2 __
4 mi = 1 1 __
2 mi
22 1635 m + ( -05 m ) = 163 m above sea level
23 30 + 15 - 25 = 45 - 25 = 20 pts
24 January
Income - Expenses
$1205 - $129060
- ( $129060 - $1205 ) -$8560
February
Income - Expenses
$1183 - $134544
-($134544 - $1183)
-$16244
Kameh lost $8560 in January and $16244 in
February
25 June
Income - Expenses
$2413 - $210623
$30677
July
Income - Expenses
$2260 - $195850
$30150
August
Income - Expenses
$2183 - $184512
$33788
Kameh gained $30677 in June $30150 in July and
$33788 in August
26 First sum all the values in the Income column Then
sum all the values in the Expenses column Subtract
the total expenses from the total income Finally add
the $250 profit from December (not shown in the
table) to find the total profit or loss of the bakery by
the end of August
Income = $1205 + $1183 + $1664 + $2413
$2260 + $2183 = $10908
Expenses = $129060 + $134544 + $1664 +$210623 + $195850 + $184512
= $1020989
Profit = $10908 - $1020989 + $250
= $94811
27 -2 is the opposite or additive inverse of 2
28 a 7 ( 10 ) + 3 ( -15 ) = 70 - 45 = 25 pts
b 2 ( 10 ) + 8 ( -15 ) = 20 - 120 = -100 pts
c 10 + 10 + 10 + 10 + 10 + ( ndash15 ) + ( ndash15 ) + ( ndash15 ) +
( ndash15 ) + ( ndash15 ) or 5 ( 10 ) + 5 ( ndash15 )
Focus on Higher Order Thinking
29 The sum of two negative rational numbers is always
negative The sum of a negative rational number and
a positive rational number is negative if the absolute
value of the negative number is greater than that of
the positive number
30 Sample answer The student might have subtracted
the absolute values of the numbers
31 Yes 55 and -55 are opposites and -23 and 23
are opposites so the expression [ 55 + ( -23 ) ] +
( -55 + 23 ) can be viewed as the sum of two
opposites which is always 0
LESSON 33
Your Turn
1
-9 -8 -7 -6 -5 -4
-65 - 2 = -85
2
42 30-1 1
1 1 __ 2 - 2 = - 1 __
2
3
-10-9 -8 -7 -6 -5 -4 -3 -2 -1 0
-225 - 55 = -775
6
1 2-1 0
025 - ( -150 ) = 175
7
1-1 0
- 1 __ 2 - ( - 3 __
4 ) = 1 __
4
Guided Practice
1
1312111098765 14 15
5 - ( -8 ) = 13
2
-9 -8 -7 -6 -5 -4 -3
3 1 __ 2 - 4 1 __
2 = -8
Copyright copy by Houghton Mifflin Harcourt 15 All rights reserved
3
-15 -13 -11 -9 -5-7
-7 - 4 = -11
4
-6 -5 -4 -3 -2 -1 0 1
-05 - 35 = -4
5 -14 - 22 = -36
6 -125 - ( -48 )
-125 + 48
- ( 125 - 48 )
-77
7 1 __ 3 - ( - 2 __
3 ) = 1 __
3 + 2 __
3 = 1
8 65 - ( -14 ) = 65 + 14 = 79
9 - 2 __ 9
- ( -3 )
- 2 __ 9
+ 3
3 - 2 __ 9
2 9 __ 9 - 2 __
9
2 7 __ 9
10 24 3 __ 8
- ( -54 1 __ 8 )
24 3 __ 8
+ 54 1 __ 8
78 4 __ 8
78 1 __ 2
11 -1 m + ( 105 m ) = -15 m
15 m below sea level
12 -12 1 __ 2 + ( -5 ) = -17 1 __
2
17 1 __ 2
or 175 yards
13 Change in height = Starting height - ending height
533 ft - ( -10 ft ) = 533 ft + 10 ft = 543 ft
14 -4500 + (-3015) = -7515 $7515
15 Explain that she is supposed to start at positive 4 on
the number line then move 12 places to the left
because she is subtracting a positive number She
will end on the number -8 which is the answer
Independent Practice
16 -126degC - 75degC = -201degC
17 -2565 ft - 165 ft + 1245 ft = -297 ft
The diver is 297 ft below the surface
18 -9500 ft - ( -26000 ft ) = 16500 ft
19 29035 ft - ( -36198 ft ) = 65233 ft
70000 ft - ( -26000 ft ) = 96000 ft
Mars has the greater difference by
96000 ft - ( 65233 ft ) = 30767 ft
20 a -5degF + 78degF - 32degF
b 78degF - 32degF
c -5degF + 78degF - 32degF 78degF - 5degF - 32degF 78degF - 37degF = 41degF 78degF - 32degF = 46degF
21 a -$1258 + ( -$3072 ) = -$4330
b -$4330 + ( -$25 ) = -$6830
c $6830 since -$6830 + $6830 = 0
22 a No 4 times 52 in = 208 in
b 208 in - 20 in = 08 in more needed
23 a 5 ft - 72 ft + 22 ft
b 5 ft - 72 ft + 22 ft
5 ft + 22 ft - 72 ft
72 ft - 72 ft
= 0 ft because he moved the same distance
backward and forward
24 a Yes
$425 + $089 + $1099
= $1613 lt $20
b $20 - $1613 = $387 left over
Focus on Higher Order Thinking
25 The Commutative Property of Addition (CPA) could
be used to simplify the two terms that already have
a common denominator first
- 7 ___ 16
- 1 __ 4 - 5 ___
16 = ( - 7 ___
16 ) + ( - 1 __
4 ) + ( - 5 ___
16 )
( - 7 ___ 16
) + ( - 5 ___ 16
) + ( - 1 __ 4 ) by CPA
( -7 + ( -5 ) __________
16 ) + ( - 1 __
4 )
( -12 ____ 16
) + ( - 1 __ 4 )
( - 4 times 3 _____ 4 times 4
) + ( - 1 __ 4 )
( - 3 __ 4 ) + ( - 1 __
4 )
( -3 + ( -1 ) __________
4 )
( -4 ___ 4 ) = -1
26 Lowest -225degF + ( -12degF ) = -345degFHighest -195degF + ( -12degF ) = -315degF
27 Sample answer Yes because both numbers are
rational numbers each can be written as the ratio of
two integers for example a __ b
and c __ d
Both fractions
could be given a common denominator and then
one could then be subtracted from the other The
result would be a fraction which is a rational number
28 No Sample answer It is possible for the
difference of two negative numbers to be negative
[ -4 - ( -1 ) = -3 ] but it is also possible for the
difference to be positive [ -5 - ( -8 ) = 3 ]
Copyright copy by Houghton Mifflin Harcourt 16 All rights reserved
LESSON 34
Your Turn
1
-8 -7 -6 -5 -2 -1 0-4 -3
2 ( -35 ) = -7
2
-2 -1 0 1 2 3 4-4 -3
-3 ( -125 ) = 375
4 ( - 3 __ 4 ) ( - 4 __
7 ) ( - 2 __
3 ) = -
13 times 41 times 2 __________ 14 times 7 times 31
= - 1 times 1 times 2 _________ 1 times 7 times 1
= - 2 __ 7
5 ( - 2 __ 3 ) ( - 3 __
4 ) ( 4 __
5 ) = 2 times 31 times 41
__________ 13 times 41 times 5
= 2 times 1 times 1 _________ 1 times 1 times 5
= 2 __ 5
6 ( 2 __ 3 ) ( - 9 ___
10 ) ( 5 __
6 ) = -
12 times 93 times 51
____________ 13 times 210 times 63
= - 1 times 31 times 1 __________ 1 times 2 times 31
= - 1 __ 2
Guided Practice
1
-5 -2 -1 0-4 -3
5 ( - 2 __ 3 ) = 5 __
1 times ( - 2 __
3 )
= - 5 times 2 _____ 1 times 3
= - 10 ___ 3
= -3 1 __ 3
2
-1 -05 0-2 -15
3 ( - 1 __ 4 ) = 3 __
1 times - 1 __
4
= - 3 times 1 _____ 1 times 4
= - 3 __ 4
3
0 1 2-2 -1
-3 ( - 4 __ 7 ) = 3 __
1 times 4 __
7
= 3 times 4 _____ 1 times 7
= 12 ___ 7
= 1 5 __ 7
4
-2 -1 0 1 2 3 4-4 -3
- 3 __ 4 ( -4 ) = 3 __
4 times 4 __
1
= 3 times 41
______ 14 times 1
= 3 times 1 _____ 1 times 1
= 3 __ 1
= 3
5 4 ( -3 ) = -12
6 -18 ( 5 ) = -9
7 -2 ( -34 ) = 68
8 054 ( 8 ) = 432
9 -5 ( -12 ) = 6
10 -24 ( 3 ) = -72
11 1 __ 2 times 2 __
3 times 3 __
4 = ( 1 times 21
______ 12 times 3
) ( 3 __ 4 )
= ( 1 __ 3 ) ( 3 __
4 )
= 1
1 __ 3 times 3 __
4 1
= 1 __ 4
12 - 4 __ 7 ( -thinsp 3 __
5 ) ( - 7 __
3 ) = ( - 4 times 3 _____
7 times 5 ) ( - 7 __
3 )
= 12 ___ 35
( - 7 __ 3 )
= - 4
5 12 times 7 ______ 35 times 3
1
1
= - 4 times 1 _____ 5 times 1
= - 4 __ 5
13 ( - 1 __ 8 ) times 5 times 2 __
3 = ( - 1 __
8 ) times 5 __
1 times 2 __
3
= - 1 times 5 times 21
__________ 48 times 1 times 3
= - 1 times 5 times 1 _________ 4 times 1 times 3
= - 5 ___ 12
Copyright copy by Houghton Mifflin Harcourt 17 All rights reserved
14 ( - 2 __ 3
) ( 1 __ 2 ) ( - 6 __
7 ) = 2 times 1 times 62
__________ 13 times 21 times 7
= 1 times 1 times 2 _________ 1 times 1 times 7
= 2 __ 7
15 4 ( -350 ) = -14 or a $14 change in price
16 18 ( -100 ) = -1800 or a $1800 change
17 Sample answer Count the number of times there is
a negative sign If there are an even number of
negative signs then the final product will be positive
If there is an odd number of negative signs then the
final product will be negative
Independent Practice
18 a 6 ( -1998 ) Note that the change in her bank
account balance does not depend on the initial
amount
b 200 + 6 ( -1998 )
= 200 - 11988
= 8012 $8012
19 Sample answer Start at 0 then move 15 units to
the left (because 15 is negative in this case) 4 times
You are now on -6 Then because 4 is negative in
this case we want to move to the opposite of -6
which is 6
20 8 ( -3 1 __ 4 ) = -8 ( 13 ___
4 )
= - 1
8 __ 1 times 13 ___
4 1
= - 2 times 13 ______ 1 times 1
= - 26 ___ 1
-26 min At the same rate the watch will be
26 minutes behind after 8 weeks
21 3 ( -325 ) = -975 ft The change in depth is -975 ft
Therefore the submarine will be 975 below sea level
(below the surface)
22 5 + ( -3 ) ( 15 )
= 5 + ( -45 )
= 05 cups left
23 Matthew is incorrect Sample answer Matthew
should have said that multiplying by two negatives
is like multiplying the opposite of a positive twice
The opposite of a positive twice brings you back to
a positive
24 5 ( -15 ) = -75 min Therefore she will be late by
75 minutes or 1 hour and 15 minutes
25 Total score is
2 times ( 6 ) + 16 times ( 05 )
+ 7 times ( -05 ) + 2 times ( -15 )
= 12 + 8 - 35 - 3
= 20 - 65
= 135 pts
Focus on Higher Order Thinking
26 Temperature at 5 kilometers
= Temp at ground level + change in temp
= 12 + 5 ( -68 )
= 12 + ( -34 )
= -22degC
27 a b c d
+ + + +
+ + - +
+ - + +
- + + +
- - - +
- - + -
- + - -
+ - - -
28 If the product of two numbers is positive then the two
numbers must have the same sign either they are
both positive or both negative If the sum is negative
then at least one of the numbers must be negative
Therefore the two integers that add to -7 and multiply
to 12 must both be negative The negative paired
factors of 12 are -1 and -12 -2 and -6 and -3
and -4 Of those choices only -3 and -4 add to -7
LESSON 35
Your Turn
3 28 ___ -4
= - 28 ___ 4 = -07
4 -664 ______ -04
= 664 ____ 04
= 166
5 - 55 ___ 05
= - 55 ___ 5 = -11
6 -4256 _______ 112
= -38
The divers change in elevation was -38 feet
per minute
7 - 5 __
8 ___
- 6 __ 7 = - 5 __
8 divide - 6 __
7
= - 5 __ 8 times - 7 __
6
= 35 ___ 48
8 - 5 ___
12 ____
2 __ 3 = - 5 ___
12 divide 2 __
3
= - 5 ___ 12
times 3 __ 2
= - 15 ___ 24
= - 5 __ 8
Copyright copy by Houghton Mifflin Harcourt 18 All rights reserved
9 -4__5
___1__2 =-4__5divide1__
2
=-4__5times2__1
=-8__5
=-13__5
Guided Practice
1 072_____-09=-72___
9 =-08
2 -1__5
___7__5 =-1__
15times5
1__
7=-1times1_____
1times7=-1__7
3 56___-7=-56___7=-8
4 251____4 divide(-3__
8)=251____
4 times-8__
3
=-251times82________
14times3
=-251times2_______1times3
=-502____3
5 75____-1__5
=-75___1times5__
1=-75times5______
1times1=-375
6 -91____-13=91___
13=7
7 -3__7
___9__4 =-
13__7times4__93
=-1times4_____7times3
=-4___21
8 - 12____003
=-1200_____
3 =-400
9 =changeinwaterlevel_________________
changeindays
=-35L______4day
=-0875 L____day
or-0875Lperday
10 =totalchangeinprice_________________
changeindays
=-$4575________5day
=-$915perdayonaverage
11 totalchangeinaltitude___________________
numberofminutes
=-044mi________08min
=-44mi______8min
=-055mileperminute
12 FirstfindthesignofthenumeratorwhichisnegativeNextfindthesignofthedenominatorwhichisnegativeThereforethequotientwillbepositivebecausethenumeratoranddenominatorbothhavethesamesign
Independent Practice
13 5___-2__
8=-5__
1times8__
24
1=-5times4_____
1times1=-20
14 51__3divide(-11__
2)
=-3times5+1_________3 divide2times1+1_________
2
=-16___3divide3__
2
=-16___3times2__
3
=-16times2______3times3
=-32___9
15 -120_____-6 =120____
6 =20
16 -4__5
___-2__
3=
24__5times3__
21=2times3_____
5times1=6__
5
17 103divide(-103)=-103____1 times 1____
103
=-103times1________1times103
=-103____103
=-103____103
=-01
18 -04_____80
=-04___80
=-0005
19 1divide9__5=1__
1times5__
9=5__
9
20 -1___4 ___
23___24
=-1__
14times246
___23
=-1times6______1times23
=-6___23
21 -1035_______-23 =1035_____
23 =45
22 totalhours_____________numberofdays
= 21h______7days
=3 h____day
totaltimelost3 h____day
times3days=9hours
Alexusuallyruns21hoursperweeksodivideby7tofindthatheruns3hoursperdaySinceheisunabletorunfor3dayshistimeisdecreasedby9hoursor-9
23 totalchangeinyards
_________________numberofruns
=-4times15+3___________4 times1__
9
yd___run
=-763___4 times1__
91yd
___run
=-153__
4yd______
9runs
=-153__4times1__
9
yd___run
=-7__4or-13__
4yardsperrun
CopyrightcopybyHoughtonMifflinHarcourt 19 Allrightsreserved
DO NOT EDIT--Changes must be made through File info CorrectionKey=B
7_MCABESK207233_U1M03indd 19 103113 759 PM
24 -121degC + ( -78degC ) + ( -143degC ) + ( -72degC )
_____________________________________ 4
= 414degC ______ 4
= -1035degC per day
25 a total profit
_____________ number of days
= $1750
______ 7 days
= $250 per day
b $150
_____ day
times 7 days = $1050
c total change
_____________ number of days
= - $490
______ 7 days
= -$70 per day
26 total meters descended ___________________ number of seconds
= 996 m ______ 12 s
= 83 ms
27 When converting the division equation into a
multiplication problem he forgot to multiply by the
reciprocal and instead multiplied by the fraction in
the denominator The correct answer is given by
- 3 __
4 ___
4 __ 3
= - 3 __
4 times 3 __
4 = - 9 ___
16
28 -37 m _______ year times ( 2012 ndash 1995 ) years
= -37 m _______ year times 17 years
= -629 m
Focus on Higher Order Thinking
29 Sample answer The average change in temperature
per day would be given by -85 divide 15 if the
temperature were to drop of 85degF over 15 days
-85degF divide 15 d
= - 1785 ____ 315
degF __ d
= - 17 ___ 3 degF __
d or -5 2 __
3 degF __
d asymp -567 degF __
d
On average the temperature changed by -567degF
every day
30 Yes By definition the result of dividing an integer by
a non-zero integer is a rational number
31 Yes The result of dividing an integer by a non-zero
integer always results in a rational number by
definition
LESSON 36
Your Turn
1 Find the total commercial time
3 times 2 1 __ 2 = 7 1 __
2
Find the total entertainment time
30 - 7 1 __ 2 = 22 1 __
2
Find the length of each entertainment segment
22 1 __ 2 divide 4 = 5 5 __
8
Each entertainment segment is 5 5 __ 8 minutes long
2 Find the number of cups of sugar in the bag
454 divide 48 asymp 95
Find the number of 3 __ 4 -cup portions in the bag
95 divide 075 asymp 127
12 batches can be made from the bag of sugar
Find the cost of 1 batch
349 divide 12 asymp 029
The cost of the sugar is $029 per batch
3 Convert the percent to a decimal
12 3 __ 5 = 126
= 0126
Find the worth after 1 year
750 times 0126 = 945
750 + 945 = 8445
Find the worth after 2 years
8445 times 0126 asymp 10641
8445 + 10641 = 95091
Find the worth after 3 years
95091 times 0126 asymp 11981
95091 + 11981 = 107072
The stock is worth $107072
Guided Practice
1 45h times 3 1 __ 5 or 32 miles per hour = 144 miles
144 miles divide 3 3 __ 5 or 36 miles per hour = 4 hours
2 2568 inches times -002375 asymp -061 inches
2568 inches - 061 asymp 2507 inches
3 Sample answer Using a calculator to solve a
problem that involves complicated arithmetic can
help you avoid errors It can also help you to check
solutions to any problems you solved by hand
Independent Practice
4 Find the total weight
78 times 3 = 234
Find the weight each climber carries
234 divide 4 = 585
Each climber carries 585 kg
Copyright copy by Houghton Mifflin Harcourt 20 All rights reserved
5 Find the available width on the page
12 - 3 1 __ 2 = 8 1 __
2
Find half the width
8 1 __ 2 divide 2 = 4 1 __
4
He should put the picture 4 1 __ 4 inches from each side
of the page
6 Find the amount of cereal needed for all the children
11 times 1 __ 3 = 3 2 __
3
10 times 3 __ 4 = 7 1 __
2
3 2 __ 3 + 7 1 __
2 = 11 1 __
6
Compare the total needed with the amount in the
box
11 1 __ 6 lt 12
Yes there is enough Oaties for all the children The
amount needed is 11 1 __ 6 cups and that is less than the
amount in the box 12 cups
7 Find half of the distance that the referee walked
41 3 __ 4 divide 2 = 20 7 __
8
Find how far that distance is from the goal line
50 - 20 7 __ 8 = 29 1 __
8
The referee is 29 1 __ 8 feet from the nearest goal line
8 Donovanrsquos score was 39 ___ 50
= 78 Marcirsquos score was
( 78 + 10 ) = 88
9 Find the number Marci answered correctly
88 = 88 ____ 100
= 44 ___ 50
Find how many more that Marci answered than
Donovan
44 - 39 = 5
Marcie answered 5 more questions correctly than
Donovan
10 Sample answer Donovan got about 40 out of 50
questions right or about 80 Since Marci scored
10 more that is about 90 90 times 50 is 45 So
Marci answered about 45 - 40 or 5 more questions
correctly than Donovan
11 Yes -075 is a reasonable estimate
19 ___ 37
is about 1 __ 2 and 143 is about 15 and
15 times ( - 1 __ 2 ) = -075
12 Sample answer approximately -07343 Use a
calculator Divide -19 by 37 multiply the quotient by
143 then round the product
13 Sample answer Yes -07343 asymp - 075
Focus on Higher Order Thinking
14 Find the time of the descent
-79 9 ___ 10
divide ( -188 ) = 425
Find the time for the ascent
19 1 __ 8 - 1275 - 425 = 2 1 __
8
Find the distance of the ascent
-28 9 ___ 10
- ( -79 9 ___ 10
) = 51
Find the rate of the ascent
51 divide 2 1 __ 8 = 24
The diverrsquos rate of change in elevation during the
ascent was 24 ftmin
15 Sample answer
(1) Convert the mixed number 27 3 __ 5 to the decimal
276 find the sum of 276 and 159 then multiply
the result by 037
(2) Convert the mixed number 27 3 __ 5 to the decimal
276 Then use the Distributive Property so that
(276 + 159)037 = (276)(037) + (159)(037)
Multiply both 276 and 159 by 037 and add the
products I would use the first method because
there are fewer steps and so fewer chances to
make errors
16 Sample answer You need to know how many
gallons of paint you need to paint a wall Measure
the length and width of the wall with a yardstick
then find the area Use the calculator to divide the
area by the number of square feet a gallon of the
paint covers Round up rather than down to the
nearest gallon so you have enough paint
MODULE 3
Ready to Go On
1 4 1 __ 5 =
5 times 4 + 1 _________
5 = 21 ___
5
42
5 ⟌ _
210
_ -20
1 0
_ -1 0
0
42
Copyright copy by Houghton Mifflin Harcourt 21 All rights reserved
2 12 14 ___ 15
= 15 times 12 + 14
___________ 15
= 194 ____ 15
129 _ 3
15 ⟌ _
194000
_ -15
44
_ -30
14 0
_ -13 5
50 first 50
_ -45
50 second 50
Because the number 50 repeats during the division
process the answer is a repeating decimal
129 _ 3 or 12933
3 5 5 ___ 32
= 32 times 5 + 5
__________ 32
= 165 ____ 32
515625
32 ⟌ _
16500000
_ -160
5 0
_ -3 2
1 80
_ -1 60
200
_ -192
80
_ -64
160
_ -160
0
515625
4 45 + 71 = 116
5 5 1 __ 6 + ( -3 5 __
6 ) = 4
6+1 ____
6 -3 5 __
6
= 1 2 __ 6
= 1 1 __ 3
6 - 1 __ 8 -6 7 __
8 = - 1 __
8 + ( -6 7 __
8 )
= -6 8 __ 8
= -7
7 142 - ( -49 ) = 142 + 49
= 191
8 -4 ( 7 ___ 10
) = - 4 __ 1 times 7 ___
10
= - 24 times 7 _______ 1 times 105
= - 2 times 7 _____ 1 times 5
= - 14 ___ 5 or -2 4 __
5
9 -32 ( -56 ) ( 4 ) = 32 times 56 times 4
= 7168
10 - 19 ___ 2 divide 38 ___
7 = -
119 times 7 _______ 2 times 382
= - 1 times 7 _____ 2 times 2
= - 7 __ 4
11 -3201 _______ -33
= 3201 _____ 33
97
33 ⟌ _
3201
_ -297
23 1
_ -23 1
0
97
12 Add the initial stock price with the increase from the
second day
$8360 + $1535 = $9895
Convert the percent decrease to a decimal
-4 3 __ 4 = -475 or -00475
Multiply the price on the second day times the
percent decrease and then subtract the result from
the price on the second day to find the final stock
price
$9895 times -00475 asymp -$47
$9895 - $47 = $9425
The final stock price is $9425 Yes this is
reasonable price on day 1 asymp $85 price on day
2 asymp $100 So the price on day 3 asymp $95
13 Sample answer You can use negative numbers to
represent temperatures below zero or decreases in
prices
Copyright copy by Houghton Mifflin Harcourt 22 All rights reserved
MODULE 4 Ratios and Proportionality
Are You Ready
1 3 __ 4 divide 4 __
5 = 3 __
4 times 5 __
4
= 15 ___ 16
2 5 __ 9 divide 10 ___
11 = 5 __
9 times 11 ___
10
= 1
5 __ 9 times 11 ___
10 2
= 11 ___ 18
3 3 __ 8 divide 1 __
2 = 3 __
8 times 2 __
1
= 4
3 __ 8 times 2 __
1 1
= 3 __ 4
4 16 ___ 21
divide 8 __ 9 = 16 ___
21 times 9 __
8
=thinsp 2
7 16 ___ 21
times 9 __ 8 3
1
= 6 __ 7
5 B ( -4 1 )
6 C ( 3 0 )
7 D ( 5 4 )
8 E ( -2 -2 )
9 F ( 0 0 )
10 G ( 0 -4 )
LESSON 41
Your Turn
3 1 __ 6 acre divide ( 1 __
4 hour ) = 1 __
6 times 4 __
1
= 3
1 times 4 _____ 6 times 1
2
= 1 times 2 _____ 3 times 1
= 2 __ 3 acre per hour
4 3 cups divide ( 3 __ 4 cups ) = 3 __
1 divide 3 __
4
= 3 __ 1 times 4 __
3
= 1
3 times 4 _____ 1 times 3
1
= 1 times 4 _____ 1 times 1
= 4 cups
5 Jaylan 3 __ 4 divide 1 __
5 = 3 __
4 times 5 __
1 = 15 ___
4 = 3 3 __
4
Wanchen 2 __ 3 divide 1 __
6 = 2 ___
1 3 times 6
2 __
1 = 4 __
1 = 4
Jaylanrsquos unit rate is 3 3 __ 4 cups of water per cup of lime
juice Wanchenrsquos unit rate is 4 cups of water per cup
of lime juice Wanchenrsquos limeade has a weaker lime
flavor because 4 gt 3 3 __ 4 and the limeade with a
greater ratio of water to lime juice will have a weaker
flavor
Guided Practice
1
Distance (mi) 8 1 __ 2 17 25 1 __
2 34 42 1 __
2
Time (h) 1 __ 2 1 1 1 __
2 2 2 1 __
2
2 3 1 __ 2 miles divide ( 1 1 __
4 hours ) = 7 __
2 divide 5 __
4 mi ___ h
= 7 times 4 _____ 2 times 5
= 1 7 times 4 _____ 2 times 5
2
= 7 times 2 _____ 1 times 5
= 14 ___ 5 mi ___
h
= 2 4 __ 5 miles per hour
3 5 __ 8 page divide ( 2 __
3 minute ) = 5 __
8 times 3 __
2
= 15 ___ 16
page per minute
4 1 __ 6 foot divide ( 1 __
3 hour ) = 1 __
6 times 3 __
1
= 2 1 times 3 _____ 6 times 1
1
= 1 times 1 _____ 2 times 1
= 1 __ 2 foot per hour
5 5 __ 8 sq ft divide ( 1 __
4 hour ) = 5 __
8 times 4 __
1
= 2 5 times 4 _____ 8 times 1
1
= 5 times 1 _____ 2 times 1
= 5 __ 2 or 2 1 __
2 square feet per hour
Solutions KeyRatios and Proportional Relationships
UNIT
2
Copyright copy by Houghton Mifflin Harcourt 23 All rights reserved
6 240 milligrams divide ( 1 __ 3 pickle ) = 240 ____
1 divide 1 __
3
= 240 ____ 1 times 3 __
1
= 720 ____ 1
Brand Arsquos rate is 720 mg per pickle
325 milligrams divide ( 1 __ 2 pickle ) = 325 ____
1 divide 1 __
2
= 325 ____ 1 times 2 __
1
= 650 ____ 1
Brand Brsquos rate is 650 milligrams per pickle and is
therefore lower than Brand A
7 The unit rate for Ingredient C is
1 __ 4 cup divide ( 2 __
3 serving ) = 1 __
4 times 3 __
2
= 3 __ 8
cup _______
serving
The unit rate for Ingredient D is
1 __ 3 cup divide ( 3 __
4 serving ) = 1 __
3 times 4 __
3
= 4 __ 9
cup _______
serving
To compare 3 __ 8 to 4 __
9 find the least common
denominator of 8 and 9 so that 3 __ 8 = 27 ___
72 and 4 __
9 = 32 ___
72
Therefore ingredient Crsquos unit rate is lower
8 Divide the number in the numerator by the number
in the denominator Write the result with the units of
the rate
For example 1 mile ______
1 __ 2 hour
= 1 __
1 __ 2 = 2 miles per hour
Independent Practice
9 a The unit rate in dollars per hour for On Call is
$10 divide ( 35 hours ) = 10 ___ 35
$ __
h asymp $286 per hour
The unit rate in dollars per hour for Talk Time is
$125 divide ( 1 __ 2 hours ) = 125 ____
05 $ __
h asymp $250 per hour
b Talk Time offers the better deal because its rate in
dollars per hour is lower
c To convert dollars per minute to dollars per hour
multiply by 60
$005 divide ( 1 minute )
= 005 ____ 1
$ ____
min times 60 min ______
1 h
= $3 per hour
d $3 per hour is more expensive than either On Call
or Talk Time so it is not a better deal than either
one
10 a Sample answer 1 __ 2 cup dried fruit to 1 __
8 cup
sunflower seeds in a granola recipe
b The ratio would not change if the recipe were
tripled because both numbers in the ratio would
be multiplied by the same number and therefore
the ratio would still be equivalent to what it was
originally
c 1 __ 2 divide 1 __
8 = 1 ___
1 2 times 8
4 __
1 = 4 __
1 = 4
Sample answer 4 cups dried fruit per 1 cup
sunflower seeds
11 10 songs
____________ 2 commercials
= 5 songs ____________
1 commercials
12 a Terrancersquos rate
6 mi divide ( 1 __ 2 h ) = 6 __
1 times 2 __
1
= 12 miles per hour
Jessersquos rate
2 mi divide ( 15 min ) = 2 __ 1 divide 1 __
4
= 2 __ 1 times 4 __
1 mi ___ h
= 8 miles per hour
b Terrance
50 mi divide ( 12 mi ___ h ) = 50 ___
1 times 1 ___
12
= 50 ___ 12
h
= 4 1 __ 6 h
= 4 10 ___ 60
h
= 4 hours and 10 minutes
Jesse
50 mi divide ( 8 mi ___ h ) = 50 ___
1 times 1 __
8
= 50 ___ 8 h
= 6 1 __ 4 h
= 6 15 ___ 60
h
= 6 hours and 15 minutes
c 8 mi divide ( 45 min ) = 8 __ 1 divide 3 __
4
= 8 __ 1 times 4 __
3
= 32 ___ 3
= 10 2 __ 3 miles per hour
Sandrarsquos unit rate is greater than Jessersquos but
lower than Terrancersquos so she runs slower than
Terrance but faster than Jesse
13 1 ___ 10
h = 6 ___ 60
h = 6 min
300 words _________ 6 min
= 50 words per min
1 ___ 12
h = 5 ___ 60
h = 5 min
300 words _________ 5 min
= 60 words per min
Faster Eli typed 50 words per minute in his first test
and 60 words per minute in his second test
Copyright copy by Houghton Mifflin Harcourt 24 All rights reserved
Focus on Higher Order Thinking
14 a For the 10-pack of 21 ounce bars
$1537 divide 10 bars asymp $154 per bar
For the 12-pack of 14 ounce bars
$1535 divide 12 bars asymp $128 per bar
The 12-pack has the better price per bar
b For the 10-pack
$1537 divide ( 10 times 21 oz ) = 1537 divide 21
asymp $073 per ounce
For the 12-pack
$1535 divide ( 12 times 14 oz ) = 1535 divide 168
asymp $091 per ounce
The 10-pack has a better price per ounce
c Sample answer Since I always eat them one bar
at a time the 12-pack is the better choice
15 Yes Half a room in half a day corresponds to a unit
rate of 1 __ 2 room divide ( 1 __
2 day ) = 1 room _____
day so at the same
rate the painter could paint 7 rooms in 7 days
16 Sample answer Take the reciprocal of the rate For
example a rate of 7 gallons per hour is equal to
1 hour per 7 gallons
LESSON 42
Your Turn
3 No the rates are not equal and therefore her speed
was not constant
4 Since the ratio of students to adults is constant the
relationship between them is proportional
students ________ adults
= 12 ___ 1 = 36 ___
3 = 60 ___
5 = 12 students per adult
If s = the number of students and a = the number
of adults then a = 1 ___ 12
s or s = 12a
Guided Practice
1 45 ___ 1 = 45 90 ___
2 = 45 135 ____
3 = 45 180 ____
4 = 45
The relationship is proportional
2 k = y __ x = 10 ___
2 = 5 y = 5x
3 k = y __ x = 2 __
8 = 1 __
4 y = 1 __
4 x
4 With the equation y = kx where k is the constant
of proportionality
Independent Practice
5 k = y __ x = 74 ___
4 = 1850 y = 1850x
6 $1099
_______ 05 days
= $2198 per day
7 Rent-All because it has the lowest price per day
($1850)
8 100 ft _____ 08 s
= 1000 _____ 8 ft __ s = 125 ft __ s
500 ft _____ 31 s
= 5000 _____ 31
ft __ s asymp 1613 ft __ s
1875 ft ______ 15 s
= 1875 ______ 15
ft __ s asymp 125 ft __ s
No Emtiaz assumed the relationship is proportional
but it is not The rate of change is not constant and
so his answer is not reasonable
9 $3125
______ 5 h
= $625 per hour and $5000
______ 8 h
= $625 per
hour Because the two unit rates are the same the
relationship between charge and time is proportional
10 The constant rate of change in this context means
that Steven charges $625 per hour
11 y = $625x where x is the number of hours Steven
babysits and y is the amount Steven charges
12 y = $625 ( 3 ) = $1875
13 300 ft _____ 2 min
= 6750
_____ 45
= 150 feet per minute
150 ft _____ min
times 60 min ______ 1 h
= 9000 feet per hour
14 y = 150x
15 Sample answer Feet per minute A submarine may
stay submerged for hours but it would not dive for
hours
Focus on Higher Order Thinking
16 Yes because there is a proportional relationship
so the distance and the time would increase by the
same factor
17 Sample answer Yes Even though the rates in the
table are not constant per ear of corn due to
rounding there is a constant rate for every 3 ears
of corn
LESSON 43
Your Turn
1 No because 11 ___ 1 ne 16 ___
2 Also the line drawn through
the points does not go through the origin
5 a The point ( 4 60 ) represents that the bicyclist can
ride a distance 60 miles in 4 hours
b k = 60 mi _____ 4 h
= 15 mi ___ h
c y = 15x where x is time in hours and y is
distance in miles
Guided Practice
1
Time (h) 3 5 9 10
Pages 195 325 585 650
Proportional the rate is a constant 65 pages
per hour
2
Time (h) 2 3 5 8
Earnings 15 2250 3750 60
Proportional the rate of is a constant $750 per hour
Copyright copy by Houghton Mifflin Harcourt 25 All rights reserved
3 Not proportional the relationship is linear but a line
drawn connecting the points will not pass through
the origin of ( 0 0 )
4 Proportional a line can be drawn that passes
through the points and also the origin of ( 0 0 )
5 k = 28 ft ____ 8 s
= 7 __ 2 ft __ s = 35 ft __ s y = 7 __
2 x or y = 35x where
x = time in seconds and y = height in feet
6 k = $2 ______
8 items = 1 __
4
$ _____
items = 025
$ _____
items so y = 1 __
4 x or
y = 025x where x = number of items and
y = cost in dollars
7 The graph is a straight line passing through the
origin
Independent Practice
8 It is the distance ( 0 miles ) that each horse runs in
0 minutes
9 Horse A runs 1 mile in 4 minutes
Horse B runs 1 mile in 25 minutes
10 For Horse A y = 1 __ 4 x
For Horse B y = 1 ___ 25
x or 2 __ 5 x
11 If x is time in minutes and y is distance in miles in
12 minutes Horse A will run 3 miles or 1 __ 4 ( 12 ) = 3
and Horse B will run 48 miles or 2 __ 5 ( 12 ) = 24 ___
5 = 48
12 Students may draw any straight line with a slope
steeper than 2 __ 5 that starts at the origin of ( 0 0 ) An
example is given below
2
2
4
6
8
10
4 6 8 10Time (min)
Dis
tanc
e (m
i)
A
B
O
13 Yes if the train is traveling at a constant speed the
ratio of miles traveled to time in hours will be
constant and therefore a graph comparing miles to
hours will form a straight line that passes through
the origin of ( 0 0 )
14 Sample answer When comparing relationships that
may be easier to observe on a graph than in an
equation
15 a
2
8
16
24
32
40
4 6 8 10DVDs
Cost
($)
O
b Sample answer The graph will pass through the
point ( 4 20 ) This point shows that four DVDs will
cost $20
16 The graph passes through the point ( 4 8 ) so
Glenda swam 8 feet in 4 seconds
17 Yes The graph is linear and passes through the
origin and therefore the rate of distance to time is
proportional at each point on the line
18 k = 8 ft ___ 4 s
= 2 ft __ s so y = 2x where x is time in
seconds and y is distance swam in feet It would
take 22 minutes to swim 1 __ 2 mile at this rate
Focus on Higher Order Thinking
19 Divide the second coordinate by the first to find the
constant of proportionality k Substitute the value of
k into the equation y = kx Then choose a value for x
and solve for y to find the ordered pair
20 Car 3 is not traveling at a constant speed
because 65 ___ 1 ne 85 ___
2
21 Since Car 4 is traveling at twice the speed it will
travel twice the distance as Car 2 in the same
amount of time Therefore the values in Car 4rsquos
distance column will be twice that shown in Car 2rsquos
distance column
MODULE 4
Ready to Go On
1 $140
_____ 18 ft 2
= $778 per square foot
2 $299
_____ 14 lb
asymp $021 per pound
3 $56 ______
25 gal = $224 per gallon
$3205
______ 15 gal
asymp $214 per gallon this is the better deal
4 $160
_____ 5 g
= $3200 per gram this is the better deal
$315
_____ 9 g
asymp $3500 per gram
5 No The ratio of dollars earned to lawns mowed is
not constant 15 ___ 1 ne 48 ___
3
Copyright copy by Houghton Mifflin Harcourt 26 All rights reserved
6 k = $9
___ 8euro
= $27 ____
24euro = 9 __
8 $ __
euro or 1125
$ __
euro So y = 9 __
8 x or
y = 1125x where x equals the number of euros
and y equals their value in dollars
7 The graph passes through the point ( 2 5 )
so k = 5 __ 2 servings
_______ pt
or k = 25 servings
_______ pt
Therefore
y = 5 __ 2
x or y = 25x where x equals the number
of pints and y equals the number of servings
8 The new graph will pass through the points ( 0 0 ) and ( 3 2 )
2
2
4
6
8
10
4 6 8 10Pints
Serv
ings
Frozen Yogurt
O
Therefore y = 2 __ 3 x where x equals the number of
pints and y equals the number of servings
9 Sample answer Compare corresponding values of
the variables to determine whether there is a
constant rate
Copyright copy by Houghton Mifflin Harcourt 27 All rights reserved
MODULE 5 Proportions and Percent
Are You Ready
1 22 = 22 ____ 100
= 022
2 75 = 75 ____ 100
= 075
3 6 = 6 ____ 100
= 006
4 189 = 100 + 89
= 100 ____ 100
+ 89 ____ 100
= 1 + 089
= 189
5 059 = 59
6 098 = 98
7 002 = 2
8 133 = 133
9 64
_ timesthinsp05
320
32
10 30
_ timesthinsp007
210
21
11 160
_ timesthinsp015
800
_ +1600
2400
24
12 62
_ timesthinsp032
124
_ +thinsp1860
1984
1984
13 4
_ timesthinsp12
8
_ +thinsp40
48
48
14 1000
_ timesthinsp006
6000
60
LESSON 51
Your Turn
2 x = ( $64 - 52 )
__________ $52
x = $12
____ $52
asymp 23
4 x = ( 18 - 12 )
________ 18
x = 6 ___ 18
asymp 33
5 x = ( 16 - 10 )
________ 16
x = 6 ___ 16
= 375
8 010 times $499 = $4990
$499 + $4990 = $54890
9 030 times $499 = $14970
$499 - $14970 = $34930
Guided Practice
1 x = ( $8 - $5 )
_________ $5
x = $3
___ $5
= 60
2 x = ( 30 - 20 )
_________ 20
x = 10 ___ 20
= 50
3 x = ( 150 - 86 )
__________ 86
x = 64 ___ 86
asymp 74
4 x = ( $389 - $349 )
______________ $349
x = $040
_____ $349
asymp 11
5 x = ( 14 - 13 )
________ 13
x = 1 ___ 13
asymp 8
6 x = ( 16 - 5 )
________ 5
x = 11 ___ 5 = 220
7 x = ( 64 - 36 )
_________ 36
x = 28 ___ 36
asymp 78
8 x = ( 80 - 64 )
_________ 80
x = 16 ___ 80
= 20
9 x = ( 95 - 68 )
_________ 95
x = 27 ___ 95
asymp 28
Copyright copy by Houghton Mifflin Harcourt 28 All rights reserved
10 x=( 90-45)_________
90
x=45___90
=50
11 x=( 145-132)__________
145
x=13____145
asymp9
12 x=( 64-21)_________
64
x=43___64
asymp67
13 x=( 16-0)________
16
x=16___16
=100
14 x=( 3-1__
2)_______
3
x=21__
2___
3 asymp83
15 010times$900=$090 $900+$090=$990
16 025times48=12 48-12=36cookies
17 020times340=68 $340-68=272pages
18 050times28=14 28+14=42members
19 004times$29000=$1160 $29000-$1160=$27840
20 130times810=1053 810+1053=1863songs
21 030times20=6 20+6=26miles
22 Dividetheamountofchangeinthequantitybytheoriginalamountthenexpresstheanswerasapercent
Independent Practice23
ItemOriginal
PriceNew Price
Percent Change
Increase or
DecreaseBike $110 $96 asympthinsp13 Decrease
Scooter $45 $56 asympthinsp24 Increase
TennisRacket $79 $8295 5 Increase
Skis $580 $435 25 Decrease
24 a 55
x=( 8-3)_______
8 =5__
8=625
x=( 12-7)________
12 =5___
12asymp417
Theamountofchangeisthesamebutthepercentofchangeislessfrom2010to2011
b Changewasgreatestbetween2009and2010
x=( 12-3)________
3
x=9__3=300increase
25 a Amountofchange=( 5-4)=1
Percentdecrease=1__5=20
b $100_____5 =$020each$100_____
4 =$025each
Amountofchange=$025-$020=$005
Percentincrease=$005_____$020
=25
26 Percenterror=( 136-133)___________
136 times100
=03____136
times100asymp2
Focus on Higher Order Thinking
27 a Theyhavethesame$100+$10=$110and$100+10( $100)=$110
b SylviahasmoreLeroihas$110+$10=$120andSylviahas$110+10( $110)=$121
c BecauseSylviawillhavemoreafterthesecondadditionaldepositandshewillbedepositingincreasingamountsshewillalwayshavemoreinheraccount
28 Thefinalamountisalways0becausea100decreaseofanyamountwouldbe0
29 NoOnlythefirstwithdrawalis$10Eachwithdrawalafterthatislessthan$10becauseitis10oftheremainingbalanceTherewillbemoneyleftafter10withdrawals
LESSON 52
Your Turn
2 a 1c+01c11c
b s=11times$28=$3080
3 a 200
b 1c+2c3c
5 a
1b - 024b
1b024b
b 1b-024b=076b
6 a 1p-005p095p
b 095p=$1425
CopyrightcopybyHoughtonMifflinHarcourt 29 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U2M05indd 29 103113 214 AM
Guided Practice
1 a 035s
b 1s + 035s 135s
c 135 times $3200 = $4320
d 035 times $3200 = $1120
Item Price Markup MarkupRetail
Price
2 Hat $18 15 $270 $2070
3 Book $2250 42 $945 $3195
4 Shirt $3375 75 $2531 $5906
5 Shoes $7499 33 $2475 $9974
6 Clock $4860 100 $4860 $9720
7 Painting $18500 125 $23125 $41625
8 $4500 - 022 ( $4500 ) = $3510
9 $8900 - 033 ( $8900 ) = $5963
10 $2399 - 044 ( $2399 ) = $1343
11 $27999 - 075 ( $27999 ) = $7000
12 Write the percent of markdown as a decimal
subtract the product of this decimal and the regular
price from the regular price
Independent Practice
13 a 046b
b 1b - 046b 054b
c 054 times $2900 = $1566
d 046 times $2900 = $1334
14 Regular Price $329
Sale Price $201
Regular Price $419
Sale Price $245
Regular Price $279
Sale Price $115
Regular Price $309
Sale Price $272
Regular Price $377
Sale Price $224
15 a Sample answer original price $100 final price
$050
b Sample answer original price $100 final price
$9950
c Sample answer original price $100 final price
$350
16 p = 127 ( $7400 ) = $9398
s = 127 ( $4800 ) = $6096
j = 127 ( $32500 ) = $41275
2 ( 9398 ) + 3 ( $6096 ) + $41275 = $78359
17 Either buy 3 get one free or 1 __ 4 off Either case would
result in a discount of 25 which is better than 20
Focus on Higher Order Thinking
18 No she is taking a loss Her cost for the tea is t so
the retail price is 12t The discounted price is
08 ( 12t ) or 096t which is less than t
19 No first change 201 decrease second change
251 increase The second percent change is
greater
20 Rafael can purchase the coat after 11 or 12 weeks
after 11 weeks the price is $10932 after 12 weeks
the price is $10385 and after that Danielle donates
the coat
LESSON 53
Your Turn
1 005 times $2000 = $100 $100 + $2000 = $2100
3 005 times $40000 = $2000
$2000 times 4 years = $8000
$40000 + $8000 = $48000
4 Commission $4500 times 00375 = $16875
Total $2200 + $16875 = $236875
Guided Practice
1 005 times $3000 = $150
2 015 times $7000 = $1050
3 0004 times $10000 = $040
4 15 times $2200 = $3300
5 001 times $8000 = $080
6 20 times $500 = $1000
7 a 007 times $4399 = $308
b $4399 + $308 = $4707
8 115 times $7550 = $8683
9 007 times $2000 = $140
$140 times 5 years = $700
10 003 times $550 = $1650
$1650 times 10 years = $165
$550 + $165 = $715
11 a 090 times $20 = $18
b 1085 times $18 = $1953
12 020 times $2999 = $600 tip
00625 times $2999 = $187 tax
$2999 + $600 + $187 = $3786 total
13 Write the tax rate as a decimal Then multiply the
decimal by the price of the item and add the result
to the price
Independent Practice
14 $3275 + $3988 = $7263 total meal cost
014 times $7263 = $1017 tip
$7263 + $1017 = $8280 total with tip
15 $7865 times 015 = $1180 meal discount
$7865 times 020 = $1573 tip
$7865 + $1573 - $1180 = $8258 total
16 $125 times 235 = $29375 retail ring cost
0075 times $29375 = $2203 tax
$29375 + $2203 = $31578 total with tax
Copyright copy by Houghton Mifflin Harcourt 30 All rights reserved
17 $7999 times 012 = $960 discount
$7999 - $960 = $7039 price before tax
$7039 times 10675 = $7514 total with tax
18 4 times $999 times 020 = $799 discount
4 times $999 - $799 = $3197 price before tax
$3197 times 10675 = $3413 total with tax
19 $4500 + 00725 = $32625 commission
$750 + $32625 = $107625 total income
20 $700 times 0055 = $3850 commission
$475 + $3850 = $51350 total income
21 a Multiply Sandrarsquos height by 010 and add the
product to 4 to get Pablorsquos height Then multiply
Pablorsquos height by 008 and add the product to
Pablorsquos height to get Michaelarsquos height
b Using 48 inches for 4 feet
48 inches times 01 = 48 inches so Pablorsquos height is
53 inches or 4 feet 5 inches to the nearest inch
53 inches times 008 = 42 inches so Michaelarsquos
height is 57 inches or 4 feet 9 inches to the
nearest inch
22 a $4998 times 05 = $2499 50 discount
$2499 - $1000 = $1499 $10 discount
b $4998 - $1000 = $3998 $10 discount
$3998 times 05 = $1999 50 discount
23 a $95 times 09 = $8550 discounted camera
$8550 + $1599 = $10149 total
b $1599 times 09 = $1439 discounted battery
$95 + $1439 = $10939 total
c Eric should apply the discount to the digital
camera he can save $8
d $10149 times 008 = $812 tax
$10149 + $812 = $10961 total
24 a Store 1 $22 divide 2 = $11
Store 2 $1299 times 09 = $1169
Store 1 charges $11 per shirt and Store 2
charges $1169 Therefore I would save
$069 per shirt at Store 1
b Store 3 $2098 times 045 = $944
Yes It is selling shirts at $944
Focus on Higher Order Thinking
25 Marcus should choose the option that pays $2400
plus 3 of sales He would make $2550 to $2700
per month The other option would pay only $1775
to $2050 per month
26 Percent error = ǀ 132 - 137 ǀ
____________ 137
times 100 = 05 ____ 137
asymp 36
MODULE 5
Ready to Go On
1 x = ( 63 - 36 )
_________ 36
x = 27 ___ 36
= 75 increase
2 x = ( 50 - 35 )
_________ 50
x = 15 ___ 50
= 30 decrease
3 x = ( 72 - 40 )
_________ 40
x = 32 ___ 40
= 80 increase
4 x = ( 92 - 69 )
_________ 92
x = 23 ___ 92
= 25 decrease
5 $60 times 015 = $9
$60 + $9 = $69
6 $32 times 0125 = $4
$32 + $4 = $36
7 $50 times 022 = $11
$50 - $11 = $39
8 $125 times 030 = $3750
$12500 - $3750 = $8750
9 $4800 times 0065 = $312 commission
$325 + $312 = $637 total income
10 $5310
______ $1735
asymp 31
11 Find the amount per hour that Priya makes if she
makes 20 more than James
$700 times 020 = $140
$700 + $140 = $840
Next find the amount Slobhan makes if he makes
5 less than Priya
$840 times 005 = $042
$840 - $042 = $798
Slobhan makes $798 per hour
12 Both the 6 tax and the 20 tip are applied to the
initial cost of the meal so the two percents can be
added together and multiplied by the cost
$45 times 026 = $1170
$45 + $1170 = $5670
The total cost of the meal is $5670
13 Sample answer sales tax increase discount
decrease tip increase
Copyright copy by Houghton Mifflin Harcourt 31 All rights reserved
MODULE 6 Expressions and Equations
Are You Ready
1 5 + x
2 11 - n
3 -9 ___ y
4 2x - 13
5 2x + 3
= 2 ( 3 ) + 3
= 6 + 3
= 9
6 -4x + 7
= -4 ( 1 ) + 7
= -4 + 7
= 11
7 15x - 25
= 15 ( 3 ) - 25
= 45 - 25
= 2
8 04x + 61
= 04 ( -5 ) + 61
= -20 + 61
= 41
9 2 __ 3 x - 12
= 2 __ 3
( 18 ) - 12
= 2 __ 3
times ( 18 ___ 1 ) - 12
= 36 ___ 3 - 12
= 0
10 - 5 __ 8
x + 10
= - 5 __ 8 ( -8 ) + 10
= - 5 __ 8 times- 8 __
1 + 10
= - 5 ___ 1 8
times- 8 1 __
1 + 10
= - 5 __ 1 times- 1 __
1 + 10
= 5 + 10
= 15
11 1 __ 2 divide 1 __
4
= 1 times 4 _____ 2 times 1
= 1 times 4 2 ______
1 2 times 1
= 1 times 2 _____ 1 times 1
= 2
12 3 __ 8 divide 13 ___
16
= 3 __ 8 times 16 ___
13
= 3 times 16 2 _______
1 8 times 13
= 3 times 2 ______ 1 times 13
= 6 ___ 13
13 2 __ 5 divide 14 ___
15
= 2 __ 5 times 15 ___
14
= 1 2 times 15
3 ________
1 5 times 14 7
= 1 times 3 _____ 1 times 7
= 3 __ 7
14 4 __ 9 divide 16 ___
27
= 4 __ 9 times 27 ___
16
= 1 4 times 27
3 ________
1 9 times 16 4
= 1 times 3 _____ 1 times 4
= 3 __ 4
LESSON 61
Your Turn
2 ( 3x + 1 __ 2 ) + ( 7x - 4 1 __
2 )
= 3x + 7x + 1 __ 2 - 4 1 __
2
= 10x - 4
3 ( -025x - 3 ) - ( 15x + 14 ) = -025x - 3 - 15x - 14
= -175x - 44
4 02(3b - 15c) + 6c
= 06b - 3c + 6c
= 06b + 3c
5 2 __ 3 (6e + 9f - 21g) - 7f
= 4e + 6f - 14g - 7f
= 4e - f - 14g
6 5x - 3(x - 2) - x
= 5x - 3x + 6 - x
= x + 6
7 83 + 34y - 05(12y - 7)
= 83 + 34y - 6y + 35
= 118 - 26y
Solutions KeyExpressions Equations and Inequalities
UNIT
3
Copyright copy by Houghton Mifflin Harcourt 32 All rights reserved
Guided Practice
1 baseballs 14 + (12)n tennis balls 23 + (16)n
14 + 12n + 23 + 16n
14 + 23 + 12n + 16n
37 + 28n
So the total number of baseballs and tennis balls is
37 + 28n
2 37 + 28n
37 + 28 ( 9 )
= 37 + 252
= 289
3 14 + 5(x + 3) - 7x = 14 + 5x + 15 - 7x
= 29 - 2x
4 3 ( t - 4 ) - 8 ( 2 - 3t ) = 3t - 12 - 16 + 24t
= 27t - 28
5 63c - 2 ( 15c + 41 ) = 63c - 3c - 82
= 33c - 82
6 9 + 1 __ 2 ( 7n - 26 ) - 8n = 9 + 35n - 13 - 8n
= -4 - 4 1 __ 2 n
7 2x + 12
2 ( x + 6 )
8 12x + 24
12 ( x + 2 )
9 7x + 35
7 ( x + 5 )
10 You multiply numbers or expressions to produce a
product You factor a product into the numbers or
expressions that were multiplied to produce it
Independent Practice
11 Let d = number of days
Fee for 15 food booths 15 ( 100 + 5d ) Fee for 20 game booths fee 20 ( 50 + 7d ) Amount the company is paid for the booths
15 ( 100 + 5d ) + 20 ( 50 + 7d ) = 15 ( 100 ) + 15 ( 5d ) + 20 ( 50 ) + 20 ( 7d )
= 1500 + 75d + 1000 + 140d
= 1500 + 1000 + 75d + 140d
= 2500 + 215d
12 New length 96 + l
New width 60 + w
Perimeter of new pattern
2(96 + l) + 2(60 + w)
=2(96) + 2l + 2(60) + 2w
192 + 2l + 120 + 2w
192 + 120 + 2l + 2w
312 + 2l + 2w
13 Width 3
Length 1 x-tile and 2 +1-tiles
Factors 3 and x + 2
Product 3 ( x + 2 ) = 3x + 6
14 Width 4
Length 2 x-tiles and 1 -1-tile
Factors 4 and 2x - 1
Product 4 ( 2x - 1 ) = 8x - 4
15 The area is the product of the length and width
( 6 times 9 ) It is also the sum of the areas of the
rectangles separated by the dashed line ( 6 times 5
and 6 times 4 ) So 6 ( 9 ) = 6 ( 5 ) + 6 ( 4 )
16 Perimeter of triangle ( x + 3 ) + ( 2x + 4 ) +
6x = ( x + 3 ) + ( 2x + 4 ) +
6x = 3x + 7 +
-3x = _ -3x
3x = 7 +
_ -7 = _ -7
3x - 7 =
The length of the side is 3x - 7
17 Perimeter of rectangle 2 ( 3x - 3 ) + 2 ( )
10x + 6 = 2 ( 3x - 3 ) + 2 ( )
10x + 6 = 6x - 6 + 2
_ -6x = _ -6x
4x + 6 = - 6 + 2
_ + 6 = _ + 6
4x + 12 = 2
( 4x + 12 ) divide 2 = ( 2 ) divide 2
2x + 6 =
The length of the side is 2x + 6
18 a P = 2l + 2w
Perimeter of tennis court T
2(2x + 6) + 2(x)
= 4x + 12 + 2x
= 6x + 12
Perimeter of basketball court B
2(3x - 14) + 2( 1 __ 2 x + 32)
= 6x - 28 + x + 64
= 7x + 36
b (7x + 36) - (6x + 12)
= 7x + 36 - 6x - 12
= x + 24
c Find the length of tennis court
Let x = 36
2x + 6 = 2 ( 36 ) + 6
= 72 + 6
= 78
Find the width of the basketball court
Let x = 36
1 __ 2 x + 32 = 1 __
2 ( 36 ) + 32
= 18 + 32
= 50
Find the length of the basketball court
Let x = 36
3x - 14 = 3 ( 36 ) - 14
= 108 - 14
= 94
The tennis court is 36 ft by 78 ft The basketball
court is 50 ft by 94 ft
Focus on Higher Order Thinking
19 Find the area of each small square and rectangle
( x ) ( x ) = x 2
( x ) 1 = x
( 1 ) 1 = 1
Copyright copy by Houghton Mifflin Harcourt 33 All rights reserved
x
x
1
11
1 1
x2 x x x
x 1 1 1x 1 1 1
Area =
x 2 + x + x + x + x + x + 1 + 1 + 1 + 1 + 1 + 1
= x 2 + 5x + 6
( x + 3 ) ( x + 2 ) = x 2 + 5x + 6
20 Agree To find 58 times 23 let 23 = 3 + 20 Then find
the product 58 ( 3 + 20 ) First step 58 ( 3 ) = 174
Second step 58 ( 20 ) = 1160 Third step 174 +
1160 = 1334 So 58 ( 23 ) = 58 ( 3 ) + 58 ( 20 )
21 ( 1 ) Think of 997 as 1000 - 3 So 8 times 997 = 8 ( 1000 - 3 ) By the Distributive Property
8 ( 1000 - 3 ) = 8000 - 24 = 7976
( 2 ) Think of 997 as 900 + 90 + 7 By the Distributive
Property 8 ( 900 + 90 + 7 ) = 7200 + 720 + 56 =
7976
LESSON 62
Your Turn
1 49 + z = -9
_ -49 _ -49
z = -139
2 r - 171 = -48
_ +171 _ +171
r = 123
3 -3c = 36
-3c ____ -3
= 36 ___ -3
c = -12
5 x - 15 = 525
_ +15 _ +15
x = 675
The initial elevation of the plane is 675 miles
6 x ___ 35
= -12
x ___ 35
( 35 ) = -12 ( 35 )
x = -42
The decrease in the value of the stock was $420
7 25x = 75
25x ____ 25
= 75 ___ 25
x = 3
The power was restored in 3 hours
Guided Practice
1 Let x represent the number of degrees warmer the
average temperature is in Nov than in Jan
x + ( -134 ) = -17 or x - 134 = -17
x - 134 = -17
_ +134 _ +134
x = 117
The average temperature in November is 117degF
warmer
2 Let x represent the number of days it takes the
average temperature to decrease by 9degF
-1 1 __ 2 x = -9
( - 2 __ 3 ) ( - 3 __
2 x ) = ( - 2 __
3 ) ( -9 )
x = 18 ___ 3
x = 6
It took 6 days for the temperature to decrease by 9degF
3 -2x = 34
-2x ____ -2
= 34 ___ -2
x = -17
4 y - 35 = -21
_ + 35 _ + 35
y = 14
y = 14
5 2 __ 3 z = -6
( 3 __ 2 ) 2z ___
3 = ( 3 __
2 ) ( -6 )
z = -9
6 Sample answer It helps me describe the problem
precisely and solve it using inverse operations
Independent Practice
7 Let x equal the elevation of Mt Everest
x - 870737 = 203215
_ +870737 _ +870 737
x = 2902887
The elevation of Mt Everest is 2902887 ft
8 Let x equal the number of feet Liam descended
2825131 - x = 2320106
_ -2825131 _ -2825131
-x = - 505025
x = 505025
Liam descended 505025 ft
His change in elevation was -505025 ft
9 Let x equal the elevation of Mt Kenya
2825131 - x = 1119421
_ -2825131 _ -2825131
-x = -1705710
x = 1705710
The elevation of Mt Kenya is 170571 ft
10 Find the change in elevation
1250 - 935 = 315
Use an equation
Let x = the number of minutes the balloon
descends
( -22 1 __ 2 ) x = -315
( - 45 ___ 2 ) x = -315
( - 2 ___ 45
) ( - 45 ___ 2 ) x = -315 ( - 2 ___
45 )
x = 14
It will take the balloon 14 minutes to descend
11 Find the change in elevation
4106 - 3205 = 901
Use an equation to find the rate of descent
Copyright copy by Houghton Mifflin Harcourt 34 All rights reserved
Let x = rate of descent
34x = 901
34x ____ 34
= 901 ____ 34
x = 265 = 26 1 __ 2
The rate of descent was 26 1 __ 2 feet per minute
12 Let x = the number of degrees warmer Montanarsquos
average temperature is than Minnesotarsquos
- 25 + x = -07
_ + 25 _ + 25
x = 18
Montanarsquos average 3-month temperature is 18degC
warmer than Minnesotarsquos
13 Let x = the number of degrees warmer Floridarsquos
average temperature is than Montanarsquos
181 - x = -07
_ - 181 _ -181
-x = -188
x = 188
Floridarsquos average 3-month temperature is 188degC
warmer than Montanarsquos
14 Let x = the number of degrees the average
temperature in Texas would have to change
125 + x = 181
_ -125 _ -125
x = 56
It would have to increase by 56degC
15 Let x = the number of yards the team must get on
their next play
-26 1 __ 3
+ x = 10
+26 1 __ 3
______
+26 1 __ 3
______
x = 36 1 __ 3
The team needs to get 36 1 __ 3 yards on their next play
16 Let x = the number of seconds
( -2 1 __ 2 ) x = -156
( -25 ) x = -156
( -25 _____ -25
) x = -156 ______ -25
x = 624
It takes the diver 624 seconds to reach -156 feet
17 Sample answer The elevation is the product of the
rate and the time
18 Let x = the total amount withdrawn
x __ 5 = 455
( 5 ) x __ 5 = 455 ( 5 )
x = 2275
The total amount she withdrew was $22750
Sample answer
$4550 asymp $50 and $50 times 5 = $250 which is close
to $22750
Focus on Higher Order Thinking
19 ( 1 ) The elevations of the diver and the reef both are
below sea level
( 2 ) The change in the planersquos elevation the plane
descends the plane is moving from a higher to a
lower elevation
20 -4x = -48
( -4x ____ -4
) = -48 _____ -4
x = 12
- 1 __ 4 x = -48
( -4 ) ( - 1 __ 4 ) x = -48 ( -4 )
x = 192
192 ____ 12
= 16
In the first case -4x = -48 you divide both sides
by -4 In the second - 1 __ 4 x = -48 you multiply
both sides by -4 The second solution (192) is
16 times the first (12)
21 Add the deposits and the withdrawals Let x repre-
sent the amount of the initial deposit Write and
solve the equation x + deposits - withdrawals =
$21085
LESSON 63
Your Turn
4 Let x represent the number of video games Billy
purchased
Original balance on gift card $150
Cost for x video games $35 middot x
Final balance on gift card $45
Original balance minus $35 times number of games equals $45
darr darr darr darr darr darr darr $150 - $35 middot x = $45
Equation 150 - 35x = 45
5 Sample answer You order x pounds of coffee from
Guatemala at $10 per pound and it costs $40 to
ship the order How many pounds can you order so
that the total cost is $100
Guided Practice
1
+ + ++ ++
+++ + +
+++
2
----
+ ++ ++
- - -
Copyright copy by Houghton Mifflin Harcourt 35 All rights reserved
3 Let a represent the number of adults that attend
Ticket cost for 1 child = $6
Ticket cost for a adults = $9 middot a
Total cost for movie = $78
cost for child plus $9 times number of adults equals $78
darr darr darr darr darr darr darr $6 + $9 middot a = $78
Equation 6 + 9a = 78
4 x is the solution of the problem
2x is the quantity you are looking for multiplied by 2
+ 10 means 10 is added to 2x
= 16 means the result is 16
5 Sample answer A department store is having a sale
on recliners buy two and get a discount of $125
Sanjay purchases two recliners and the total cost
(before taxes) is $400 What is the price of a single
recliner not including any discounts
6 Choose a variable to represent what you want to
find Decide how the items of information in the
problem relate to the variable and to each other
Then write an equation tying this all together
Independent Practice
7 On one side of a line place three negative variable
tiles and seven +1-tiles and then on the other side
place 28 +1-tiles
8 Let d represent the number of days Val rented the
bicycle
Flat rental fee $5500
Cost for d days of rental $850 middot dTotal cost $123
$850 times number of days plus flat fee equals total cost
darr darr darr darr darr darr darr $850 bull d + $55 = $123
Equation 85d + 55 = 123
9 Let r represent the number of refills
Refill mug cost $675
Cost for r refills $125 middot r Total cost $3175
$125 times number of refills plus refill mug cost equals total cost
darr darr darr darr darr darr darr $125 bull r + $675 = $3175
Equation 125r + 675 = 3175
10 Let n represent the number of weekday classes
The Saturday class lasts 60 minutes
The length of time for the weekday classes is 45 middot n
The total number of minutes for all classes in a week
is 28545 minutes times number of plus minutes for equals total minutes
weekday classes Saturday class
darr darr darr darr darr darr darr45 bull n + 60 = 285
Equation 45n + 60 = 285
11 Let n represent the number of African animals
Half the number of African animals is 1 __ 2 n
45 more than the number of African animals
means + 45
The total number of animals is 172
half times number of and 45 more than number equals total number
African animals of African animals of animals
darr darr darr darr darr darr
1 _ 2
bull n + 45 = 172
Equation 1 __ 2 n + 45 = 172
12 Let u represent the number of uniforms
Cost for basketball equipment $548
Cost for u uniforms $2950 middot uTotal cost $2023
$2950 times number of plus cost for basketball equals total cost
uniforms equipment
darr darr darr darr darr darr darr $2950 bull u + $548 = $2023
Equation 295u + 548 = 2023
13 Let x represent the number of weeks
Initial amount in account $500
$20 per week 20 middot xFinal amount in account $220
initial amount minus 20 times number of equals final amount
weeks
darr darr darr darr darr darr darr 500 - 20 bull x = 220
Equation 500 - 20x = 220
14 a The equation adds 25 but Deenarsquos scenario
involves subtracting 25
b Let x represent the number of shirts
Cost of shirts before discount 9 middot xDiscount means subtract
Amount of discount $25
Total bill $88
9 times number of minus discount equals total
shirts bill
darr darr darr darr darr darr darr 9 bull x - 25 = 88
Equation 9x - 25 = 88
c Sample answer I bought some shirts at the store
for $9 each and a pair of jeans for $25 making
my bill a total of $88 How many shirts did I buy
15 a Let c represent the number of children
Flat fee for Sandy $10
Cost per child for Sandy $5 middot cTotal charge for Sandy $10 + $5c
Total charge for Kimmi $25
To compare the two costs set these values equal
Equation 10 + 5c = 25
b Solve the equation to find c the number of
children a family must have for Sandy and Kimmi
to charge the same amount
10 + 5c = 25
10 - 10 + 5c = 25 - 10
5c = 15
5c ___ 5 = 15 ___
5
c = 3
3 children
c They should choose Kimmi because she charges
only $25 If they chose Sandy they would pay
10 + 5 ( 5 ) = $35
Copyright copy by Houghton Mifflin Harcourt 36 All rights reserved
Focus on Higher Order Thinking
16 To get Andresrsquo equation you can multiply every
number in Peterrsquos equation by 4 To get Peterrsquos
equation you can divide every number in Andrewrsquos
equation by 4 or multiply by 1 __ 4
17 Part of the equation is written in cents and part in
dollars All of the numbers in the equation should be
written either in cents or dollars
18 Sample answer Cici has a gift card with a balance
of 60 She buys several T-shirts for $8 each Her new
balance is $28 after the purchases Write an
equation to help find out how many T-shirts Cici
bought
LESSON 64
Your Turn
1 Model the equation
+ ++ +
+ ++ ++ +
+ ++ ++ +
++
Remove 5 +1-tiles from each side of the mat
+ ++ +
+ ++ ++ +
+ ++ ++ +
++
Divide each side into two equal groups
++
+ ++ +
++
The solution is x = 3
++ ++
2 Model the equation
+ + ++ + ++ +
+++
+++
__
Add 1 +1-tile to each side of the mat Note that
a negative-positive tile pair results in zero
+ + ++ + ++
++ +
+++
+++
__
Divide each side into two equal groups
+ + ++++ + +++
The solution is n = 3
+ + +++
3 Model the equation
++++
______
______
____
Add 3 +1-tiles to each side of the mat Note that
a negative-positive tile pair results in zero
++++
+
++
+
++
______
______
____
Divide each side into two equal groups
++++
____
The solution is a = -1
++ __
Copyright copy by Houghton Mifflin Harcourt 37 All rights reserved
4 Model the equation
____
________
++
Add 2 -1-tiles to each side of the mat Note that
a negative-positive tile pair results in zero
________
________
++
____
Divide each side into two equal groups
________
________
We get -y = -1
____
In order to change -y to y add a positive y-variable
tile to each side
++
__ ++ __
Add 1 +1-tile to each side of the mat
++++
__
The solution is y = 1
+++
6 3n + 10 = 37
Solve the equation for n
3n + 10 = 37
-10 ____
-10 ____
3n = 27
3n ___ 3 = 27 ___
3
n = 9
The triplets are 9 years old
7 n __ 4 - 5 = 15
Solve the equation for n
n __ 4 - 5 = 15
+5 ___
+5 ___
n __ 4 = 20
n __ 4 ( 4 ) = 20 ( 4 )
n = 80
The number is 80
8 -20 = 5 __ 9 ( x - 32 )
Solve the equation for x
-20 = 5 __ 9 ( x - 32 )
-20 = 5 __ 9 x - 160 ____
9
+ 160 ____ 9
______
+ 160 ____ 9
______
- 20 ___ 9 = 5 __
9 x
- 20 ___ 9 divide ( 5 __
9 ) = 5 __
9 x divide ( 5 __
9 )
4 20 times 9
1 _______
9 1 times 5
1 = x
- 4 __ 1 = x
-4 = x
The temperature in the freezer is -4degF
9 120 - 4x = 92
Solve the equation for x
120 - 4x = 92
-120 _____
-120 _____
- 4x = -28
-4x ____ -4
= -28 ____ -4
x = 7
She had 7 incorrect answers
Copyright copy by Houghton Mifflin Harcourt 38 All rights reserved
Guided Practice
1 To solve the equation with algebra tiles first remove
one +1-tile from both sides Then divide each side
into two equal groups
2 Remove 1 +1-tile from each side
++++
+ +++++++++
Divide each side into two equal groups
++++
++++++++
The solution is x = 4
++ + + + +
3 Let w = the width of the frame
2 times height plus 2 times width equals perimeter
darr darr darr darr darr darr darr darr darr2 bull 18 + 2 bull w = 58
Solve the equation
2 ( 18 ) + 2w = 58
36 + 2w = 58
36 - 36 + 2w = 58 - 36
2w = 22
2w ___ 2 = 22 ___
2
w = 11
The width is 11 inches
4 1200 minus 25x = 500
Solve the equation for x
1200 - 25x = 500
_ -1200 _ -1200
-25x = -700
-25x _____ -25
= -700 _____ -25
x = 28
The manager will reorder in 28 days
5 Use the inverse operations of the operations
indicated in the problem If the equation does
not involve parentheses use addition or subtraction
before multiplication or division to solve the
equation
Independent Practice
6 9s + 3 = 57
9s + 3 - 3 = 57 - 3
9s = 54
9s ___ 9 = 54 ___
9
s = 6
7 4d + 6 = 42
4d + 6 - 6 = 42 - 6
4d = 36
4d ___ 4 = 36 ___
4
d = 9
8 115 - 3y = -485
115 - 115 - 3y = -485 - 115
thinsp-3y = -60
-3y
____ -3
= -60 ____ -3
y = 20
9 k __ 2 + 9 = 30
k __ 2 + 9 - 9 = 30 - 9
k __ 2 = 21
2 sdot k __ 2 = 2 sdot 21
k = 42
10 g
__ 3 - 7 = 15
g
__ 3 - 7 + 7 = 15 + 7
g
__ 3 = 22
3 sdot g
__ 3 = 3 sdot 22
g = 66
11 z __ 5 + 3 = -35
z __ 5 + 3 - 3 = -35 - 3
z __ 5 = -38
5 sdot z __ 5 = 5 ( -38 )
z = -190
12 -9h - 15 = 93
-9h - 15 + 15 = 93 + 15
-9h = 108
-9h ____ -9 = 108 ____
-9
h = -12
13 - 1 __ 3 (n + 15) = -2
- 1 __ 3 n - 5 = -2
- 1 __ 3 n - 5 + 5 = -2 + 5
- 1 __ 3 n = 3
-3 sdot - 1 __ 3 n = -3 sdot 3
n = -9
14 -17 + b __ 8 = 13
-17 + 17 + b __ 8 = 13 + 17
b __ 8 = 30
8 sdot b __ 8 = 8 sdot 30
b = 240
Copyright copy by Houghton Mifflin Harcourt 39 All rights reserved
15 7 ( c - 12 ) = -21
7c - 84 = -21
_ +84 _ +84
7c = 63
7c ___ 7 = 63 ___
7
c = 9
16 -35 + p
__ 7 = -52
-35 + 35 + p
__ 7 = -52 + 35
p
__ 7 = -17
7 sdot p
__ 7 = -17 sdot 7
p = -119
17 46 = -6t - 8
46 + 8 = -6t - 8 + 8
54 = -6t
54 ___ -6
= -6t ____ -6
t = -9
18 Let a = the original amount in the account
Double the (original plus 26) equals new
sum of amount amount
darr darr darr darr darr darr
2 (a + $26) = $264
Solve the equation
2 ( a + 26 ) = 264
2 ( a + 26 )
_________ 2 = 264 ____
2
a + 26 = 132
a + 26 - 26 = 132 - 26
a = 106
Puja originally had $106 in the account
19 Let t = the temperature 6 hours ago
Twice temperature less 6 degrees equals current
6 hours ago temperature
darr darr darr darr darr darr 2middot t - 6 = 20
Solve the equation
2t - 6 = 20
2t - 6 + 6 = 20 + 6
2t = 26
2t __ 2 = 26 ___
2
t = 13
Six hours ago it was 13 degF in Smalltown
20 -35 = 5 __ 9 ( x - 32 )
-35 = 5 __ 9 x - 160 ____
9
+ 160 ____ 9
______
+ 160 ____ 9
- 155 ____ 9 = 5 __
9 x
thinsp- 155 ____ 9 divide ( 5 __
9 ) = 5 __
9 x divide ( 5 __
9 )
-thinsp 31
155 times 9
1
= x
9 1
times 5
1
- 31 ___ 1 = x
-31 = x
The temperature is -31degF
21 Let a = Artaudrsquos ageopposite of Artaudrsquos age add 40 equals 28
darr darr darr darr darr darr(-) a + 40 = 28
Solve the equation
-a + 40 = 28
-a + 40 - 40 = 28 - 40
-a = -12
-a ___ -1
= -12 ____ -1
a = 12
Artaud is 12 years old
22 Let c = number of customers when Sven startedtwice number of
customers when Sven started
plus 11 more equals present number of customers
darr darr darr darr darr2 middot c +11 = 73
Solve the equation
2c + 11 = 73
2c + 11 - 11 = 73 - 11
2c = 62
2c ___ 2 = 62 ___
2
c = 31
Sven had 31 customers when he started
23 Let p = original price of the jacket
half original less $6 equals amount
price paid
darr darr darr darr darr
1 __ 2
middot p -6 = 88
Solve the equation
1 __ 2 p - 6 = 88
1 __ 2 p - 6 + 6 = 88 + 6
1 __ 2 p = 94
2 sdot 1 __ 2 p = 2 sdot 94
p = 188
The original price was $188
Copyright copy by Houghton Mifflin Harcourt 40 All rights reserved
24 115 minus 8n = 19
Solve the equation for n
115 - 8n = 19
_ -115 _ -115
-8n = -96
-8n _____ -8
= -96 _____ -8
n = 12
They had 19 apples left after 12 days
25 -55x + 056 = -164
-55x + 056 - 056 = -164 - 056
-55x = -22
-55x ______ -22
= -22 _____ -22
x = 04
26 -42x + 315 = -651
-42x + 315 - 315 = -651 - 315
-42x = -966
-42x ______ -42
= -966 ______ -42
x = 23
27 k ___ 52
+ 819 = 472
k ___ 52
+ 819 - 819 = 472 - 819
k ___ 52
= -347
52 sdot k ___ 52
= 52 ( -347 )
k = -18044
28 Sample answer -3x - 5 = -26
29 Sample answer x __ 5 + 10 = 5
30 When dividing both sides by 3 the student forgot to
divide 2 by 3
3x + 2 = 15
3x ___ 3 + 2 __
3 = 15 ___
3
x + 2 __ 3 = 5
- 2 __ 3
___
- 2 __ 3
___
x = 5 - 2 __ 3
x = 5 times3
___ 1
times3 - 2 __
3
x = 15 ___ 3 - 2 __
3
x = 13 ___ 3 or 4 1 __
3
The solution should be x = 4 1 __ 3
31 a 2(x + 40) = 234
Solve the equation for x
2x + 80 = 234
2x + 80 - 80 = 234 - 80
2x = 154
2x ___ 2 = 154 ____
2
x = 77
Trey saved $77
b Sample answer In both solutions you would
divide $234 by 2 then subtract 40 234 divide 2 ndash 40
= 77 These are the same operations applied in
the same order as when solving the equation
Focus on Higher Order Thinking
32 F = 18c + 32
F - 32 = 18c + 32 - 32
F - 32 = 18c
F - 32 ______ 18
= 18c ____ 18
F - 32 ______ 18
= c
33 P = 2 ( ℓ + w ) P = 2ℓ + 2w
P - 2ℓ = 2ℓ - 2ℓ + 2w
P - 2ℓ = 2w
P - 2ℓ ______ 2 = 2w ___
2
P - 2ℓ ______ 2 = w
34 ax + b = c
ax + b - b = c - b
ax = c - b
ax ___ a = c - b ______ a
x = c - b ______ a
MODULE 6
Ready to Go On
1 Add the amounts for the cost of first day of the field
trip with the second day of the field trip where n is
the number of members in the club
15n + 60 + 12n + 95
Therefore the total cost of the two-day field trip can
be written as the expression 27n + 155
2 h + 97 = -97
_ -97 _ -97
h = -194
3 - 3 __ 4 + p = 1 __
2
+ 3 __ 4 + 3 __
4
p = 1 __ 2 + 3 __
4
p = 1 times2
___ 2
times2 + 3 __
4
p = 2 __ 4 + 3 __
4
p = 5 __ 4
4 -15 = -02k
-15 _____ -02
= -02k ______ -02
75 = k
Copyright copy by Houghton Mifflin Harcourt 41 All rights reserved
5 y ___
-3 = 1 __
6
y ___
-3 ( -3 ) = 1 __
6 ( -3 )
y = 1 __ 6 times -3 ___
1
y = -3 ___ 6
y = -1 ___ 2
6 - 2 __ 3
m = -12
- 2 __
3 m _____
- 2 __ 3 = -12 ____
- 2 __ 3
m = -12 divide - 2 __ 3
m = -12 ____ 1 divide - 2 __
3
m = -12 ____ 1 times - 3 __
2
m = -36 ____ -2
m = 18
7 24 = - t ___ 45
24 ( 45 ) = - t ___ 45
( 45 )
108 = -t
-108 = t
8 Let d represent the number of the day after the first
day for example d = 1 means the first day after the
day he started number of number number
2 times day after plus of sit-ups equals of sit-ups
first day first day today
darr darr darr darr darr darr darr
2 middot d + 15 = 33
Equation 2d + 15 = 33
9 5n + 8 = 43
5n + 8 - 8 = 43 - 8
5n = 35
5n ___ 5 = 35 ___
5
n = 7
10 y __
6 - 7 = 4
y __
6 - 7 + 7 = 4 + 7
y __
6 = 11
6 sdot y __
6 = 6 sdot 11
y = 66
11 8w - 15 = 57
8w - 15 + 15 = 57 + 15
8w = 72
8w ___ 8 = 72 ___
8
w = 9
12 g
__ 3 + 11 = 25
g
__ 3 + 11 - 11 = 25 - 11
g
__ 3 = 14
3 sdot g
__ 3 = 3 sdot 14
g = 42
13 f __ 5 - 22 = -25
f __ 5 - 22 + 22 = -25 + 22
f __ 5 = -03
5 sdot f __ 5 = 5 ( -03 )
f = -15
14 - 1 __ 4 (p + 16) = 2
- 1 __ 4 p - 4 = 2
- 1 __ 4 p - 4 + 4 = 2 + 4
- 1 __ 4 p = 6
-4 sdot - 1 __ 4 p = 6 sdot -4
p = -24
15 Sample answer Analyze the situation to determine
how to model it using a two-step equation Solve
the equation Interpret the solution in the given
situation
Copyright copy by Houghton Mifflin Harcourt 42 All rights reserved
MODULE 7 Inequalities
Are You Ready
1 9w = -54
9w ___ 9 = -54 ____
9
w = -6
2 b - 12 = 3
thinsp _ + 12 = _ + 12
b = 15
3 n __ 4
= -11
4 times n __ 4
= 4 ( -11 )
n = -44
4-7
ndash5ndash10 0 5 10
75 4 6
8 3 - (-5)
3 + 5
8
9 -4 - 5
-9
10 6 - 10
-4
11 -5 - (-3)
-5 + 3
-2
12 8 - (-8)
8 + 8
16
13 9 - 5
4
14 -3 - 9
-12
15 0 - (-6)
0 + 6
6
LESSON 71
Your Turn
4 y minus 5 ge minus7
_ +5 _ +5
y ge minus2
-4-5 -3 -2-1 0 1 2 3 4 5
Check Substitute 0 for y
minus1 ge -8
minus1(minus2) le -8(minus2)
2 le 16
5 21 gt 12 + x
_ -12 _ minus12
9 gt x
x lt 9
10 2 3 4 5 6 7 8 9 10
Check Substitute 8 for x
21 gt 12 + 8
21 gt 12 + 8
21 gt 20
6 -10y lt 60
-10y
_____ -10
lt 60 ____ -10
y gt -6
-10-9 -8 -7 -6 -5 -4 -3 -2-1 0 1
Check Substitute -5 for y
-10y lt 60
-10(-5) lt 60
50 lt 60
7 7 ge - t __ 6
7(-6) le - t __ 6 (-6)
-42 le t
t ge -42
-46 -45 -44 -43 -42 -41 -40-47
Check Substitute -36 for t
7 ge - t __ 6
7 ge - ( -36 ____
6 )
7 ge 6
8 Write and solve an inequality
Let m = the number of months
35m le 315
35m ____ 35
le 315 ____ 35
m le 9
Tony can pay for no more than 9 months of his gym
membership using this account
Guided Practice
1 -5 le -2
_ +7 _ +7
2 le 5
2 -6 lt -3
-6 ___ -3
gt -3 ___ -3
2 gt 1
3 7 gt -4
_ -7 _ -7
0 gtthinsp -11
Copyright copy by Houghton Mifflin Harcourt 43 All rights reserved
4 -1 ge -8
-1 ( -2 ) le -8 ( -2 )
2 le 16
5 n - 5 ge -2
_ +5 _ +5
n ge 3
-5 -4 -3 -2-1 0 3 4 51 2
Check Substitute 4 for n
n - 5 ge -2
4 - 5 ge -2
-1 ge -2
6 3 + x lt 7
_ -3 _ -3
x lt 4
-2-1 0 3 4 5 6 7 81 2
Check Substitute 3 for x
3 + x lt 7
3 + 3 lt 7
6 lt 7
7 -7y le 14
-7y
____ -7 ge 14 ___ -7
y ge -2
-5-6-7 -4 -3 -2-1 0 1 2 3
Check Substitute -1 for y
-7y le 14
-7 ( -1 ) le 14
7 le 14
8 b __ 5 gt -1
b __ 5 ( 5 ) gt -1 ( 5 )
b gt -5
-5-6-7-8 -4 -3 -2-1 0 1 2
Check Substitute 0 for b
b __ 5 gt -1
0 __ 5 gt
-1
0 gt -1
9 a -4t ge -80
b -4t ge -80
-4t ____ -4
le -80 ____ -4
t le 20
It will take the physicist 20 or fewer hours to change
the temperature of the metal
c The physicist would have to cool the metal for
more than 20 hours for the temperature of the
metal get cooler than -80deg C
10 You reverse the inequality symbol when you divide
or multiply both sides of an inequality by a negative
number
Independent Practice
11 x - 35 gt 15
_ + 35 _ +35
x gt 50
100 20 30 40 50 60 70 80 90100
Check Substitute 51 for x
x - 35 gt 15
51 minus 35 gt 15
16 gt 15
12 193 + y ge 201
_ -193 _ minus193
y ge 8
10 2 3 4 5 6 7 8 9 10
Check Substitute 9 for y
193 + y ge 201
193 + 9 ge 201
202 ge 201
13 - q
__ 7 ge -1
- q
__ 7 ( -7 ) le -1 ( -7 )
q le 7
8 9 105 6 70 1 2 3 4
Check Substitute ndash14 for q
- q
__ 7 ge -1
- -14 ____ 7 ge
-1
2 ge -1
14 -12x lt 60
-12x _____ -12
gt 60 ____ -12
x gt -5
0-10-9 -8 -7 -6 -5 -4 -3 -2-1
Check Substitute -4 for x
-12x lt 60
-12 ( -4 ) lt 60
48 lt 60
15 5 gt z -3
_ +3 _ +3
8 gt z
z lt 8
10 2 3 4 5 6 7 8 9 10
Check Substitute 7 for z
5 gt z - 3
5 gt 7 - 3
5 gt 4
Copyright copy by Houghton Mifflin Harcourt 44 All rights reserved
16 05 le y __
8
05 ( 8 ) le y __
8 ( 8 )
4 le y
y ge 4
8 9 105 6 70 1 2 3 4
Check Substitute 8 for y
05 le y __
8
05 le 8 __
8
05 le 1
17 Write and solve an inequality
Let x = the number of inches
12 + x le 28
_ -12 _ -12
x le 16
The puppy will grow at most 16 inches more
18 Write and solve an inequality
Let w = the total weight of the kittens
w __ 7 lt 35
w __ 7 ( 7 ) lt 35 ( 7 )
w lt 245
The possible combined weights of the kittens is any
weight less than 245 ounces but greater than 0
19 Write and solve an inequality
Let s = the number of sides
6s le 42
6s ___ 6 le 42 ___
6
s le 7
The length of a side is at most 7 inches
20 Write and solve an inequality
Let x = the amount Tom needs to spend
3025 + x ge 50
_ -3025 _ -3025
x ge 1975
Tom needs to spend at least $1975
21 Write and solve an inequality
Let w = the width of the region
155w ge 1705
155w ______ 155
ge 1705 _____ 155
w ge 11
The possible width of the region is at least 11 feet
22 Write and solve an inequality
Let t = the number of seconds
thinsp-12t lt -120
-12t _____ -12
gt -120 _____ -12
t gt 10
No let t be the number of seconds the descent
takes the inequality is ndash12t lt -120 so t gt 10 so
the submarinersquos descent takes 10 seconds or more
23 Write and solve an inequality
Let s = the amount of spinach
3s le 10
3s ___ 3 le 10 ___
3
s le 3 1 __ 3
The greatest amount of spinach she can buy is 3 1 __ 3
pounds
24 Write and solve an inequality
Let m = the amount of money Gary has
m ___ 05
le 55
m ___ 05
( 05 ) le 55 ( 05 )
m le 275
Gary has at most $275
25 Write and solve an inequality
Let x = the number of pounds of onions
125x le 3
125x _____ 125
le 3 ____ 125
x le 24
No 125x le 3 x le 24 so 24 pounds of onions is
the most Florence can buy 24 lt 25 so she cannot
buy 25 pounds
Focus on Higher Order Thinking
26 If you divide both sides of -7z ge 0 by -7 and do
not reverse the inequality symbol you get z ge 0
This is incorrect because if you choose a value from
the possible solutions such as z = 1 and substitute
it into the original equation you get -7 ge 0 which is
not true
27 x gt 9 for each inequality in each case the number
added to x is 9 less than the number on the right
side of each inequality so x gt 9 is the solution
28 Find the formula for the volume of a rectangular
prism
V = lwh
Write and solve an inequality
Let h = the height in inches
( 13 ) ( 1 __ 2 ) h lt 65
65h lt 65
65h ____ 65
lt 65 ___ 65
h lt 10
All heights greater than 0 in and less than 10 in
( 13 ) ( 1 __ 2 ) h lt 65 65h lt 65 h lt 10 A height cannot
be 0 or less than 0 so h gt 0 and h lt 10
Copyright copy by Houghton Mifflin Harcourt 45 All rights reserved
LESSON 72Your Turn
3 Let a represent the amount each member must
raise
Number of members 45
Starting amount $1240
Target amount $6000
starting number amount each is greater target
amount plus of members times member than or amount
must raise equal to
darr darr darr darr darr darr darr $1240 + 45 middot a ge $6000
Equation 1240 + 45a ge 6000
4 Let n represent the greatest number of rides Ella
can go on
Starting amount $40
Admission price $6
Cost for each ride $3
admission cost for number is less starting
price plus each ride times of rides than or amount
equal to
darr darr darr darr darr darr darr $6 + $3 middot n le $40
Equation 6 + 3n le 40
5 x is the solution of the problem the quantity you
are looking for
3x means that for a reason given in the problem
the quantity you are looking for is multiplied by 3
+ 10 means that for a reason given in the problem
10 is added to 3x
gt 30 means that after multiplying the solution x by
3 and adding 10 to it the result must be greater
than 30
Sample answer An exam consists of one essay
question worth 10 points and several multiple choice
questions worth 3 points each If Petra earns full
points on the essay question how many multiple
choice questions must she get right in order to get
a score greater than 30 points
6 x is the solution of the problem the quantity you are
looking for
5x means that for a reason given in the problem
the quantity you are looking for is multiplied by 5
-50 means that for a reason given in the problem
50 is subtracted from 5x
le 100 means that after multiplying the solution x by
5 and subtracting 50 from it the result must be less
than or equal to 100
Sample answer Miho has $100 to spend on her
garden She spends $50 on gardening supplies
Vegetable plants cost $5 each What is the greatest
number of plants she can buy
Guided Practice
1
- -- -
-
lt
++++++
+ + ++ + +
+
2
---
gt
+ + ++ + +
+ + ++ + +
+ + +
3 Let a represent the amount each member must
raise
Amount to be raised $7000
Amount already raised $1250
Number of members 92 amount number of amount each is greater target
already plus members times member than or amount
raised raises equal to
darr darr darr darr darr darr darr 1250 + 92 times a ge 7000
The inequality that represents this situation is
1250 + 92a ge 7000
4 x is the solution of the problem 7x is the solution
multiplied by 7 -18 means that 18 is subtracted
from 7x le 32 means that the result can be no
greater than 32
5 Sample answer Alexa has $32 to spend on T-shirts
for her friends She has a gift card worth $18 T-shirts
cost $7 each How many T-shirts can Alexa buy
6 Sample answer Choose a variable to represent
what you want to find Decide how the information in
the problem is related to the variable Then write an
inequality
Independent Practice
7 number possible amount is
of times amount each minus for more $200
friends friend earns supplies than
darr darr darr darr darr darr darr 3 middot a - $28 gt $200
3a + 28 gt 200
Let a = possible amount each friend earned
8 cost of number cost of less than amount
bagel times of bagels plus cream or equal Nick
cheese to has
darr darr darr darr darr darr darr $075 middot n + $129 le $700
075n + 129 le 700
Let n = the number of bagels Nick can buy
9 number max amount amount less than total amount
of shirts times each shirt minus of gift or equal Chet can
can cost certificate to spend
darr darr darr darr darr darr darr 4 sdot a - 25 le 75
4a - 25 le 75Let a = the maximum amount each shirt can cost
Copyright copy by Houghton Mifflin Harcourt 46 All rights reserved
10 number of number number of is less total
seats in plus of rows on times seats in than equal number
balcony ground floor one row equal to of people
darr darr darr darr darr darr darr 120 + 32 middot n le 720
120 + 32n le 720
Let n = the number of people in each row
11 amount commission amount greater than earning
earned per plus rate times of sales or equal to for this
month month
darr darr darr darr darr darr darr 2100 + 005 middot s ge 2400
2100 + 005s ge 2400
Let s = the amount of her sales
12 number number average greater
of cans plus of days times number of than goal
collected cans per day
darr darr darr darr darr darr darr 668 + 7 n gt 2000
668 + 7n gt 2000
Let n = the average number of cans collected each
day
13 cost per cost per number of less than total amount
month plus CD times CDs she or equal spent in
buys to a month
darr darr darr darr darr darr darr
$7 + $10 middot c le $100
7 + 10c le 100
Let c = the number of CDs Joanna buys
14 cost of cost for number of less than total amount
belt plus each times shirts he or equal of money
shirt can buy to Lionel has
darr darr darr darr darr darr darr
$22 + $17 middot n le $80
22 + 17n le 80
Let n = the number of shirts he can buy
15 Sample answer Mr Craig is buying pizzas for the
7th grade field day He can spend up to $130 and
needs 15 pizzas He has a $20 coupon How much
can he spend per pizza $10 or less per pizza
16 ldquoat leastrdquo in this case means m ge 25
17 ldquono greater thanrdquo in this case means k le 9
18 ldquoless thanrdquo in this case means p lt 48
19 ldquono more thanrdquo in this case means b le -5
20 ldquoat mostrdquo in this case means h le 56
21 ldquono less thanrdquo in this case means w ge 0
22 The average score of the three tests Marie has
already taken and the three she will still take
is given by
95 + 86 + 89 + 3s
________________ 6
where s is the average score on the three remaining
tests
This value needs to be greater than or equal to 90
so the inequality can be written as
95 + 86 + 89 + 3s
________________ 6 ge 90 or
95 + 86 + 89 + 3s ge 540 or
270 + 3s ge 540
Focus on Higher Order Thinking
23 5 + 10 lt 20 Sample answer If the combined length
of two sides of a triangle is less than the length of
the third side the two shorter sides will not be long
enough to form a triangle with the third side Here
the combined length of 5 ft and 10 ft is 15 ft not
enough to make a triangle
24 -m gt 0 Sample answer Since m is less than 0 it
must be a negative number -m represents the
opposite of m which must be a positive number
since the opposite of a negative number is positive
So -m gt 0
25 n gt 1 __ n if n gt 1
n lt 1 __ n if n lt 1
n = 1 __ n if n = 1
LESSON 73
Your Turn
1 Model the inequality
++
++++
+++
++++
++++
+++
gt
Add seven -1-tiles to both sides of the mat
++
++++
+++
++++
++++
+++
gt
- -- -- --
- -- -- --
Remove zero pairs from both sides of the mat
++
++++
gt
Divide each side into equal groups
++
++++
gt
Copyright copy by Houghton Mifflin Harcourt 47 All rights reserved
The solution is x gt 2
+ + +gt
2 Model the inequality
+++++
----
+++++
+ +++++
ge
Add four +1-tiles to both sides of the mat
+++++
----
+++++
+ ++
++++
+++
++++
ge
Remove zero pairs from the left side of the mat
+++++
+++++
+ +++++
++++
ge
Divide each side into equal groups
+++++
+++++
+ +++++
++++
ge
The solution is h ge 3
+ + + +ge
3 Use inverse operations to solve the inequality
5 - p
__ 6 le 4
5 - 5 - p
__ 6 le 4 - 5
thinsp- p
__ 6 le -1
thinsp-6 ( - p
__ 6 ) ge -6 ( -1 )
p ge 6
Graph the inequality and interpret the circle and
arrow
0 1 4 5 72 3 6 8 9 10
Joshua has to run at a steady pace of at least 6 mih
4 Substitute each value for v in the inequality
3v - 8 gt 22
v = 9 v = 10 v = 11
3 ( 9 ) - 8 gt 22 3 ( 10 ) - 8 gt 22 3 ( 11 ) - 8 gt 22
Evaluate each expression to see if a true inequality
results
3 ( 9 ) - 8 gt 22 3 ( 10 ) - 8 gt
22 3 ( 11 ) - 8 gt
22
27 - 8 gt 22 30 - 8 gt
22 33 - 8 gt
22
19 gt 22 22 gt
22 25 gt
22
not true not true true
v = 11
5 Substitute each value for h in the inequality
5h + 12 le -3
h = -3 h = -4 h = -5
5 ( -3 ) + 12 le -3 5 ( -4 ) + 12 le -3 5 ( -5 ) + 12 le -3
Evaluate each expression to see if a true inequality
results
5 ( -3 ) + 12 le -3 5 ( -4 ) + 12 le
-3 5 ( -5 ) + 12 le
-3
-15 + 12 le -3 -20 + 12 le
-3 -25 + 12 le
-3
-3 le -3 -8 le
-3 -13 le
-3
true true true
h = -3 h = -4 h = -5
Copyright copy by Houghton Mifflin Harcourt 48 All rights reserved
Guided Practice
1 Remove 4 +1-tiles from both sides then divide each
side into 3 equal groups the result is x lt 3
2 Use inverse operations to solve the inequality
5d - 13 lt 32
5d - 13 + 13 lt 32 + 13
5d lt 45
5d ___ 5 lt 45 ___
5
d lt 9
Graph the inequality
20 6 84 10 12 14 16 18 20
3 Use inverse operations to solve the inequality
-4b + 9 le -7
-4b + 9 - 9 le -7 - 9
-4b le -16
-4b ____ -4
ge -16 ____ -4
b ge 4
Graph the inequality
20 6 84 10 12 14 16 18 20
4 Substitute each value for m in the inequality
2m + 18 gt - 4
m = -12 m = -11 m = -10
2 ( -12 ) + 18 gt -4 2 ( -11 ) + 18 gt -4 2 ( -10 ) + 18 gt -4
Evaluate each expression to see if a true inequality
results
2 ( -12 ) + 18 gt -4 2 ( -11 ) + 18 gt
- 4 2 ( -10 ) + 18 gt
- 4
- 24 + 18 gt -4 - 22 + 18 gt
- 4 - 20 + 18 gt
- 4
- 6 gt - 4 - 4 gt
- 4 - 2 gt
- 4
not true not true true
m = -10
5 Substitute each value for y in the inequality
- 6y + 3 ge 0
y = 1 y = 1 __ 2 y = 0
-6 ( 1 ) + 3 ge 0 -6 ( 1 __ 2 ) + 3 ge 0 -6 ( 0 ) + 3 ge 0
Evaluate each expression to see if a true inequality
results
-6 ( 1 ) + 3 ge 0 - 6 ( 1 __
2 ) + 3 ge
0 - 6 ( 0 ) + 3 ge
0
-6 + 3 ge 0 -3 + 3 ge
0 0 + 3 ge
0
-3 ge 0 0 ge
0 3 ge
0
not true true true
y = 1 __ 2
y = 0
6 Solve the inequality
65 - 4t ge 15
65 - 65 - 4t ge 15 - 65
-4t ge -5
-4t ____ -4
le -5 ___ -4
t le 125
Graph the inequality
0 05 1 15 2 25
Lizzy can spend from 0 to 125 h with each student
No 15 h per student will exceed Lizzyrsquos available
time
7 Sample answer Apply inverse operations until you
have isolated the variable If you multiply or divide
both sides of the inequality by a negative number
reverse the direction of the inequality symbol
Independent Practice
8 2s + 5 ge 49
2s + 5 - 5 ge 49 - 5
2s ge 44
2s ___ 2 ge 44 ___
2
s ge 22
10 14 1612 18 20 22 24 26 28 30
9 -3t + 9 ge -21
-3t + 9 - 9 ge -21 -9
-3t ge -30
-3t ____ -3
le -30 ____ -3
t le 10
ndash2ndash4ndash6ndash8ndash10 0 2 4 6 8 10
10 55 gt -7v + 6
55 - 6 gt -7v + 6 - 6
49 gt - 7v
49 ___ -7 lt -7v ____ -7
v gt -7
-10-9 -8 -7 -6 -5 -4 -3 -2 -1 0
11 21 1 __ 3 gt 3m - 2 2 __
3
21 1 __ 3 + 2 2 __
3 gt 3m - 2 2 __
3 + 2 2 __
3
24 gt 3m
24 ___ 3 gt 3m ___
3
8 gt m or m lt 8
0 1 4 5 72 3 6 8 9 10
12 a ___ -8
+ 15 gt 23
a ___ -8
+ 15 - 15 gt 23 - 15
a ___ -8
gt 8
-8 ( a ___ -8
) lt -8 ( 8 )
a lt -64
-70 -68 -66 -64 -62 -60
Copyright copy by Houghton Mifflin Harcourt 49 All rights reserved
13 f __ 2 - 22 lt 48
f __ 2 - 22 + 22 lt 48 + 22
f __ 2 lt 70
2 ( f __ 2 ) lt 2 ( 70 )
f lt 140
100 110 120 130 140 150
14 -25 + t __ 2 ge 50
-25 + 25 + t __ 2 ge 50 + 25
t __ 2 ge 75
2 ( t __ 2 ) ge 2 ( 75 )
t ge 150
130 140 150 160 170 180
15 10 + g ___
-9 gt 12
10 - 10 + g ___
-9 gt 12 - 10
g ___
-9 gt 2
-9 ( g ___
-9 ) lt -9 ( 2 )
g lt -18
-20 -18 -14 -12 -10-16
16 252 le -15y + 12
252 - 12 le -15y + 12 - 12
24 le - 15y
24 ____ -15
ge -15y
_____ -15
y le -16
-20 -18 -14 -12 -10-16
17 -36 ge -03a + 12
-36 - 12 ge -03a + 12 - 12
-48 ge -03a
-48 _____ -03
le -03a ______ -03
a ge 16
10 11 12 13 14 16 17 18 19 2015
18 80 - 2w ge 50
80 - 80 - 2w ge 50 - 80
- 2w ge -30
-2w ____ -2
le -30 ____ -2
w le 15
The width is a positive number no greater than
15 inches the possible widths in inches will be 10
11 12 13 14 and 15
19 Inequality 7n - 25 ge 65
7n - 25 ge 65
7n - 25 + 25 ge 65 + 25
7n ge 90
7n ___ 7 ge 90 ___
7
n ge 12 6 __ 7
Grace must wash at least 13 cars because n must
be a whole number
Focus on Higher Order Thinking
20 No Sample answer If x lt x - 1 then subtracting
x from both sides of the inequality 0 lt -1 That is
untrue so no value of x can be less than x - 1
21 a
10 3 42 5 6 7 8 9 10
b
10 3 42 5 6 7 8 9 10
c A number cannot simultaneously be less than 2
and greater than 7 Therefore there is no number
that satisfies both inequalities
d Consider the graph of x gt 2 and x lt 7
The solution includes all the numbers on the
number line so the solution set is all numbers
22 Sample answer Joseph might have reasoned that n
was first multiplied by 2 then increased by 5 to give
a result less than 13 Working backward he would
have subtracted 5 from 13 ( to get 8 ) then divided by
2 ( to get 4 ) giving n lt 4 Shawnee would have
followed these same steps but would have used a
variable and invers operations
MODULE 7
Ready to Go On
1 n + 7 lt -3
thinsp _ -7
_ -7
n lt -10
2 5p ge -30
5p
___ 5 ge -30 ____
5
p ge -6
3 14 lt k + 11
_ -11 _ -11
3 lt k
4 d ___ -3
le minus6
( -3 ) ( d ) ge ( -3 ) ( -6 )
d ge 18
Copyright copy by Houghton Mifflin Harcourt 50 All rights reserved
5 c - 25 le 25
_ +25 _ +25
c le 5
6 12 ge -3b
12 ___ -3
le -3b _____ -3
-4 le b
7 Let n be the number of minimum points Jose must
score 562 + n ge 650
Solve the inequality
562 + n ge 650
_ -562 _ -562
n ge 88
8 Let t be the number of minutes Lainey can descend
-20 - 20t ge -100
9 2s + 3 gt 15
_ -3 _ -3
2s gt 12
2s ___ 2
gt 12 ___ 2
s gt 6
10 - d ___ 12
- 6 lt 1
_ +6 _ +6
- d ___ 12
lt 7
12 ( - d ___ 12
) lt 12 ( 7 )
-d lt 84
d gt -84
11 -6w - 18 ge 36
_ +18 _ +18
thinsp-6w ge 54
-6w _____ -6
le 54 ___ -6
w le -9
12 z __ 4 + 22 le 38
_ -22 _ -22
z __ 4 le 16
4 ( z __ 4 ) le 4 ( 16 )
z le 64
13 b __ 9 - 34 lt -36
_ +34 _ +34
b __ 9 lt -2
9 ( b __ 9 ) lt 9 ( -2 )
b lt -18
14 -2p + 12 gt 8
-12 ____
-12 ____
-2p gt -4
-2p
____ -2 lt -4 ___
-2
p lt 2
15 Sample answer Look for key words or phrases
that indicate inequality such as ldquogreater thanrdquo
ldquoless thanrdquo ldquoat mostrdquo or ldquoat leastrdquo
Copyright copy by Houghton Mifflin Harcourt 51 All rights reserved
MODULE 8 Modeling Geometric Figures
Are You Ready
1 3x + 4 = 10
3x + 4 - 4 =10 - 4
3x = 6
3x ___ 3 = 6 __
3
x = 2
2 5x - 11 = 34
5x - 11 + 11 = 34 + 11
5x = 45
5x ___ 5 = 45 ___
5
x = 9
3 -2x + 5 = -9
-2x + 5 - 5 = -9 - 5
-2x = -14
-2x ____ -2
= -14 ____ -2
x = 7
4 -11 = 8x + 13
-11 - 13 = 8x + 13 - 13
-24 = 8x
-24 ____ 8 = 8x ___
8
-3 = x
5 4x - 7 = -27
4x - 7 + 7 = -27 + 7
4x = -20
4x ___ 4 = -20 ____
4
x = -5
6 1 __ 2 x + 16 = 39
1 __ 2 x + 16 - 16 = 39 - 16
1 __ 2 x = 23
( 2 ) 1 __ 2 x = ( 2 ) 23
x = 46
7 12 = 2x - 16
12 + 16 = 2x - 16 + 16
28 = 2x
28 ___ 2 = 2x ___
2
14 = x
8 5x - 15 = -65
5x - 15 + 15 = -65 + 15
5x = -50
5x ___ 5 = -50 ____
5
x = -10
9 x __ 5 = 18 ___
30
x times 30 = 5 times 18
30x = 90
30x ____ 30
= 90 ___ 30
x = 3
10 x ___ 12
= 24 ___ 36
x times 36 = 12 times 24
36x = 288
36x ____ 36
= 288 ____ 36
x = 8
11 3 __ 9 = x __
3
3 times 3 = 9 times x
9 = 9x
9 __ 9 = 9x ___
9
1 = x
12 14 ___ 15
= x ___ 75
14 times 75 = 15 times x
1050 = 15x
1050 _____ 15
= 15x ____ 15
70 = x
13 8 __ x = 14 ___ 7
8 times 7 = x times 14
56 = 14x
56 ___ 14
= 14x ____ 14
4 = x
14 14 ___ x = 2 __ 5
14 times 5 = x times 2
70 = 2x
70 ___ 2 = 2x ___
2
35 = x
15 5 __ 6 = x ___
15
5 times 15 = 6 times x
75 = 6x
75 ___ 6 = 6x ___
6
125 = x
Solutions KeyGeometry
UNIT
4
Copyright copy by Houghton Mifflin Harcourt 52 All rights reserved
16 81 ___ 33
= x ____ 55
81 times 55 = 33 times x
4455 = 33x
4455 _____ 33
= 33x ____ 33
135 = x
LESSON 81
Your Turn
6 Length 132 in times 5 ft ____ 3 in
= 22 ft
Width 6 in times 5 ft ____ 3 in
= 10 ft
Area 10 ft ( 22 ft ) = 220 square feet
Guided Practice
1
Blueprint
length (in)3 6 9 12 15 18
Actual
length (ft)5 10 15 20 25 30
a The wall is 30 feet long
b 25 ft times 3 in ____ 5 ft
= 15 in
2 The width is 7 in times 4 ft ____ 2 in
= 14 ft and the length is
14 in times 4 ft ____ 2 in
= 28 ft and the area is
28 ft ( 14 ft ) = 392 square feet
3 Length 10 cm times 5 m _____ 2 cm
= 25 m
Width 6 cm times 5 m _____ 2 cm
= 15 m
Area 25 m ( 15 m ) = 375 square meters
4 a
b Length is 36 m and width is 24 m using both
scales
5 If the scale drawing is complete and accurate you
can use it to find any length or area of the object of
the drawing
Independent Practice
6 a 2 in times 40 cm ______ 1 in
= 80 cm
15 in times 40 cm ______ 1 in
= 60 cm
The dimensions of the painting are 80 cm by 60 cm
b 80 cm times 60 cm = 4800 c m 2
c 80 cm times 1 in _______ 254 cm
asymp 315 in
60 cm times 1 in _______ 254 cm
asymp 236 in
The dimensions of the painting are approximately
315 in by 236 in
d 315 in times 236 in asymp 743 i n 2
7 120 ft times 1 unit _____ 5 ft
= 24 units
75 ft times 1 unit _____ 5 ft
= 15 units
The dimensions of the drawing are 24 units by
15 units
8 Sample answer 2 in6 ft 1 in3 ft and 1 in1 yd
9 Because the scale is 10 cm1 mm and because
10 cm is longer than 1 mm the drawing will be
larger
10 a Let r represent the scale
54 ft times r = 810 m
r = 810 m ______ 54 ft
r = 150 m ______ 1 ft
The scale is 1 ft = 150 m
b 54 ft times 12 in _____ 1 ft
= 648 in
Let b represent the number of tiny bricks
b = 648 in times 1 brick ______ 04 in
b = 162 bricks
The model is 162 tiny bricks tall
11 a Let h represent the height of the model
h = 30 ft times 126 cm _______ 1 ft
h = 378 cm
Let n represent the number of toothpicks
n = 378 cm times 1 toothpick
_________ 63 cm
n = 6 toothpicks
The model will be 6 toothpicks tall
b 378 cm times 1 swab ______ 76 cm
asymp 5 swabs
The model will be about 5 cotton swabs tall
Focus on Higher Order Thinking
12 If the area of the scale drawing is 100 square cm
then one side is 10 cm Let s represent the side
length of the actual floor
s = 10 cm times 2 ft _____ 1 cm
s = 20 ft
So the area is 20 ft(20 ft) = 400 ft 2
The ratio of areas is 100 square cm 400 square feet
or 1 square cm 4 square feet
Copyright copy by Houghton Mifflin Harcourt 53 All rights reserved
13 Decide on the new scale yoursquod like to use Then find
the ratio between the old scale and the new scale
and redraw the scale drawing accordingly For
example the ratio could be 13 In that case you
would redraw the dimensions at three times the
original size
14 Sample answer 1 __ 4 in 8 ft 40 ft by 24 feet 960 f t
2
LESSON 82
Guided Practice
1 The two angles 45deg and a right angle or 90deg with
the included side 8 cm determine the point at which
the sides meet so a unique triangle is formed
2 The sum of the measures of the two short sides
4 + 3 = 7 The sum is less than the measure of the
long side 11 so no triangle is formed
3 The two angles 40deg and 30deg with the included side
7 cm determine the point at which the sides meet
so a unique triangle is formed
4 The sum of the measures of the two short sides
6 + 7 = 13 The sum is greater than the measure of
the long side 12 so a unique triangle is formed
5 Sample answer Segments with lengths of 5 in
5 in and 100 in could not be used to form a
triangle
Independent Practice
6 A figure with side lengths of 3 centimeters and 6
centimeters and an included angle of 120deg deter-
mine the length of the third side of a triangle and so
produce a unique triangle
6 cm
3 cm120˚
7 The side lengths proposed are 15 ft 21 ft and 37 ft
The sum of the measures of the two shorter sides
15 + 21 = 36 So the sum is less than the measure
of the long side 37 No such triangle can be created
8 The three angle measures can be used to form
more than one triangle The sign and the scale
drawing are two different-sized triangles with the
same angle measures
Focus on Higher Order Thinking
9 More than one triangle can be formed Two triangles
can be created by connecting the top of the 2-in
segment with the dashed line once in each spot
where the arc intersects the dashed line The
triangles are different but both have side lengths of
2 in and 1 1 __ 2 in and a 45deg angle not included
between them
10 The third side has a length of 15 in The third side
must be congruent to one of the other two sides
because the triangle is isosceles The third side
cannot measure 6 in because 6 + 6 is not greater
than 15 So the third side must measure 15 in
LESSON 83
Guided Practice
1 triangle or equilateral triangle
2 rectangle
3 triangle
4 rainbow-shaped curve
5 Sample answer Draw the figure and the plane
Independent Practice
6 Sample answer A horizontal plane results in cross
section that is a circle A plane slanted between
horizontal and vertical results in an oval cross
section A vertical plane through the cylinder results
in a rectangle A vertical plane along an edge of the
cylinder results in a line cross section
7 You would see circles or ovals with a cone but not
with a pyramid or prism
Focus on Higher Order Thinking
8 The plane would pass through the cube on a
diagonal from the top to the bottom of the cube
9 a It is a circle with a radius of 12 in
b The cross sections will still be circles but their
radii will decrease as the plane moves away from
the spherersquos center
10 The dimensions of two faces are 12 in by 8 in two
are 8 in by 5 in and two are 12 in by 5 in the
volume is 480 in 3
11 Sample answer If you think of a building shaped like
a rectangular prism you can think of horizontal
planes slicing the prism to form the different floors
Copyright copy by Houghton Mifflin Harcourt 54 All rights reserved
LESSON 84
Your Turn
5 Supplementary angles sum to 180deg Sample answer angFGA and angAGC
6 Vertical angles are opposite angles formed by two
intersecting lines
Sample answer angFGE and angBGC
7 Adjacent angles are angles that share a vertex and
one side but do not overlap Sample answer
mangFGD and mangDGC
8 Complementary angles are two angles whose
measures have a sum of 90deg Sample answer
mangBGC and mangCGD
9 Because mangFGE = 35deg and angFGE and angBGC are
vertical angles that means mangBGC = 35deg also
Because lines _
BE and _
AD intersect at right angles
mangBGD = 90deg so mangBGC + mangCGD = 90deg which means
mangBGC + mangCGD = 90deg 35deg + x = 90deg 35deg minus 35deg + x = 90deg minus 35deg x = 55deg
mangCGD = 55deg
10 angJML and angLMN are supplementary so their
measures sum to 180deg mangJML + mangLMN = 180deg 3x + 54deg = 180deg 3x + 54deg - 54deg = 180deg - 54deg 3x = 126deg
3x ___ 3 = 126deg ____
3
x = 42deg
mangJML = 3x = 3 ( 42deg ) = 126deg
11 Sample answer You can stop at the solution step
where you find the value of 3x because the measure
of angJML is equal to 3x
Guided Practice
1 angUWV and angUWZ are complementary angles
2 angUWV and angVWX are adjacent angles
3 angAGB and angDGE are vertical angles
so mangDGE = 30deg
4 mangCGD + mangDGE + mangEGF = 180deg 50deg + 30deg + 2x = 180deg 80deg + 2x = 180deg 2x = 100deg mangEFG = 2x = 100deg
5 mangMNQ + mangQNP = 90deg 3x - 13deg + 58deg = 90deg so 3x + 45deg = 90degThen 3x = 45deg and x = 15deg mangMNQ = 3x - 13deg = 3 ( 15deg ) - 13deg = 45deg - 13deg = 32deg
6 Sample answer Let mangS = x Write and solve an
equation ( x + 3x = 180deg ) to find x then multiply the
value by 3
Independent Practice
7 Sample answer angSUR and angQUR are adjacent
They share a vertex and a side
8 Sample answer angSUR and angQUP
9 Sample answer angTUS and angQUN
10 mangQUR = 139deg Sample answer angSUR and angSUP
are supplementary so mangSUP = 180deg - 41deg = 139deg angSUP and angQUR are vertical angles so they are
congruent and mangQUR = mangSUP = 139deg
11 mangRUQ is greater Sample answer angSUR and
angNUR are complementary so
mangNUR = 90deg - 41deg = 49deg mangTUR = 41deg + 90deg which is less than
mangRUQ = 49deg + 90deg
12 Because angKMI and angHMG are vertical angles their
measures are equal
mangKMI = mangHMG
84 = 4x
84 ___ 4 = 4x ___
4
x = 21deg
13 Because angKMH and angKMI are supplementary
angles the sum of their measures is 180deg mangKMH + mangKMI = 180deg x + 84 = 180
x + 84 - 84 = 180 - 84
x = 96
mangKMH = 96deg
14 Because angCBE and angEBF are supplementary
angles the sum of their measures is 180deg mangCBE + mangEBF = 180deg x + 62 = 180
x + 62 - 62 = 180 - 62
x = 118
mangCBE = 118deg
15 Because angABF and angFBE are complementary
angles the sum of their measures is 90deg mangABF + mangFBE = 90deg x + 62 = 90
x + 62 - 62 = 90 - 62
x = 28
mangABF = 28deg
16 Because angCBA and angABF are supplementary
angles the sum of their measures is 180deg mangABF = 28deg so
mangCBA + mangABF = 180deg x + 28 = 180 - 28
x + 28 - 28 = 152
mangCBA = 152deg
Copyright copy by Houghton Mifflin Harcourt 55 All rights reserved
17 If the two angles are complementary the sum of
their angles is 90degmangA + mangB = 90deg ( x + 4deg ) + x = 90deg 2x + 4deg = 90deg _ -4deg _ -4deg 2x = 86deg
2x ___ 2 = 86deg ___
2
x = 43degBecause x = mangB then mangB = 43deg and
mangA = 43deg + 4deg so mangA = 47deg
18 If the two angles are supplementary the sum of their
angles is 180degmangD + mangE = 180deg 5x + x = 180deg 6x = 180deg
6x ___ 6 = 180deg ____
6
x = 30degBecause x = mangE then mangE = 30deg and
mangD = 30deg x 5 so mangD = 150deg
19 If the two angles are complementary the sum of
their angles is 90deg When angles are divided into
minutes and seconds one apostrophe signifies a
minute and two apostrophes signifies a second
mangJ + mangK = 90deg0000
48deg268+ mangK = 90deg0000
_ -48deg268 _ -48deg268
mangK = 41deg3352
mangK = 41deg3352 or mangK = 41 degrees
33 minutes 52 seconds
Focus on Higher Order Thinking
20 Yes a parking lot can be built because the measure
of angle K is 180deg - ( 50deg + 90deg ) or 40deg which is
greater than 38deg
21 Disagree the sum of the measures of a pair of
complementary angles is 90deg So the measure of
each angle must be less than 90deg 119deg gt 90deg
22 a The sum of mangA and its complement will be 90deg Let x represent the complement
mangA + x = 90deg 77deg + x = 90deg _ -77deg = _ -77deg x = 13deg The complement of mangA has a measure of 13deg
and a complement of a complement of mangA
would have an angle equal to mangA or 77deg b A complement of a complement of an angle has
the same measure of the angle itself Let xdeg be
the measure of an angle The measure of a
complement of the angle is ( 90 - xdeg ) A complement of that angle has a measure of
( 90 - ( 90 - xdeg ) ) = ( 90 - 90 + xdeg ) = xdeg
MODULE 8
Ready to Go On
1
Living
roomKitchen Office Bedroom Bedroom Bathroom
Actual
ℓ times w ( ft ) 16 times 20 12 times 12 8 times 12 20 times 12 12 times 12 6 times 8
Blueprint
ℓ times w ( in ) 4 times 5 3 times 3 2 times 3 5 times 3 3 times 3 15 times 2
2 No The side lengths proposed are 8 cm 4 cm and
12 cm The sum of the measures of the two shorter
sides 4 + 8 = 12 So no such triangle can be
created
3 The longest side could be 15 cm because 20 cm is
too long given the lengths of the other sides
4 A circle is a possible cross section of a sphere
A point is another
5 A circle rectangle oval and line are possible cross
sections of a cylinder
6 mangBGC and mangFGE are vertical angles so
mangFGE = 50deg
7 If the two angles are complementary the sum of
their angles is 90deg mangS + mangY = 90deg
( 2 ( mangY ) - 30deg ) + mangY = 90deg 3 ( mangY ) - 30deg = 90deg _ +30deg = _ +30deg 3 ( mangY ) = 120deg
3 ( mangY ) ________ 3 = 120deg ____
3
mangY = 40deg
mangY = 40deg
8 Sample answer You can use scale drawings to plan
rooms or gardens
Copyright copy by Houghton Mifflin Harcourt 56 All rights reserved
MODULE 9 Circumference Area and Volume
Are You Ready
1 416
_ times 13
1248
_ +thinsp4160
5408
5408
2 647
_ times thinsp04
2588
2588
3 705
_ times thinsp94
2820
_ +thinsp63450
66270
6627
4 256
_ timesthinsp049
2304
_ +thinsp10240
12544
12544
5 1 __ 2 ( 14 ) ( 10 )
7 ( 10 )
70 i n 2
6 ( 35 ) ( 35 )
1225 ft 2
7 ( 8 1 __ 2 ) ( 6 )
17 ___ 1 2 sdot 6 3 __
1
51 i n 2
8 1 __ 2 ( 125 ) ( 24 )
1 __ 2 ( 24 ) ( 125 )
( 12 ) ( 125 )
15 m 2
LESSON 91
Your Turn
3 d = 11 cm
C = πd
C asymp 314 ( 11 )
C asymp 3454
The circumference is about 3454 cm
6 C = πd
44 asymp 314d
44 ____ 314
asymp d
d asymp 1401 yards
Divide the diameter of the garden by the digging
rate
1401 divide 7 = 2001
It takes Lars about 2 hours to dig across the garden
Guided Practice
1 d = 9 in
C asymp 314 ( 9 )
C asymp 2826 in
2 r = 7 cm
C = 2πr
C asymp 2 ( 22 ___ 7 ) ( 7 )
C asymp 44 cm
3 d = 25 m
C = πd
C asymp 314 ( 25 )
C asymp 785 m
4 r = 48 yd
C = 2πr
C asymp 2 ( 314 ) ( 48 )
C asymp 3014 yd
5 r = 75 in
C = 2πr
C asymp 2 ( 314 ) ( 75 )
C asymp 471 in
6 Find the diameter
C = πd
66 asymp 314d
66 ____ 314
asymp 314d _____ 314
21 asymp d
Find the cost
Carlos needs 21 + 4 = 25 feet of rope
25 times $045 = $1125
Carlos will pay $1125 for the rope
7 Because C = π yd and C = πd d = 1 yd then
r = 05 yd
d = 1 yd
8 Because C = 788 ft and C = 2πr
2πr = 788
2πr ___ 2π
= 788 ____ 2π
r asymp 788 _______ 2 ( 314 )
r asymp 1255 ft
d = 2r asymp 2 ( 1255 ft )
d asymp 2510 ft
9 d = 2r so r = d __ 2 asymp 34 ___
2
r asymp 17 in
C = πd asymp 314 ( 34 )
C = 1068 in
Copyright copy by Houghton Mifflin Harcourt 57 All rights reserved
10 Use the formula C = πd and substitute
314 for π and 13 for the diameter
Independent Practice
11 d = 59 ft
C = πd
C asymp 314 ( 59 )
C asymp 1853 ft
12 r = 56 cm
C = 2πr
C asymp 2 ( 22 ___ 7 ) ( 56 )
C asymp 352 cm
13 d = 35 in
C = πd
C asymp ( 22 ___ 7 ) ( 35 )
C asymp 110 in
14 Sample answer In exercises 12 and 13 the radius
or diameter is a multiple of 7
15 r = 94 ft
d = 2r = 2 ( 94 )
d = 188 ft
C = πd
C asymp 314 ( 188 )
C asymp 590 ft
16 d = 475 in
r = d __ 2 = 475 ____
2
r = 2375 in
C = πd
C asymp 314 ( 475 )
C asymp 14915 in
17 d = 18 in
r = d __ 2 = 18 ___
2
r = 9 in
C = πd
C asymp 314 ( 18 )
C asymp 5652 in
18 r = 15 ft
C = 2πr
C asymp 2 ( 314 ) ( 15 ) = 942 ft
The cost for edging is C times $075 per foot
so ( 942 ) ( 075 ) = 7065 or about $707
19 C = πd
C asymp ( 22 ___ 7 ) ( 63 )
C asymp 198 ft
The distance traveled is 12 times the
circumference of the Ferris wheel so
distance = 12 ( 198 ) or about 2376 ft
20 C = πd asymp 314 ( 2 )
C asymp 628 ft
Converting km to ft
2 km sdot ( 3280 ft _______
1 km ) = 6560 ft
6560 ft
_______ 628 ft
= 104459
The wheel makes about 1045 revolutions
21 The distance your friend walks is half the
circumference of the pond
1 __ 2 C = 1 __
2 πd asymp 1 __
2 sdot 314 ( 025 ) = 03925
Your friend walks approximately 03925 mi
The difference is 03925 - 025 = 01425
Your friend walks about 014 mi farther
22 Capitol Rotunda Dimensions
Height 180 ft
Circumference 3015 ft
Radius r = C ___ 2π asymp 3015
_______ 2 ( 314 )
asymp 48 ft
Diameter d = 2r = 2 ( 48 ) = 96 ft
Focus on Higher Order Thinking
23 The length of the fence is half the circumference
plus the diameter
1 __ 2 C = 1 __
2 πd asymp 1 __
2 sdot 314 ( 30 ) = 471
The total distance is 471 + 30 = 771 ft
The total cost is the length of fence times the cost
per linear foot
( 771 ft ) ( $925 _____
ft ) = $71318
It will cost about $71318
24 The circumference of the patio is
C = πd asymp 314 ( 18 ) = 5652 ft
Converting the length of one strand of lights from
inches to feet
( 54 in ) ( 1 ft _____ 12 in
) = 45 ft
To find the number of strands of lights divide the
circumference by the length of one strand
5652 ft _______ 45 ft
= 1256
Because Sam cannot buy a fraction of a strand he
must buy 13 strands
25 The distance is the difference in the circumferences
C inner
= πd asymp 314 ( 150 ) = 471 ft
The outer diameter is 150 ft + 2 ( 2 ft ) = 154 ft
C outer
= πd asymp 314 ( 154 ) = 48356 ft
The difference is 48356 - 471 = 1256 ft
It is about 1256 ft farther
26 No The circumference of the larger gear is about
πd asymp 314 ( 4 ) = 1256 inches The circumference of
the smaller gear is about πd asymp 314 ( 2 ) = 628
inches So the circumference of the larger gear is
628 inches more than the circumference of the
smaller gear
Copyright copy by Houghton Mifflin Harcourt 58 All rights reserved
27 Pool B about 057 m or 184 ft Sample answer
24 feet asymp 732 m so the diameter of Pool B is
greater and the circumference is greater
314 ( 75 ) - 314 ( 732 ) = 314 ( 018 ) asymp 057
057 m asymp 187 ft
LESSON 92
Your Turn
4 A = π r 2 A = π ( 10 ) 2
A asymp 314 ( 10 ) 2
A asymp 314 sdot 100
A asymp 314 f t 2
Guided Practice
1 r = d __ 2 = 14 ___
2 = 7 m
A = π r 2 A = π ( 7 ) 2
A asymp 314 ( 7 ) 2
A asymp 314 sdot 49
A asymp 1539 m 2
2 A = π r 2 A = π ( 12 ) 2
A asymp 314 ( 12 ) 2
A asymp 314 sdot 144
A asymp 4522 m m 2
3 r = d __ 2 = 20 ___
2 = 10 yd
A = π r 2 A = π ( 10 ) 2
A asymp 314 ( 10 ) 2
A asymp 314 sdot 100
A asymp 314 y d 2
4 A = π r 2 A = π ( 8 ) 2
A asymp 314 ( 8 ) 2
A asymp 314 sdot 64
A asymp 20096 i n 2
5 r = d __ 2 = 12 ___
2 = 6 cm
A = π r 2 A = π ( 6 ) 2
A asymp 314 ( 6 ) 2
A asymp 314 sdot 36
A asymp 11304 c m 2
6 r = d __ 2 = 13 ___
2 = 65 in
A = π r 2 A = π ( 65 ) 2
A asymp 314 ( 65 ) 2
A asymp 314 sdot 4225
A asymp 13267 i n 2
7 C = 4π = 2πr
4π ___ 2π
= 2πr ___ 2π
r = 2
A = π r 2 A = π ( 2 ) 2
A = 4π square units
8 C = 12π = 2πr
12π ____ 2π
= 2πr ___ 2π
r = 6
A = π r 2 A = π ( 6 ) 2
A = 36π square units
9 C = π __ 2 = 2πr
π __ 2 divide 2π = 2πr ___
2π
π __ 2 sdot 1 ___
2π = r
1 __ 4 = r
A = π r 2
A = π ( 1 __ 4 ) 2 = π ( 1 ___
16 )
A = π ___ 16
square units
10 A = π r 2 = 64π
π r 2 ___ π = 64π ____ π
r 2 = 64
r = 8
C = 2πr
= 2π ( 8 )
=16π yd
11 A = π r 2
Independent Practice
12 r = d __ 2 = 10 ___
2 = 5 in
A = π r 2 A = π ( 5 ) 2
A asymp 314 ( 5 ) 2
A asymp 314 sdot 25
A asymp 785 i n 2
13 A = π r 2 A = π ( 16 ) 2
A asymp 314 ( 16 ) 2
A asymp 314 sdot 256
A asymp 80384 c m 2
14 The area of the window is half the area of a circle of
diameter 36 in
r = d __ 2 = 36 ___
2 = 18 in
A semicircle
= 1 __ 2 π r 2
A semicircle
= 1 __ 2 π ( 18 ) 2
A semicircle
asymp 1 __ 2 ( 314 ) ( 18 ) 2
A semicircle
asymp 05 sdot 314 sdot 324
A asymp 50868 i n 2
Copyright copy by Houghton Mifflin Harcourt 59 All rights reserved
15 If the point ( 3 0 ) lies on the circle and the origin is
its center the radius of the circle is 3 units
A = π r 2 A = π ( 3 ) 2
A asymp 314 ( 3 ) 2
A asymp 314 sdot 9A asymp 2826 square units
16 The difference in areas is given by
A r = 75 mi
- A r = 50 mi
π ( 75 ) 2 - π ( 50 ) 2
= π ( 7 5 2 minus 5 0 2 ) = π ( 5625 minus 2500 ) = π ( 3125 ) asymp 98125
The area of the relayed signal is about 9813 mi 2
greater
17 The area of the field which is not reached by the
sprinkler is the area of the field minus the area
reached by the sprinkler or s 2 minus π r 2 where
s = 12 m and r is the radius of the circular area The
diameter of the circle is equal to a side of the field
12 m so the radius is 12 ___ 2 = 6 m So
s 2 minus π r 2 = 1 2 2 minus π ( 6 ) 2
= 144 minus π ( 36 )
asymp 144 minus 11304 = 3096
The area not reached by the sprinkler is
approximately 3096 m 2
18 No the area of the regular pancake is 4π in 2 and the
area of the silver dollar pancake is π in 2 so the area
of the regular pancake is 4 times the area of the
silver dollar pancake
19 No the top of the large cake has an area 9 times
that of the small cake The area of the top of the
large cake is 144π in 2 and that of the small cake is
16π in 2
20 Sample answer First find the radius of the circle by
using the formula C = 2πr Then substitute the
radius into the formula for the area of a circle
21 The 18-inch pizza is a better deal because it costs
about $20
_____ π ( 9 ) 2
asymp $008 or 8 cents per square inch
while the 12-inch pizza costs about $10
_____ π ( 6 ) 2
asymp $009
or 9 cents per square inch
22 a Because the bear can walk at a rate of 2 miles
per hour and was last seen 4 hours ago the
radius of the area where the bear could be found
is given by ( 2 miles per hour ) ( 4 hours ) = 8 miles
A = π r 2 = π ( 8 ) 2
= π ( 64 )
asymp 20096
The searchers must cover an area of about
201 mi 2
b The additional area is the difference in areas of
circles with radii ( 2 miles per hour ) ( 5 hours )
= 10 miles and the original 8 miles
A new
minus A old
= π ( 10 ) 2 - π ( 8 ) 2
= π ( 1 0 2 - 8 2 ) = π ( 100 - 64 )
= π ( 36 ) asymp 11304
The searchers would have to cover about 113 mi 2
more area
Focus on Higher Order Thinking
23 No the combined area is 2π r 2 while the area of a
circle with twice the radius is 4π r 2
24 The area is multiplied by a factor of n 2
25 To find the part that is the bullrsquos-eye take the ratio of
the area of the bullrsquos-eye to that of the whole target
The radius of the bullrsquos-eye is 3 __ 2 = 15 in and
the radius of the whole target is 15 ___ 2 = 75 in
A
bullrsquos-eye ________
A whole target
=
π ( 15 ) 2 ______
π ( 75 ) 2
= ( 15 ) 2
_____ ( 75 ) 2
= 225 _____ 5625
= 004
The bullrsquos-eye is 004 or 4 of the whole target
LESSON 93
Your Turn
2 The figure can be separated into a rectangle and
two right triangles
The dimensions of the large rectangle are
length = 8 + 3 = 11 ft width = 4 ft
The dimensions of the two small triangles are
base = 3 ft height = 2 ft ( upper triangle ) base = 3 ft height = 3 ft ( lower triangle ) The area of the rectangle is
A = ℓw = 11 sdot 4 = 44 f t 2
The area of the upper triangle is
A = 1 __ 2 bh = 1 __
2 sdot 3 sdot 2 = 3 f t 2
The area of the lower triangle is
A = 1 __ 2 bh = 1 __
2 sdot 3 sdot 3 = 45 f t 2
Therefore the total area of the figure is
44 + 3 + 45 = 515 f t 2
3 The figure can be separated into a square and a
semicircle
Each side of the square is equal to 10 m
The radius of the semicircle is half the diameter
or 10 ___ 2 = 5 m
The area of the square is
A = s 2 = 1 0 2 = 100 m 2
The area of the semicircle is
A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 5 ) 2
A asymp 1 __ 2 sdot 314 sdot 25
A asymp 3925 m 2
Therefore the approximate total area of the figure is
100 + 3925 = 13925 m 2
Copyright copy by Houghton Mifflin Harcourt 60 All rights reserved
4 The composite figure is made up of a rectangle and two
semicircles which can be combined to form one circle
The dimensions of the rectangle are
length = 5 ft width = 4 ft
The diameter of the circle is 4 ft so the radius is
4 __ 2 = 2 ft
The area of the rectangle is
A = ℓw = 5 sdot 4 = 20 f t 2
The area of the circle is
A = π r 2 A asymp 314 sdot ( 2 ) 2
A asymp 314 sdot 4A asymp 1256 f t 2
The approximate total area is the sum of these
two areas
20 + 1256 = 3256 f t 2
Because the glass costs $28 per square foot
multiply the total area by the cost per square foot
( 3256 f t 2 ) ( $28 ____
f t 2 ) = $91168
It will cost about $91168 to replace the glass
Guided Practice
1 Separate the figure into a triangle a rectangle and
a parallelogram
Find the area of each figure
For triangle A = 1 __ 2 bh = 1 __
2 ( 4 ) ( 2 ) = 4
For rectangle A = ℓw = ( 5 ) ( 3 ) = 15
For parallelogram A = bh = ( 5 ) ( 3 ) = 15
Triangle 4 cm 2 rectangle 15 cm
2 parallelogram
15 cm 2
Step 3 Find the area of the composite figure
4 + 15 + 15 = 34 cm 2
The area of the irregular shape is 34 cm 2
2 Method 1
A 1 = ℓw A
2 = ℓw
= 12 sdot 9 = 20 sdot 9 = 108 = 180
Total area = 288 c m 2
Method 2
A 1 = ℓw A
2 = ℓw
= 9 sdot 8 = 12 sdot 8 = 72 = 216
Total area = 288 c m 2
3 Separate the figure into a trapezoid with h = 5 ft
b 1 = 7 ft and b 2 = 4 ft and a parallelogram with
base = 4 ft and height = 4 ft
For trapezoid A = 1 __ 2 h ( b
1 + b
2 )
A = 1 __ 2 ( 5 ) ( 7 + 4 )
A = 1 __ 2 ( 5 ) ( 11 ) = 275 f t 2
For parallelogram A = bh = ( 4 ) ( 4 ) = 16 f t 2
Find the area of the composite figure
275 + 16 = 435 ft 2
Multiply the total area by the cost per square foot to
find the cost
( 435 f t 2 ) ( $225 _____
f t 2 ) = $9788
4 The first step is separating the composite figure into
simpler figures
Independent Practice
5 Area of square A = s 2 = 2 6 2 = 676 i n 2
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 13 ) 2
A asymp 1 __ 2 sdot 314 sdot 169
A asymp 26533 i n 2
The approximate total area is the sum
676 + 26533 = 94133 in 2
6 a The floor of the closet is a composite of a
rectangle with length = 10 ft and width = 4 ft and
a triangle with base = 6 ft and height = 3 + 4 = 7 ft
Area of rectangle A = ℓw = 10 sdot 4 = 40 f t 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 6 sdot 7
A = 1 __ 2 sdot 42
A = 21 f t 2
The total area is the sum
40 + 21 = 61 f t 2
b The cost is the area multiplied by the cost per
square foot
( 61 f t 2 ) ( $250 _____
f t 2 ) = $15250
7
O 42-2-4
2
-4
y
A (-2 4) B (0 4)
C (2 1)D (5 1)
E (5 -2)F (-2 -2)
The area can be thought of as a composite of a
trapezoid and a rectangle
For trapezoid Let b 1 of the trapezoid be the
segment from the point ( -2 1 ) point C with length
4 units b 2 be from point A to point B with length
2 units and height equal to 3 units
For rectangle The corners of the rectangle are
( -2 1 ) D E and F Let the length of the rectangle
be 7 units and the width be 3 units
Area of trapezoid
A = 1 __ 2 h ( b
1 + b
2 )
A = 1 __ 2 ( 3 ) ( 4 + 2 )
A = 1 __ 2 ( 3 ) ( 6 ) = 9 square units
Copyright copy by Houghton Mifflin Harcourt 61 All rights reserved
Area of rectangle A = ℓw
A = 7 sdot 3 A = 21 square units
The total area is the sum
9 + 21 = 30 square units
8 The field is a composite of a square with side = 8 m
a triangle with base = 8 m and height = 8 m and a
quarter of a circle with radius = 8 m
Area of square A = s 2 = 8 2 = 64 m 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 8 sdot 8
A = 1 __ 2 sdot 64
A = 32 m 2
Area of quarter circle A = 1 __ 4 π r 2
A asymp 1 __ 4 sdot 314 sdot ( 8 ) 2
A asymp 1 __ 4 sdot 314 sdot 64
A asymp 5024 f t 2
The approximate total area is the sum
64 + 32 + 5024 = 14624 m 2
9 The bookmark is a composite of a rectangle with
length = 12 cm and width = 4 cm and two
semicircles which combine to form a full circle with
diameter = 4 cm so radius = 4 __ 2 = 2 cm
Area of rectangle A = ℓw = 12 sdot 4 = 48 c m 2
Area of circle A = π r 2 A asymp 314 sdot ( 2 ) 2
A asymp 314 sdot 4 A asymp 1256 c m 2
The approximate total area is the sum
48 + 1256 = 6056 cm 2
10 The pennant is a composite of a rectangle with
length = 3 ft and width = 1 ft and a triangle with
base = 1 ft and height = 1 ft
Area of rectangle A = ℓw = 3 sdot 1 = 3 f t 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 1 sdot 1
A = 1 __ 2 sdot 1
A = 05 f t 2
The area of one pennant is the sum
3 + 05 = 35 ft 2
Alex is making 12 pennants so the total area of all
12 pennants is 12 sdot 35 = 42 ft 2
The cost for the pennants will be the total area times
the fabric cost per square foot
( 42 f t 2 ) ( $125 _____
f t 2 ) = $5250
11 The area of the square is the total area minus the
area of triangle
325 ft 2 - 75 ft 2 = 25 ft 2
The area of a square is A = s 2 so s 2 = 25 f t 2
Because 5 sdot 5 = 25 the length of each side of the
square is 5 ft
Focus on Higher Order Thinking
12 The area of the garden can be found from counting
squares there are 18 full squares and 4 half-squares
for a total of 20 square units Each square unit will
grow about 15 carrots So Christina will grow about
20 ( 15 ) or 300 carrots
13 To find the length of the three sides of the square
subtract the lengths of the two sides of the triangle
from the perimeter The total length of three sides of
the square is 56 - 20 = 36 in Divide by 3 to find
that the length of one side and the base of the
triangle is equal to 12 in The total area of the figure
is the area of the square plus the area of the
triangle
Area of square A = s 2 = 1 2 2 = 144 i n 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 12 sdot 8
A = 1 __ 2 sdot 96
A = 48 i n 2
The total area is the sum
144 + 48 = 192 in 2
14 Think of the scarf as a rectangle minus two
semicircles The rectangle has length = 28 in and
width = 15 in The circle has diameter = 15 in so
its radius is 15 ___ 2 = 75 in
Area of rectangle A = ℓw = 28 sdot 15 = 420 i n 2
Area of circle A = π r 2 A asymp 314 sdot ( 75 ) 2
A asymp 314 sdot 5625
A asymp 176625 i n 2
The total area is the difference
420 - 176625 = 243375 in 2 or 243 3 __
8 i n 2
15 a The window is a composite of a square and a
semicircle Because each square in the window
has an area of 100 in 2 the length of each side is
10 in So each side of the square portion of the
entire window has length 10 sdot 4 = 40 in The
diameter of the semicircle is also 40 in so
the radius is 40 ___ 2 = 20 in
Area of square A = s 2 = 4 0 2 = 1600 i n 2
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 20 ) 2
A asymp 1 __ 2 sdot 314 sdot 400
A asymp 628 i n 2
The approximate total area is the sum
1600 + 628 = 2228 in 2
Copyright copy by Houghton Mifflin Harcourt 62 All rights reserved
b The shade is a composite of a rectangle and
a semicircle The length of the rectangle is equal
to the length of one side of the square portion
of the window plus 2 sdot 4 inches for a total of
40 + 2 sdot 4 = 48 in
The height of the rectangular portion of the shade
is equal to 4 times the length of one side of the
square portion of the window plus 4 inches for a
total of 40 + 4 = 44 in
The diameter of the semicircle at the top is the
same as the length of the bottom of the shade
48 in so the radius = 48 ___ 2 = 24 in
Area of rectangle A = ℓw = 48 sdot 44 = 2112 i n 2
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 24 ) 2
A asymp 1 __ 2 sdot 314 sdot 576
A asymp 90432 i n 2
The approximate total area of the shade is
the sum
2112 + 90432 asymp 3016 in 2
LESSON 94
Your Turn
3 Find the area of a base
B = l times w
= 9 times 2
= 18 square inches
Find the perimeter of the base
P = 2 ( 9 ) + 2 ( 2 )
= 18 + 4 = 22 inches
Find the surface area
S = Ph + 2B
S = 22 ( 1 1 __ 2 ) + 2 ( 18 )
= 33 + 36
= 69
The surface area of the box is 69 square inches
4 Find the area of the base of the larger prism
B = times w
= 12 times 12
= 144 square inches
Find the perimeter of the base
P = 4 ( 12 )
= 48 inches
Find the surface area of the larger prism
S = Ph + 2B
S = 48 ( 12 ) + 2 ( 144 )
= 576 + 288
= 864 square inches
Find the area of the base of the smaller prism
B = l times w
= 8 times 8
= 64 square inches
Find the perimeter of the base
P = 4 ( 8 )
= 32 inches
Find the surface area of the smaller prism
S = Ph + 2B
S = 32 ( 8 ) + 2 ( 64 )
= 256 + 128
= 384 square inches
Add the surface areas of the two prisms and
subtract the areas not stained (the bottom of the
larger prism and the smaller prism and an equal
area of the top of the larger prism where the smaller
prism sits) Surface area = 864 + 384 - 144 - 64
- 64 = 976 The surface area of the part of the plant
stand that she will stain is 976 square inches
Guided Practice
1 Perimeter of base = 5 + 5 + 8 = 18
Perimeter of base = 18 ft
Height = 7 ft
Base area = 1 __ 2 ( 3 ) ( 8 ) = 12 ft 2
Surface area
S = ( 18 ft ) ( 7 ft ) + 2 ( 12 ft 2 ) = 150 ft 2
2 Find the area of a base of the cube
B = l times w
= 25 times 25
= 625 m 2
Find the perimeter of the base of the cube
P = 4 ( 25 )
= 10 m
Find the surface area of the cube
S = Ph + 2B
S = 10 ( 25 ) + 2 ( 625 )
= 25 + 125
= 375
Surface area of cube
S = 375 m 2
Find the area of a base of the rectangular prism
B = l times w
= 11 times 9
= 99 m 2
Find the perimeter of the base of the rectangular
prism
P = 2 ( 11 ) + 2 ( 9 )
= 22 + 18
= 40 m
Find the surface area of the rectangular prism
S = Ph + 2B
S = 40 ( 7 ) + 2 ( 99 )
= 280 + 198
= 478
Surface area of rectangular prism
S = 478 m 2
Find the overlapping area the bottom of the cube
A = ( 25 ) ( 25 ) = 625
Overlapping area A = 625 m 2
Surface area of composite figure
= 375 + 478 -2 ( 625 ) = 503 m 2
3 Find the surface area of each of the prisms that
make up the solid Add the surface areas and
subtract the areas of any parts that are not on the
surface
Copyright copy by Houghton Mifflin Harcourt 63 All rights reserved
Independent Practice
4 Find the area of a base
B = l times w
= 10 times 3
= 30 in 2
Find the perimeter of the base
P = 2 ( 10 ) + 2 ( 3 )
= 20 + 6
= 26 in
Find the surface area
S = Ph + 2B
S = 26 ( 4 ) + 2 ( 30 )
=104 + 60
= 164 in 2
She needs 164 in 2 of wrapping paper
5 Find the area of the base
B = l times w
= 20 times 15
= 300 cm 2
Find the perimeter of the base
P = 2 ( 20 ) + 2 ( 15 )
= 40 + 30
= 70 cm
Find the surface area of the box
S = Ph + 2B
S = 70 ( 9 ) + 2 ( 300 )
= 630 + 600
= 1230 cm 2
Find the surface area of the top and sides
1230 - 300 = 930 cm 2
Find the area of a glass tile
Area of tile = 5 times 5 = 25 mm 2
Convert cm 2 to mm
2
930 cm 2 times 100 mm
2 ________
1 cm 2 = 93000 mm
2
Find the number of tiles needed
93000 divide 25 = 3720
3720 tiles are needed
6 Find the area of the L-shaped base
Area of L-shape = 2 times 1 + 3 times 1
= 2 + 3 = 5 in 2
Find the perimeter of the L-shaped base
Perimeter = 3 + 3 + 1 + 2 + 2 + 1
= 12 in
Find the surface area
S = Ph + 2B
S = 12 ( 3 ) + 2 ( 5 )
= 36 + 10
= 46 in 2
The surface area of each brace is 46 in 2
7 Find the area of the triangular prism
Perimeter = 25 + 25 + 3 = 8 ft
Base area = 1 __ 2 ( 2 ) ( 3 ) = 3 ft 2
Surface area = Ph + 2B
= 8 ( 4 ) + 2 ( 3 )
= 32 + 6 = 38 ft 2
Find the area of the rectangular prism
Perimeter = 2 ( 3 ) + 2 ( 4 ) = 14 ft
Base area = 3 times 4 = 12 ft 2
Surface area = Ph + 2B
= 14 ( 2 ) + 2 ( 12 )
= 28 + 24 = 52 ft 2
Add the surface areas of the two prisms and
subtract the parts not on the surface
Surface area = 38 + 52 - 12 - 12 = 66 ft 2
The total surface area of the doghouse is 66 ft 2
8 Treat the figure as ( 1 ) a composite of two triangular
prisms and one rectangular prism or ( 2 ) a prism
with a base that is a trapezoid
9 Find the area of the trapezoid base
Area of trapezoid = 1 __ 2 ( b
1 + b
2 ) h
1 __ 2 ( 16 + 48 ) 12 = 384 in
2
Find the perimeter of the base
P = 48 + 20 + 16 + 20 = 104 in
Find the surface area
S = Ph + 2B
S = 104 ( 24 ) + 2 ( 384 )
= 2496 + 768
= 3264 in 2
The surface area of the ramp is 3264 in 2
10 Find the area of the base of the larger prism
B = l times w
= 7 times l
= 7 ft 2
Find the perimeter of the base
P = 2 ( 7 ) + 2 ( 1 )
= 14 + 2
= 16 ft
Find the surface area of the larger prism
S = Ph + 2B
S = 16 ( 2 ) + 2 ( 7 )
= 32 + 14
= 46 f t 2
Find the area of the base of the smaller prism
B = l times w
= 1 times 1
= 1 ft 2
Find the perimeter of the base
P = 2 ( 1 ) + 2 ( 1 )
= 2 + 2 = 4 ft
Find the surface area of the smaller prism
S = Ph + 2B
S = 4 ( 3 ) + 2 ( 1 )
= 12 + 2
= 14 ft 2
Add the surface areas of the two prisms and
subtract the parts not on the surface
Surface area = 46 + 14 - 1 - 1 = 58 ft 2
The surface area of the stand is 58 ft 2
11 Find the number of cans of paint needed
58 divide 25 = 232
It takes 2 full cans and 1 partial can so 3 cans are
needed
Find the cost of 3 cans of paint
3 times 679 = 2037
No they need 3 cans which will cost $2037
Copyright copy by Houghton Mifflin Harcourt 64 All rights reserved
12 Find the area of the base of the box
B = l times w
= 27 times 24
= 648 cm 2
Find the perimeter of the base
P = 2 ( 27 ) + 2 ( 24 )
= 54 + 48
= 102 cm
Find the surface area of the box
S = Ph + 2B
S = 102 ( 10 ) + 2 ( 648 )
= 1020 + 1296
= 2316 cm 2
2316 cm 2 will be covered with paper
13 Area of the original base B = l times w
Area of the new base = 2l times 2w = 4lw = 4B
Perimeter of the original = 2l + 2w
Perimeter of the new = 2 ( 2l ) + 2 ( 2w ) =
2 ( 2l + 2w ) = 2P
Original S = Ph + 2B
New S = 2Ph + 2 ( 4B )
No Ph doubles and 2B quadruples S more than
doubles
Focus on Higher Order Thinking
14 Find the area of the base of the prism
B = l times w
= 25 times 25
= 625 ft 2
Find the perimeter of the base
P = 4 ( 25 )
= 10 ft
Find the surface area of the prism
S = Ph + 2B
S = 10 ( 35 ) + 2 ( 625 )
= 35 + 135
= 485 ft 2
Find the surface area less the area of the bottom
surface of the prism
485 - 625 = 4225 ft 2
Find what percent of the surface area less the area
of the bottom is compare to the total surface area
4225 _____ 485
times 100 asymp 87
Sample answer She would be painting about 87
of the total surface area so she will use about 87
of the total amount of paint
15
Circumference ofcircle πd = πtimes4
r = 2 in
9 in
Find the area of the circle base
A = πr 2
asymp 31 4 ( 2 ) 2 = 1256 in 2
Find the circumference of the circle
C = πd
asymp 314 ( 4 ) = 1256 in 2
Find the area of the rectangle
Area asymp 9 times 1256 = 11304 in 2
Find the surface area of the cylinder
S = Ch + 2B
asymp 1256 ( 9 ) + 2 ( 1256 ) = 13816 in 2
Round to the nearest tenth 1382 in 2
The surface area of the oatmeal box is
approximately 1382 in 2
Find the amount of cardboard for 1500 boxes
1500 times 1382 = 207300 in 2
Convert square inches to square feet and round to
the nearest whole number
( 207300 in 2 ) 1 ft 2 _______
144 in 2 asymp 1440 ft 2
It would take about 1440 ft 2 of cardboard
16 Each face has 9 squares 1 cm by 1 cm so S =
54 cm 2 The surface area stays the same when one
or more corner cubes are removed ( Fig 2 3 ) because the number of faces showing is still the
same In Fig 4 S increases because 2 more faces
show
LESSON 95
Your Turn
2 Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 24 ) 7
= 84 m 2
Find the volume of the prism
V = Bh
= ( 84 ) ( 22 )
= 1848 m 3
The volume of the prism is 1848 m 3
5 Find the base area B of the trapezoidal prism
B = 1 __ 2 ( b 1 + b 2 ) h
= 1 __ 2 ( 8 + 12 ) 10
= 1 __ 2 ( 20 ) 10 = 100 cm
2
Find the volume of the prism
V = Bh
= ( 100 ) ( 22 )
= 2200 cm 3
The volume of the prism is 2200 cm 3
7 Find the volume of each prism
Find the base area B of the rectangular prism
B = bh
= ( 13 ) 13
= 169 in 2
Find the volume of the rectangular prism
V = Bh
= ( 169 ) ( 30 )
= 5070 in 3
Copyright copy by Houghton Mifflin Harcourt 65 All rights reserved
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 9 ) 13
= 585 in 2
Find the volume of the triangular prism
V = Bh
= ( 585 ) ( 30 )
= 1755 in 3
Find the sum of the volumes
5070 + 1755 = 6825 in 3
The volume of the composite figure is 6825 in 3
Guided Practice
1 B = 1 __ 2 bh = 1 __
2 ( 8 ) ( 3 ) = 12 ft 2
V = Bh = ( 12 times 7 ) ft 3 = 84 ft 3
2 B = 1 __ 2 ( b 1 + b 2 ) h = 1 __
2 ( 15 + 5 ) 3 = 30 m
2
V = Bh = ( 30 times 11 ) m 3 = 330 m 3
3 Find the base area B of the rectangular prism
B = bh
= ( 4 ) 6 = 24 ft 2
Find the volume of the rectangular prism
V = Bh
= ( 24 ) ( 12 ) = 288 ft 3
The volume of the rectangular prism = 288 ft 3
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 6 ) 4 = 12 ft 2
Find the volume of the triangular prism
V = Bh
= ( 12 ) ( 6 ) = 72 ft 3
The volume of the triangular prism = 72 ft 3
Find the sum of the volumes
288 + 72 = 360 ft 3
The volume of the composite figure = 360 ft 3
4 Find the base area B of the rectangular prism
B = bh
= ( 40 ) ( 50 ) = 2000 ft 2
Find the volume of the rectangular prism
V = Bh
= ( 2000 ) ( 15 ) = 30000 ft 3
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 40 ) ( 10 ) = 200 ft 2
Find the volume of the triangular prism
V = Bh
= ( 200 ) ( 50 ) = 10000 ft 3
Find the sum of the volumes
30000 + 10000 = 40000 ft 3
The volume of the barn is 40000 ft 3
5 Find the base area B of the trapezoidal prism
B = 1 __ 2 ( b 1 + b 2 ) h
= 1 __ 2 ( 10 + 12 ) 5
= 1 __ 2 ( 22 ) 5 = 55 cm
2
Find the volume of the trapezoidal prism
V = Bh
= ( 55 ) ( 7 ) = 385 cm 3
The volume of the container is 385 cm 3
6 Find the volume of each prism using the formula
V = Bh Then add the volumes of all the prisms
Independent Practice
7 The area of the base of the prism is given 35 in 2
Find the volume of the prism
V = Bh
= ( 35 ) ( 5 ) = 175 in 3
The volume of the trap is 175 in 3
8 The shape of the ramp is triangular prism
Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 7 ) ( 6 ) = 21 in
2
Find the volume of the triangular prism
V = Bh
= ( 75 ) ( 7 ) = 525 in 3
The volume of the ramp is 525 in 3
9 Find the base area B of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 8 ) ( 4 ) = 16 ft 2
Find the volume of the triangular prism
V = Bh
= ( 16 ) ( 24 ) = 384 ft 3
The space contained within the goal is 384 ft 3
10 Find the base area B of the trapezoidal prism
B = 1 __ 2 ( b 1 + b 2 ) h
= 1 __ 2 ( 7 + 5 ) 4
= 1 __ 2 ( 12 ) 4 = 24 in
2
Find the volume of the trapezoidal prism
V = Bh
= ( 24 ) ( 8 ) = 192 in 3
The volume of the gift box is 192 in 3
11 Find the volume of the triangular prism
V = Bh
= ( 20 ) ( 15 ) = 300 in 3
The units for volume are incorrect the volume is
300 cubic inches
12 The area of the base of the hexagonal prism is
given B = 234 in 3
Find the volume of the hexagonal prism
V = Bh
= ( 234 ) ( 3 ) = 702 in 3
Copyright copy by Houghton Mifflin Harcourt 66 All rights reserved
Find the base area B of the rectangular prism
B = bh
= ( 3 ) ( 3 ) = 9 in 2
Find the volume of the rectangular prism
V = Bh
= ( 9 ) ( 3 ) = 27 in 3
Find the sum of the volumes
702 + 27 = 972 in 3
The volume of the figure is 972 in 3
13 Find the base area B of the larger rectangular prism
B = bh
= ( 75 ) 375 = 28125 m 2
Find the volume of the larger rectangular prism
V = Bh
= ( 28125 ) ( 75 ) asymp 21094 cm 3
Find the base area B of the smaller rectangular
prism
Find the measure of the base
15 - 75 = 75
Find the base area B of the larger rectangular prism
B = bh
= ( 75 ) 375 = 28125 m 2
Find the volume of the smaller rectangular prism
V = Bh
= ( 28125 ) ( 375 ) asymp 10547 cm 3
Find the sum of the volumes of the prisms
21094 + 10547 = 31641 m 3
The volume of the figure rounded to the nearest
hundredth is 31641 m 3
14 Find the volume of the hexagonal candle
V = Bh
= ( 21 ) ( 8 ) = 168 cm 3
Find the amount of wax Josie would have after
making the hexagonal candle
260 - 168 = 92 cm 3
Find the volume of the triangular candle
V = Bh
= ( 7 ) ( 14 ) = 98 cm 3
Find the amount of wax Josie would have after
making the hexagonal candle
260 - 168 = 92 cm 3
Find the area of the base of a triangular candle with
a height of 14 cm
V = Bh
92 = B ( 14 )
92 ___ 14
= B ( 14 ) _____ 14
6 8 ___ 14
= B asymp 657
No the area of the base of the triangular candle
must be less than or equal to about 657 cm 2
15 The base of trapezoidal prism is given 36 in 2 Find
the volume of the trapezoidal prism
V = Bh
= ( 36 ) ( 5 ) = 180 in 3
The base of triangular prism is given 32 in 2
Find the volume of the trapezoidal
prism V = Bh
= ( 32 ) ( 6 ) = 192 in 3
Triangular prism you get 192 in 3 for the same price
you would pay for 180 in 3 with the trapezoidal prism
Focus on Higher Order Thinking
16 Find the area of the base of the trapezoidal prism
V = Bh
286 = B ( 8 )
286 ____ 8 = B ( 8 )
3575 = B
Find the missing dimension of the base of the
trapezoidal prism
1 __ 2 ( 2 + b 2 ) 13 = 3575
1 __ 2 ( 2 + b 2 ) ( 13 ___
13 ) = 3575 _____
13
( 2 ) 1 __ 2 ( 2 + b 2 ) = ( 2 ) 275
2 + b 2 = 55
_ -2 _ -2
b 2 = 35 ft
The missing dimension is 35 ft
17 Find the area of the base of the triangular prism
B = 1 __ 2 bh
= 1 __ 2 ( 10 ) 6 = 30 cm
2
Find the volume of the triangular prism
V = Bh
= ( 30 ) ( 25 ) = 75 cm 3
Find the mass of the doorstop
mass asymp ( V in cm 3 ) ( 86 g
_____ cm
3 )
asymp ( 75 cm 3 ) ( 86 g
_____ cm
3 ) = 645 g
The volume of the doorstop is 75 cm 3 The mass is
about 645 g
18 If both the base and height of the triangular base are
tripled the area of the base is multiplied by 9
Tripling the height of the prism as well means the
volume of the prism is multiplied by 27
19 Use the formula for the volume of a trapezoidal
prism to find a set of dimensions that have a volume
of 120 cm 3
V = Bh
V = [ 1 __ 2 ( b 1 + b 2 ) h 1 ] h 2
120 ≟ [ 1 __ 2 ( 2 + 6 ) 4 ] 75
= [ 1 __ 2 ( 8 ) 4 ] 75
= [ 16 ] ( 75 ) = 120
Try another set of dimensions in the formula
V = Bh
V = [ 1 __ 2 ( b 1 + b 2 ) h 1 ] h 2
120 ≟ [ 1 __ 2 ( 1 + 7 ) 25 ] 12
= [ 1 __ 2 ( 8 ) 25 ] 12
= [ 10 ] 12 = 120
Copyright copy by Houghton Mifflin Harcourt 67 All rights reserved
Sample answers ( 1 ) height of trapezoid = 4 cm
base lengths = 2 cm and 6 cm height of prism
= 75 cm ( 2 ) height of trapezoid = 25 cm base
lengths = 1 cm and 7 cm height of prism = 12 cm
MODULE 9
Ready to Go On
1 r = 7 m A = π r 2 C = 2πr A asymp 314 sdot ( 7 ) 2
C asymp 2 sdot 314 sdot 7 A asymp 314 sdot 49
C asymp 4396 m A asymp 15386 m 2
2 d = 12 cm d = 6 cm so r = 12 ___ 2 = 6 ft
C = πd A = π r 2 C asymp 314 ( 12 ) A asymp 314 sdot ( 6 ) 2
C asymp 3768 cm A asymp 314 sdot 36
A asymp 11304 ft 2
3 The figure is a composite of a semicircle with
diameter = 16 m so radius is 16 ___ 2 = 8m and a
triangle with base = 16 m and height = 10 m
Area of semicircle A = 1 __ 2 π r 2
A asymp 1 __ 2 sdot 314 sdot ( 8 ) 2
A asymp 1 __ 2 sdot 314 sdot 64
A asymp 10048 m 2
Area of triangle A = 1 __ 2 bh
A = 1 __ 2 sdot 16 sdot 10
A = 1 __ 2 sdot 160
A = 80 m 2
The total area is the sum
80 + 10048 = 18048 m 2
4 The figure is a composite of a parallelogram with
base = 20 cm and height = 45 cm and a rectangle
with length = 20 cm and height = 55 cm
Area of parallelogram A = bh
A = 20 sdot 45
A = 90 c m 2
Area of rectangle
A = ℓw = 20 sdot 55 = 110 c m 2
The total area is the sum
90 + 110 = 200 cm 2
5 Find the area of the triangular base
Area of triangle = 1 __ 2 bh
1 __ 2 ( 4 ) 3 = 6 cm 2
Find the perimeter of the base
P = 3 + 4 + 5 = 12 cm
Find the surface area
S = Ph + 2B
S = 12 ( 10 ) + 2 ( 6 )
thinsp=120 + 12
thinsp= 132 cm 2
Find the volume of the prism
V = Bh
= ( 6 ) 10
= 60 cm 3
6 Find the area of the composite base formed by a
rectangle and a triangle
Area of triangle = 1 __ 2 bh
1 __ 2 ( 4 ) 15 = 3 yd 2
Area of rectangle = bh
( 4 ) 2 = 8 yd 2
Area of the composite base 3 + 8 = 11 yd 2
Find the perimeter of the composite base
P = 4 + 2 + 25 + 25 + 2 = 13 yd
Find the surface area
S = Ph + 2B
S = 13 ( 25 ) + 2 ( 11 )
thinsp= 325 + 22
thinsp= 545 yd 2
The area of the base of the pentagonal prism
is given
B = 234 yd 3
Find the volume of the prism
V = Bh
= ( 11 ) 25
= 275 yd 3
7 Sample answer You can use a composite figure to
model a room then find surface area to decide how
much paint you need to paint the room
Copyright copy by Houghton Mifflin Harcourt 68 All rights reserved
Solutions KeyStatistics
unit
5MODULE 10 Random Samples and Populations
Are You Ready
1 x ___16
=45___40
40x=720
40x ____40
=720____40
x=18
2 x __5=1__
4
4x=5
4x ___4
=5__4
x=5__4=125
3 25___10
=x ___10
125=10x
125____10
=10x ____10
125=x
4 x __6
=2__9
9x= 12
9x ___9
=12___9
x=12___9=4__
3
5 4748495152575960range=60-47=13
6 4566689121213range=13-4=9
7 95979799100106108115range=115-95=20
8 121319273539476671range=71-12=59
9 mean=3+5+7+3+6+4+8+6+9+5_________________________________10
=56
10 mean=81+94+113+67+62+75____________________________6
=82
LESSON 101
Your Turn
4 Yeseveryemployeehadanequalchanceofbeingselected
5 Thequestionisbiasedsincecatsaresuggested
6 ThequestionisnotbiasedItdoesnotleadpeopletopickaparticularseason
Guided Practice
1 Method1ASampleanswer
Random Sample of Seventh Grade Male Students
Student Shoe SizeArturo 75
Jimmy 80
Darnell 90
Ping 75
Zach 85
Jamar 80
BSampleanswer
75+80+90+75+85+80___________________________6
=485____6
asymp81
Meanasymp81
Method2ASampleanswer
Student Shoe Size Student Shoe SizeReggie 85 Ling 85
Stan 80 Marcus 90
Alejandro 90 Tio 85
BSampleanswer
85+80+90+85+90+85____________________________6
=515____6 =86
Mean=size86
2Method1producesresultsthataremorerepresentativeoftheentirestudentpopulationbecauseitisarandomsample
3 Method2producesresultsthatarelessrepresentativeoftheentirestudentpopulationbecauseitisabiasedsample
4 YesSampleanswerWhatisyourfavoritecolor
5 Selectarandomsampleofsufficientsizethatrepresentsthepopulationandaskeachparticipantunbiasedquestions
Independent Practice
6 SampleanswerPaulrsquossamplewasbiasedMaybehisfriendsstudiedmorethanothers
7 SampleanswerNancyrsquossampledidnotincludeasmanystationsThereportcouldincludestationsnationwide
8 ItisabiasedsampleStudentswhoarenrsquotontheteamwonrsquotbeselected
CopyrightcopybyHoughtonMifflinHarcourt 69 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U5M10indd 69 103113 216 AM
9 Itisbiasedbecausestudentswhoarenrsquotinthatclasswonrsquotbeselected
10 Itisarandomsamplebecauseallseventhgradershaveanequalchanceofbeingselected
11 Itisarandomsamplebecausetheorganizationselectsnamesatrandomfromallregisteredvoters
12 Itisbiasedbecausebasketballismentioned
13 Jaersquosquestionisnotbiasedsinceitdoesnotsuggestatypeofarttostudents
Focus on Higher Order Thinking
14 CollinrsquosmethodbetterrepresentstheentirestudentpopulationbecauseheusedarandomsampleKarlrsquosmethodpickedpeoplethatcouldallbefriendsthatgotofootballgamestogetherThesamplemaynotbestrepresenttheentirestudentpopulation
15 a Every10thstudentoutof600meansthatBarbarasurveyed60studentsThiswasarandomsample
b 35___60
= x ____100
xasymp58
Thepercentis58____100
=58
ItappearsreasonablebecauseBarbarausedarandomsampleandsurveyedasignificantpercentofthestudents
16 CarloiscorrectTherearemanyvalidwaystoselectarepresentativesamplefromapopulation
LESSON 102
Your Turn
5 damagedMP3sinsample
______________________sizeofsample
=damagedMP3sinpopulation
________________________sizeofpopulation
6___50
= x_____3500
6sdot70______50sdot70
= x _____3500
420_____3500
= x_____3500
x=420420damagedMP3s
Guided Practice
1
6 7 8 9 10 11 12 13 14 1550 1 2 3 4
2 Orderthedatafindtheleastandgreatestvaluesthemedianandthelowerandupperquartiles
6 7 7 107 114 4 54
Leastvalue
4
Lower quartile
4
Median
65
Upper quartile
7
Greatestvalue11
Drawaboxplot
10 1550
3 Themostcommonagesofchildrenthatusethelibraryare4and7
4 Therangeofagesofchildrenthatusethelibraryisfrom4to11
5 Themedianageofchildrenthatusethelibraryis65
6 defectivephonesinsample
______________________sizeofsample
=defectivephonesinpopulation
_________________________sizeofpopulation
4___60
= x_____4200
4sdot70______60sdot70
= x_____4200
280_____4200
= x_____4200
x=280About280smartphonesintheorderarelikelytobedefective
7 infectedelkinsample
__________________sizeofsample
=infectedelkinpopulation
____________________sizeofpopulation
8___50
= x_____4500
8sdot90______50sdot90
= x_____4500
720_____4500
= x_____4500
x=720About720elkarelikelytobeinfected
8 YoucansetupproportionsusinginformationobtainedinarandomsampleofthepopulationForinstancethenumberofdefectivepartsinabatchcanbeusedtopredicthowmanypartswillbedefectiveinadifferent-sizebatch
divide060
divide060
CopyrightcopybyHoughtonMifflinHarcourt 70 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U5M10indd 70 103113 218 AM
Independent Practice
9 number of people with mispriced item in sample
_______________________________________ size of sample
=
number of people with mispriced item in one day
_______________________________________ size of population
4 ___ 50
= x ____ 600
4 sdot 12 ______ 50 sdot 12
= x ____ 600
48 ____ 600
= x ____ 600
x = 48
About 48 people are likely to have a mispriced item
10 number of boxes with at least one broken crayon in sample
_______________________________________________ size of sample
=
total number of boxes with at least one broken crayon
___________________________________________ size of population
2 ___ 20
= x ____ 130
2 sdot 65 _______ 20 sdot 65
= x ____ 130
13 ____ 130
= x ____ 130
x = 13
About 13 boxes will have at least one broken crayon
11 number of puppies
________________ size of sample
= total number of puppies
___________________ size of population
12 ___ 60
= x _____ 1200
12 sdot 20 ______ 60 sdot 20
= x _____ 1200
240 _____ 1200
= x _____ 1200
x = 240
About 240 puppies are in all of the cityrsquos animal
shelters
12 number of hawks building nests
__________________________ size of sample
= total number of hawks
__________________ size of population
12 ___ 72
= x ______ 10800
12 sdot 150 _______ 72 sdot 150
= x ______ 10800
1800
______ 10800
= x ______ 10800
x = 1800
About 1800 hawks are building nests
13 Yes this seems reasonable because 23 + 27
_______ 2 = 25
is the median of the data
14 Order the data
11 12 12 12 13 13 13 14 14 14 15 17 18 18
19 22
The total number of marathoners is 16 and of those
12 run 13 miles or more
12 ___ 16
= x ____ 100
12 sdot 625 ________ 16 sdot 625
= x ____ 100
75 ____ 100
= x ____ 100
x = 75
No The statement should say that 75 of female
marathoners run 13 or more miles a week
15
6 7 8 9 1050 1 2 3 4
Sample answer Most students at Garland have 2 or
fewer siblings
16 The box plot should show that at least 50 of the
ages are between 20 and 40 years of age
17 Kudrey needs to find the median and the lower and
upper quartiles and plot those points He assumed
all quartiles would be equally long when each
quartile represents an equal number of data values
Focus on Higher Order Thinking
18 Yes the least and greatest data values The median
and quartiles may or may not be actual data values
depending on how many values are in the data
19 A box plot Since every number is different a dot
plot would only have one dot over each value which
doesnrsquot give much information The box plot would
show the median the range and where data values
are concentrated if in fact they are
20 The typical salary at this company is $24000 the
median Yes it is misleading the average is thrown
off by the outlier value of $79000
Copyright copy by Houghton Mifflin Harcourt 71 All rights reserved
9 a 56 + 43 + 62 + 63 + 33 + 34 + 38 + 51 + 59 + 59
___________________________________________ 10
= 498
The average is 498 palms
b 498 sdot 64 = 31872
There are about 3187 palms on the entire farm
Focus on Higher Order Thinking
10 55 + 57 + 57 + 58 + 59 + 59 + 59 + 59 + 59 + 61 + 62 + 62 + 63 + 64 + 66
_________________________________________________________________ 15
= 60
The mean height is 60 inches Yes it is a good sample generated randomly and contains about 20 of the entire
population so it should provide a good estimate of the mean height of all competitors But taking more samples to
gauge the variability among the samples would make for a more valid estimate
11 Sample answer Answers will vary based on each studentrsquos results but should be about 13 or 14
12 Sample answer The larger the size of the random sample the more likely it is to represent the population
accurately
LESSON 103
Guided Practice
1 (1 600) 20
2 50 51 600
3 No In the sample 4 numbers (38 26 31 and 31)
represent defective batteries which is 20 of the
total In the shipment 50 out of 600 or about 8 of
the batteries are defective
4 Sample answer A too-small or non-random sample
is likely to pick unrepresentative data values
Independent Practice
5 Shop A 10 ___ 50
times 500 = 100
Shop B 23 ____ 100
times 500 = 115
Shop C 7 ___ 25
times 500 = 140
Shop A sells 100 whole-wheat bagels
Shop B sells 115 whole-wheat bagels
Shop C sells 140 whole-wheat bagels
6 From most to least likely B A C Shop Brsquos sample
would be the most representative because it
contained the most bagels Shop Crsquos sample would
be the least representative because it contained the
fewest bagels
7 She could use either the Shop A or Shop B sample
Both use a sufficient number of bagels to be
reasonably accurate The sample from Shop C uses
too few bagels to be accurate
8 2 of the 20 T-shirts in the sample are below quality
standards Because 2 ___ 20
times 1000 = 100 the predic-
tion would be that about 100 of the 1000 T-shirts are
below quality standards This is 1 1 __ 3 times the actual
count of 75
Copyright copy by Houghton Mifflin Harcourt 72 All rights reserved
MODULE 10
Ready to Go On
1 The population is the customers in the companyrsquos
computer database The sample is biased because
the customers surveyed are more likely to value their
service
2 number of students who speak 3 or more languages
__________________________________________ size of sample
= total number of students ____________________ size of population
18 ____ 270
= x ______ 30330
18 sdot 337 ____
3 ________
270 sdot 337 ____ 3
= x ______ 30330
2022
______ 30330
= x ______ 30330
x = 2022
About 2022 students speak three or more
languages
3 Two of the random numbers 13 and 167 represent
defective MP3 players
simulated defective players
______________________ size of simulation
= defective players
______________ shipment
2 ___ 10
= x _____ 5000
2 middot 500 _______ 10 middot 500
= x _____ 5000
1000
_____ 5000
= x _____ 5000
x = 1000
Based on the sample about 1000 MP3 players are
defective
4 No the sample is too small compared to the size of
the shipment
5 Sample answer You can make predictions about
populations that are too large to survey
Copyright copy by Houghton Mifflin Harcourt 73 All rights reserved
MODULE 11 Analyzing and Comparing Data
Are You Ready
0875
1 8 ⟌ _
7000
_ -6 400
600
_ -560
40
_ -40
0
0875 875
08
2 5 ⟌ _
40
_ -4 0
0
08 80
025
3 4 ⟌ _
100
_ -80
20
_ -20
0
025 25
03
4 10 ⟌ _
30
_ -3 0
0
03 30
5 4 6 7 7 9 11 15 17
7 + 9
_____ 2 = 8
Median = 8
Mode = 7
6 36 37 40 43 44 49 50 51 56
Median = 44
Mode none
7 9 + 16 + 13 + 14 + 10 + 16 + 17 + 9
________________________________ 8
= 13
Mean = 13
8 108 + 95 + 104 + 96 + 97 + 106 + 94
________________________________ 7 = 100
Mean = 100
LESSON 111
Your Turn
2 Shape dot plots for field hockey players and
softball players have a similar spread
Center center of the field hockey dot plot is less
than the center for softball or basketball players
Spread dot plots for field hockey players and softball
players have a similar spread
3 The median is the middle value Listing the values
in order
1 4 4 4 5 5 5 6 6 6 6 7 7 8 11
In this case median 6 h
range 10 h
The median for internet usage is greater than the
median for exercise and the range is less than the
range for exercise
Guided Practice
1 Class A clustered around two areas
Class B clustered in the middle The dot plots
appear to have about half of the data clustered in
one area
2 Class A two peaks at 4 and 13 mi
Class B looks centered around 7 mi
3 Class A spread from 4 to 14 mi a wide gap with
no data
Class B spread from 3 to 9 mi
4 Class A
4 4 4 4 4 5 5 5 6 6 12 13 13 13 13 14 14
median 6
Class B
3 4 4 4 5 5 5 5 6 6 7 7 7 7 7 8 8 9
median 6
The median for both dot plots is 6 miles
5 Range for class A 14 - 4 = 10 mi
Range for class B 9 - 3 = 6 mi
6 The medians allow you to compare the centers
The ranges allow you to compare the spreads
Independent Practice
7 The dots have a relatively even spread with a peak
at 8 letters
8 The center of the graph is between 6 and 7 letters
9 The dots spread from 3 to 9 letters
10 The mean is the average
3 + 4 + 4 + 5 + 5 + 6 + 7 + 7 + 8 + 8 + 8 + 9
________________________________________ 12
74 ___ 12
asymp 617
Mean asymp 617
3 3 4 5 5 6 7 7 8 8 8 9
Because there are two middle values take their
average
6 + 7
_____ 2 = 13 ___
2 = 65
Median 65
Range 9 - 3 = 6
11 AL clustered in one small interval with an outlier to
the left
VA relatively uniform in height over the same
interval
Copyright copy by Houghton Mifflin Harcourt 74 All rights reserved
12 ALcenteredbetween8and9daysofrainVAcenteredaround10daysofrain
13 ALspreadsfrom1to12daysofrainanoutlierat1VAspreadsfrom8to12daysofrain
14 LynchburgVAhasmoreconsistentlevelsofrainandmorerainpermonthcomparedtoMontgomeryAL
15 GroupAclusteredtotheleftofsize9GroupBclusteredtotherightofsize9
16 OrderedvaluesforgroupA6577757575888888585913Thereare15itemsofdataSince15isoddthereisamiddlenumber8Sothereisnoneedtoaverageanyvalues
MedianforGroupAsize8OrderedvaluesforgroupB859999959595951010105105105115MedianforGroupBsize95
17 GroupArangewithoutlier=13-65=65withoutoutlier=9-65=25GroupBrange=115-85=3
18 SampleanswerGroupAcouldbechildrenandGroupBcouldbeadults
Focus on Higher Order Thinking
19 YesSampleansweronegroupoffivestudentscouldhavethefollowingnumberofpets12345Anothergroupoffivestudentscouldhavethefollowingnumberofpets13335Forbothgroupsofstudentsthemedianwouldbe3andtherangewouldbe4
20RangeanoutliergreatlyincreasestherangewhereasthemedianwillgenerallynotbegreatlyaffectedasitisinthemiddleofallthevaluesAdotplotwillshowboth
LESSON 112
Your Turn
3 SampleanswerTheboxeshavesimilarshapesalthoughGroupBhasashorterboxandshorterwhiskersGroupBrsquosmedianisgreaterthanGroupArsquosGroupBrsquosshorterboxmeansthemiddle50ofitsdataareclosertogetherthanthemiddle50ofGroupArsquos
4 SampleanswerTheshapeissimilartoStoreArsquosThemedianisgreaterthanStoreArsquosandlessthanStoreBrsquosTheinterquartilerangeisaboutthesameasStoreArsquosandlongerthanBrsquos
Guided Practice
1 Minimum72 Maximum88
2 Median79
3 Range88-72=16 IQR85-75=10
4 Themedianheightforhockeyplayersis70inthemedianheightforvolleyballplayersis74Thereforevolleyballplayershavethegreatermedianheight
5 Theminimumheightforhockeyplayersis64intheminimumheightforvolleyballplayersis67inSohockeyplayershavetheshortestplayer
6 IQRforhockeyplayers76-66=10IQRforvolleyballplayers78-68=10BothgroupshaveanIQRof10
7 SampleanswerMinimumandmaximumvaluesmedianrangeandIQRs
Independent Practice
8 CarAhasaminimumof165inandamaximumof210inCarBhasaminimumof160inandamaximumof205inCarAhasamedianof180inCarBhasamedianof185in
9 RangeofCarA210-165=45RangeofCarB205-160=45IQRofCarA195-170=25IQRofCarB200-175=25Bothcarshaverangesof45inandinterquartilerangesof25in
10 CarBhasagreatermediandistancethanCarATheinterquartilerangesarethesamesothemiddle50ofthejumpdistancesforthetwocarshavethesamevariability
11 CarAhaslessvariabilityinthelowestquarterofitsdataandgreatervariabilityinthehighestquarterofitsdataThevariabilityisreversedforCarB
12 CityBhasthelowestpriceof$400andalsohasthehighestpriceof$625
13 MedianforCityA$475MedianforCityB$450Difference475-450=$25CityAhasthehighermedianpriceanditis$25higher
14 SampleanswerCityBabout50ofcarsinCityBleaseforlessthan$450ascomparedtoonly25ofcarsinCityA
15 SampleanswerCityAhasagreatermediancarleasingcostthanCityBCityAhasagreaterIQRofcarleasingcoststhanCityBCityBhasamorepredictablecarleasingcostthanCityAforthemiddle50ofdatavalues
CopyrightcopybyHoughtonMifflinHarcourt 75 Allrightsreserved
DO NOT EDIT--Changes must be made through ldquoFile infordquo CorrectionKey=B
7_MCABESK207233_U5M11indd 75 103113 221 AM
Focus on Higher Order Thinking
16 The box plot with the longer box has more variability
in the middle 50 of the values
17 You can identify the minimum and maximum values
and the range of the data You can identify the
quartiles including the lower and upper quartiles
and the median as well as the interquartile range
Together these values help you recognize the
center of the data both the median and the middle
50 It helps you to recognize how spread out the
data are overall and how spread out the middle
50 of the values are around the median A dot
plot contains all the data values which a box plot
does not
18 Sample answer The range tells you very little but
the interquartile range tells you how closely the
middle half of the data cluster around the median
LESSON 113
Your Turn
1 Team 1
Mean
44 + 47 + 67 + 89 + 55 + 76 +85 + 80 + 87 + 69 + 47 + 58 = 804
804 divide 12 = 67
Mean absolute deviation
ǀ 44 - 67 ǀ = 23 ǀ 47 - 67 ǀ = 20
ǀ 67 - 67 ǀ = 0 ǀ 89 - 67 ǀ = 22
ǀ 55 - 67 ǀ = 12 ǀ 76 - 67 ǀ = 9
ǀ 85 - 67 ǀ = 18 ǀ 80 - 67 ǀ = 13
ǀ 87 - 67 ǀ = 20 ǀ 69 - 67 ǀ = 2
ǀ 47 - 67 ǀ = 20 ǀ 58 - 67 ǀ = 11
Mean of absolute values
23 + 20 + 0 + 22 + 12 + 9 +18 + 13 + 20 + 2 + 20 + 11 = 170
170 divide 12 asymp 142
Team 2
Mean
40 + 32 + 52 + 75 + 65 + 70 +72 + 61 + 54 + 43 + 29 + 32 = 625
625 divide 12 asymp 521
Mean absolute deviation
ǀ 40 - 521 ǀ = 121 ǀ 32 - 521 ǀ = 201
ǀ 52 - 521 ǀ = 01 ǀ 75 - 521 ǀ = 229
ǀ 65 - 521 ǀ = 129 ǀ 70 - 521 ǀ = 179
ǀ 72 - 521 ǀ = 199 ǀ 61 - 521 ǀ = 89
ǀ 54 - 521 ǀ = 19 ǀ 43 - 521 ǀ = 91
ǀ 29 - 521 ǀ = 231 ǀ 32 - 521 ǀ = 201
Mean of absolute values
121 + 201 + 01 + 229 +129 + 179 + 199 + 89 +19 + 91 + 231 + 201 = 169
169 divide 12 asymp 141
Difference in means
67 - 521 = 149
149 divide 141 asymp 11
The difference of the means is about 11 times the
MAD
2 There is much more overlap between the two
distributions
Guided Practice
1 Class 1 mean
12 + 1 + 6 + 10 + 1 + 2 + 3 +10 + 3 + 8 + 3 + 9 + 8 + 6 + 8 = 90
90 divide 15 = 6
Class 2 mean
11 + 14 + 11 + 13 + 6 + 7 + 8 + 6 +8 + 13 + 8 + 15 + 13 + 17 + 15 = 165
165 divide 15 = 11
Class 1 mean absolute deviation
ǀ 12 - 6 ǀ = 6 ǀ 1 - 6 ǀ = 5 ǀ 6 - 6 ǀ = 0
ǀ 10 - 6 ǀ = 4 ǀ 1 - 6 ǀ = 5 ǀ 2 minus 6 ǀ = 4
ǀ 3 - 6 ǀ = 3 ǀ 10 - 6 ǀ = 4 ǀ 3 - 6 ǀ = 3
ǀ 8 - 6 ǀ = 2 ǀ 3 - 6 ǀ = 3 ǀ 9 - 6 ǀ = 3
ǀ 8 - 6 ǀ = 2 ǀ 6 - 6 ǀ = 0 ǀ 8 - 6 ǀ = 2
6 + 5 + 0 + 4 + 5 + 4 + 3 + 4 +3 + 2 + 3 + 3 + 2 + 0 + 2 = 46
46 divide 15 asymp 3
Class 2 mean absolute deviation
ǀ 11 - 11 ǀ = 0 ǀ 14 - 11 ǀ = 3 ǀ 11 - 11 ǀ = 0
ǀ 13 - 11 ǀ = 2 ǀ 6 - 11 ǀ = 5 ǀ 7 - 11 ǀ = 4
ǀ 8 - 11 ǀ = 3 ǀ 6 - 11 ǀ = 5 ǀ 8 - 11 ǀ = 3
ǀ 13 - 11 ǀ = 2 ǀ 8 - 11 ǀ = 3 ǀ 15 - 11 ǀ = 4
ǀ 13 - 11 ǀ = 2 ǀ 17 - 11 ǀ = 6 ǀ 15 - 11 ǀ = 2
0 + 3 + 0 + 2 + 5 + 4 + 3 + 5 +3 + 2 + 3 + 4 + 2 + 6 + 2 = 44
44 divide 15 asymp 3
2 Difference in means
11 minus 6 = 5
5 divide 3 asymp 167
3 Sample answer The variation and overlap in the
distributions make it hard to make any convincing
comparison
4 To see how statistical measures vary among the
different samples
Independent Practice
5 23 + 38 + 39 + 48 + 55 + 56 + 71 +86 + 57 + 53 + 43 + 31 = 600
600 divide 12 = 50
ǀ 23 - 50 ǀ = 27 ǀ 38 - 50 ǀ = 12
ǀ 39 - 50 ǀ = 11 ǀ 48 - 50 ǀ = 2
ǀ 55 - 50 ǀ = 5 ǀ 56 - 50 ǀ = 6
ǀ 71 - 50 ǀ = 21 ǀ 86 - 50 ǀ = 36
ǀ 57 - 50 ǀ = 7 ǀ 53 - 50 ǀ = 3
ǀ 43 - 50 ǀ = 7 ǀ 31 - 50 ǀ = 19
27 + 12 + 11 + 2 + 5 + 6 + 21 +36 + 7 + 3 + 7 + 19 = 156
156 divide 12 = 13
The mean is 50degF and the MAD is 13degF
Copyright copy by Houghton Mifflin Harcourt 76 All rights reserved
6 ǀ 23 - 8 ǀ = 15 ǀ 38 - 23 ǀ = 15
ǀ 39 - 24 ǀ = 15 ǀ 48 - 33 ǀ = 15
ǀ 55 - 40 ǀ = 15 ǀ 56 - 41 ǀ = 15
ǀ 71 - 56 ǀ = 15 ǀ 86 - 71 ǀ = 15
ǀ 57 - 42 ǀ = 15 ǀ 53 - 38 ǀ = 15
ǀ 43 - 28 ǀ = 15 ǀ 31 - 16 ǀ = 15
The difference between each average monthly
temperature for City 1 and the corresponding
temperature for City 2 is 15degF
7 50 - 15 = 35
The mean is 35degF and the MAD is 13degF The
mean for City 2 must be 15degF less than the mean
for City 1 and the MAD must be the same
8 50 - 35 = 15
15 divide 13 asymp 12
The difference in the means as a multiple of the
mean absolute deviations is about 12
9
0 4 8 12 16 20 24 28 32 36 40 44
Medians
School B
School A
0 4 8 12 16 20 24 28 32 36 40 44
Means
School B
School A
Both distributions show longer travel times for school
A The distributions of the medians show less
overlap so it is more convincing
10 State A 48 - 38 = 10
10 divide 6 asymp 17
State B 50 - 42 = 8
8 divide 4 = 2
Sample answer The difference in ages is more
significant for State A if you look at the difference in
mean ages but the difference in mean ages is more
significant in State B if you consider variability as
well
11 Smiths Range 70 - 64 = 6
Median 665
Thompsons Range 80 - 74 = 6
Median 77
77 - 665 = 105
105 divide 6 = 175
The difference in the medians is 175 times the
ranges
Focus on Higher Order Thinking
12 Sample answer Jill can reasonably expect the
median of the medians of the samples to be 35
The median of the medians should be close to the
median of the population which should be 35
The outcomes are equally likely
13 Sample answer Ramonrsquos results should produce
more reliable inferences The larger the sample
size the less variability there should be in the
distributions of the medians and means
14 Sample answer Sethrsquos statement is incorrect for any
situation in which the MADs of the population are
not very similar
MODULE 11
Ready to Go On
1 The mean for the start of the school year is given by
5 + 6 + 6 + 7 + 7 + 7 + 7 + 8 + 8 + 8 + 8 + 9 + 9 + 10
________________________________________________ 14
= 105 ____ 14
= 75 mi
The mean for the end of the school year is given by
6 + 6 + 7 + 7 + 8 + 8 + 8 + 8 + 9 + 9 + 9 + 10 + 10 + 10
__________________________________________________ 14
= 115 ___ 14
asymp 82 mi
In summary Start 75 mi End about 82 mi
2 The median is the middle value
List of ordered values for start of school year
5 6 6 7 7 7 7 8 8 8 8 9 9 10
Because there are two middle values take their
average
7 + 8
_____ 2 = 15 ___
2 = 75
Median 75
List of ordered values for end of school year
6 6 7 7 8 8 8 8 9 9 9 10 10 10
Because there are two middle values we would
generally take their average but since they are both
the same and equal to 8
Median 8
Therefore Start 75 mi End 8 mi
3 Range for start of school year 10 - 5 = 5 mi
Range for end of school year 10 - 6 = 4 mi
Therefore Start 5 mi End 4 mi
4 Median for Airplane A 210 in
Median for Airplane B 204 in
Airplane A has a greater median flight length
5 IQR for Airplane A 225 - 208 = 17 in
IQR for Airplane B 230 - 195 = 35 in
Airplane B has a greater interquartile range
Copyright copy by Houghton Mifflin Harcourt 77 All rights reserved
6 The means for the shade plants
7 + 11 + 11 + 12 + 9 + 12 + 8 + 10
______________________________ 8
= 10
The means for the sun plants
21 + 24 + 19 + 19 + 22 + 23 + 24 + 24
__________________________________ 8 = 22
Range of the shade plants 12 - 7 = 5
Range of the sun plants 24 - 19 = 5
Difference in the means 22 - 10 = 12
12 ___ 5
= 24
The difference in the means is 24 times the ranges
7 Sample answer By graphing real-world data you
can identify similarities and differences in related
groups
Copyright copy by Houghton Mifflin Harcourt 78 All rights reserved
MODULE 12 Experimental Probability
Are You Ready
1 6 ___ 10
= 6 divide 2 ______ 10 divide 2
= 3 __ 5
2 9 ___ 15
= 9 divide 3 ______ 15 divide 3
= 3 __ 5
3 16 ___ 24
= 16 divide 8 ______ 24 divide 8
= 2 __ 3
4 9 ___ 36
= 9 divide 9 ______ 36 divide 9
= 1 __ 4
5 45 ___ 54
= 45 divide 9 ______ 54 divide 9
= 5 __ 6
6 30 ___ 42
= 30 divide 6 ______ 42 divide 6
= 5 __ 7
7 36 ___ 60
= 36 divide 12 _______ 60 divide 12
= 3 __ 5
8 14 ___ 42
= 14 divide 14 _______ 42 divide 14
= 1 __ 3
075
9 4 ⟌ _
300
_ -2 80
20
_ -20
0
075
0875
10 8 ⟌ _
7000
_ -6400
600
_ -560
40
_ -40
0
0875
015
11 20 ⟌ _
300
_ -2 00
100
_ -100
0
015
038
12 50 ⟌ _
1900
_ -15 00
4 00
_ -4 00
0
038
13 67 = 67 ____ 100
= 067
14 31 = 31 ____ 100
= 031
15 7 = 7 ____ 100
= 007
16 146 = 100 + 46
= 100 ____ 100
+ 46 ____ 100
= 1 + 046
= 146
17 013 = 13
18 055 = 55
19 008 = 8
20 116 = 116
LESSON 121
Your Turn
3 Because every other number from 1 through 16 is
even choosing an even number is as likely as not
and the probability is 1 __ 2
4 There are 20 possible outcomes when picking a
marble from the jar There are 10 purple marbles
Therefore the probability of picking a purple marble
is 10 ___ 20
or 1 __ 2
5 There are 6 possible outcomes when rolling a cube
There are 2 numbers greater than 4 that can be
rolled 5 and 6 Therefore the probability of rolling a
number greater than 4 is 2 __ 6 or 1 __
3
Solutions KeyProbability
UNIT
6
Copyright copy by Houghton Mifflin Harcourt 79 All rights reserved
7 P(event) + P(complement) = 1
P(5) + P(not 5) = 1
1 __ 8 + P(not 5) = 1
P(not 5) = 7 __ 8
The probability of picking a marble that is not 5 is 7 __ 8
8 P(event) + P(complement) = 1
P(even) + P(odd) = 1
1 __ 2 + P(odd) = 1
P(odd) = 1 __ 2
The probability of rolling an odd number is 1 __ 2
Guided Practice
1 The cards are numbered 1 2 3 4 5 6 7 8 9 10
You pick a number greater than 0 8
You pick an even number 5
You pick a number that is at least 2 7
You pick a number that is at most 0 1
You pick a number divisible by 3 3
You pick a number divisible by 5 2
You pick a prime number 4
You pick a number less than the
greatest prime number 6
2 There are no green playing cards in a standard
deck so randomly picking a green card is
impossible 0
3 There are as many red cards as black cards in a
standard deck so it is as likely as not 1 __ 2
4 All of the numbers are less than 12 so they are also
less than 15 The probability is certain 1
5 There are only two numbers between 1 and 12 that
are divisible by 5 5 and 10 Therefore the probability
is unlikely close to 0
6 There are 5 possible outcomes when spinning the
spinner There are two even numbers 2 and 4
Therefore the probability of the spinner landing on
an even number is 2 __ 5
7 There are 52 possible outcomes when picking a
card from a standard deck There are 13 cards with
diamonds Therefore the probability of picking a
card with a diamond is 13 ___ 52
= 1 __ 4
8 P(event) + P(complement) = 1
P(5) + P(not 5) = 1
1 __ 6 + P(not 5) = 1
P(not 5) = 5 __ 6
The probability of not rolling 5 is 5 __ 6
9 P(event) + P(complement) = 1
P(blue) + P(not blue) = 1
1 __ 3 + P(not blue) = 1
P(not blue) = 2 __ 3
The probability of not landing on blue is 2 __ 3
10 P(event) + P(complement) = 1
P(4) + P(not 4) = 1
1 __ 5 + P(not 4) = 1
P(not 4) = 4 __ 5
The probability of not landing on 4 is 4 __ 5
11 P(event) + P(complement) = 1
P(queen) + P(not queen) = 1
4 ___ 52
+ P(not queen) = 1
P(not blue) = 48 ___ 52
= 12 ___ 13
The probability of not picking a queen is 12 ___ 13
12 Sample answer pulling a red marble out of a bag
that contains only blue marbles pulling a white
marble out of a bag that contains only white marbles
Independent Practice
13 There are 52 possible outcomes when picking from
a standard deck of cards There are 8 cards that
have an ace or a king Therefore the probability of
selecting
an ace or a king is 8 ___ 52
or 2 ___ 13
14 P(event) + P(complement) = 1
P(apple or peach) + P(not apple or peach) = 1
9 ___ 12
+ P(not apple or peach) = 1
P(not apple or peach) = 3 ___ 12
or 1 __ 4
Therefore the probability of picking a piece of fruit
that is not an apple or a peach is 3 ___ 12
or 1 __ 4
15 No it is unlikely that she will have oatmeal for
breakfast Since there are 4 choices the probability
that she will choose oatmeal is 1 __ 4 or 25
16 Purple There are a lot more plants with purple
flowers than with white flowers The probability of
selecting a white-flowered plant is 2 __ 9 while the
probability of selecting a purple-flowered plant is 7 __ 9
17 Because she has more colored T-shirts than white
T-shirts it is likely that she will pick a colored T-shirt
She has 14 total T-shirts and 10 of the shirts are
colored Therefore the probability she will choose a
colored T-shirt is 10 ___ 14
or 5 __ 7
18 1 None of the students in the class have red hair so
it is certain that a randomly chosen student will not
have red hair
Copyright copy by Houghton Mifflin Harcourt 80 All rights reserved
19 a There are 14 total coins and 8 blue coins so the
probability that the coin is blue is 8 ___ 14
or 4 __ 7
b Removing 1 of the 8 blue coins leaves 7 blue
coins Adding 3 more to the 6 red coins makes
9 red coins The total of coins in the bag is now
16 Therefore the probability of choosing a red
coin is 9 ___ 16
c Removing 1 of the 6 red coins leaves 5 red coins
Adding 3 to the 8 blue coins makes 11 blue coins
The total of coins in the bag is now 16 Therefore
the probability of choosing a red coin is 5 ___ 16
Focus on Higher Order Thinking
20 Sample answer If some marbles in a jar are heavier
than others then the heavier marbles would sink
and be less likely to be selected
21 Yes Because there are only two colors selecting
not black is equal to selecting red So
P(not black) + P(black) =P(not black) + P(not red) = 1
22 2 is the number of ways the event can happen 7 is
the number of outcomes in the sample space
landing on blue
LESSON 122
Your Turn
7 The total number of spins is 6 + 14 + 10 = 30
Red 10 ___ 30
= 1 __ 3
Yellow 14 ___ 30
= 7 ___ 15
Blue 6 ___ 30
= 1 __ 5
8 Sample answer Let 1 and 2 represent blue 3 and 4
represent white and 5 and 6 represent blue Toss
the cube 50 times to determine the experimental
probability for each color Predict the next ball will be
the color with the greatest experimental probability
Guided Practice
1 The total number of spins is 14 + 7 + 11 + 8 = 40
A 14 ___ 40
= 7 ___ 20
= 035 = 35
B 7 ___ 40
= 0175 = 175
C 11 ___ 40
= 0275 = 275
D 8 ___ 40
= 1 __ 5 = 020 = 20
2 Sample answer Write ldquoyesrdquo on 6 cards and ldquonordquo on
4 cards Draw a card at random 50 times Use the
number of ldquoyesrdquo cards drawn as the prediction
3 Use an experiment to find the number of times the
event occurs for a certain number of trials
Independent Practice
4 6 ___ 10
or 3 __ 5 It is reasonable to assume that Dreersquos
past performance is an indicator of her future
performance There is no way to accurately
represent 3 __ 5 on a number cube with 6 faces
5 Sample answer Compare the number of wins to the
total number of trials
number of wins _________________ total number of trials
= 8 ___ 48
= 1 __ 6
6 There are 20 possible outcomes when picking a
name Ryan is 1 person Therefore the probability
he is chosen is 1 ___ 20
and the probability he is not
chosen is 19 ___ 20
P(Ryan) + P(not Ryan) = 1
1 ___ 20
+ P(not Ryan) = 1
P(not Ryan) = 19 ___ 20
7 Yes because it is based on actual data of weather
patterns
8 Joan Mica hit the ball 8 ___ 48
times or about 17 of her
times at bat Meanwhile Joan hit the ball 12 ___ 40
times
or 30 of her times at bat Therefore Joan has the
greater experimental probability and is more likely to
get a hit next time
9 Gabbyrsquos experimental probability of hitting an ace
is 4 ___ 10
or 2 __ 5 Gabby could serve 16 aces in her next
40 serves because 2 __ 5 of 40 is 16
10 The experimental probability her dog wonrsquot want to
go outside is 5 ___ 12
or about 417
P(outside) + P(not outside) = 1
7 ___ 12
+ P(not outside) = 1
P(not outside) = 5 ___ 12
or 417
Focus on Higher Order Thinking
11 She did not add 40 and 60 to find the total number
of trials P(heads) = 40 ____ 100
12 Sample answer coin toss Heads represents male
and tails represents female Toss the coin 50 times
and use the results to make a prediction
13 Sample answer Make an index card to represent
each coin then pick one card at random No since
the coins are different sizes they do not each have
the same probability of getting pulled out of my
Copyright copy by Houghton Mifflin Harcourt 81 All rights reserved
LESSON 123
Your Turn
1 P(coffee + small) = number of coffee + small
_____________________ total number of orders
= 60 ____ 400
= 3 ___ 20
= 15
3 P(goId + 20 in) = number of gold + 20 in
_________________________ total number of necklaces sold
= 12 ___ 75
or 4 ___ 25
Guided Practice
1 P(female + age 22ndash39)
= number of female + age 22ndash39
__________________________ total number of patients
= 50 ____ 400
or 1 __ 8
2 Sample answer There are six possible outcomes
standard with vacuum standard with no vacuum
deluxe with vacuum deluxe with no vacuum
superior with vacuum and superior with no vacuum
Students could write the outcomes on six index
cards and put them in a box Then they can draw a
card 50 times record the results and find the
experimental probability that a customer chooses a
deluxe wash with no vacuum by dividing the
frequency of this compound event by 50 the total
number of trials
3 Find the number of occurrences of the compound
event and divide it by the total number of trials
Independent Practice
4 Divide the number of 2 piece + salad orders 33 by
the total number of orders 330
P = number of 2 piece + salad
______________________ total number of orders
= 33 ____ 330
= 1 ___ 10
5 P = number of red notebooks + 150 pages
_______________________________ total number of notebooks sold
= 60 ____ 400
= 3 ___ 20
6 P(red notebook) = number of red notebooks _____________________ total number of notebooks
= 55 + 60 + 23
____________ 400
= 138 ____ 400
= 69 ____ 200
7 12 the total is the product of 3 page-count choices
and 4 color choices
8 She left out the 53 students that read 150 pages
P(7th grade + 100 pages) = 85 ____ 250
= 17 ___ 50
9 Sample answer 8th grade the results table
suggests 8th grade students are the least likely to
have read 150 pages compared to students in 6th or
7th grade
Focus on Higher Order Thinking
10 Greater heads occurs on about half the occasions
that you roll a 6 so the compound event is half as
likely
11 Sample answer For 2 outcomes he could use even
and odd numbers For 3 outcomes he could use
1 or 2 3 or 4 and 5 or 6 For 6 outcomes he could
use each number once
12 P(male + open toe) = 11 ____ 300
P(male has open toe) = 11 ____ 150
No the first scenario
includes females and the second does not
13 No because coins are fair and the probabilities do
not appear to be equally likely
14 Sample answer On a coin heads = male and
tails = female On a number cube (1 or 2) = 6th
grade (3 or 4) = 7th grade and (5 or 6) = 8th
grade Toss the coin and roll the number cube 50
times each Record the number of outcomes that are
heads and 3 or 4
LESSON 124
Your Turn
1 024 times 550 =132 customers
2 No About 371 of the emails out of 12372 will come
back undelivered because 003 times 12372 asymp 371 The
editorrsquos prediction is too high
3 024 times 350 = 84 customers Yes because 107
customers buying two or more pairs would be more
than only 84 customers
Guided Practice
1 030 times 50 = 15 times
2 015 times 365 asymp 55 days
3 No about 1009 of the candles out of 16824 will be
returned because 006 times 16824 asymp 1009
A prediction of 812 is too low
4 No about 746 toys out of 24850 will be defective
because 003 times 24850 asymp 746 A prediction of 872 is
too high
5 98 ____ 100
= x ___ 40
= 39 ___ 40
or 39 times
No if she were late 6 out of 40 times the rate of
being on time would be only 85 in which case the
light-railrsquos claim of 98 is too high
6 18 ____ 100
= x _____ 5000
= 900 _____ 5000
or 900 students Yes the
collegersquos claim is close to the number actually
accepted
times04
times04
times50
times50
Copyright copy by Houghton Mifflin Harcourt 82 All rights reserved
7 Solve a proportion using the experimental probability
to find an expected number of events to happen
Make a prediction based on the expected number of
events
Independent Practice
8 4 ____ 100
= x ____ 200
= 8 ____ 200
or 8 students More students
moved than expected because 12 is more than 8
9 Yes 6th grade 2 ____ 100
= x ____ 250
= 5 ____ 250
or 5 students
7th grade 4 ____ 100
= x ____ 200
= 8 ____ 200
or 8 students
8th grade 8 ____ 100
= x ____ 150
= 12 ____ 150
or 12 students
Since 5 + 8 + 12 = 25 the values in the table
support his claim of 30 students
10 6 ____ 100
= x ____ 300
= 18 ____ 300
or 18 seats If an airplane is
overbooked with 310 passengers only 291 are
expected to show up since 310 times 94 asymp 291
11 006 times 600 = 36 clients If 40 clients did not pay it
would be slightly more than average
12 080 times 20 = 16 team members The coachrsquos claim is
not accurate because the average number of
students at practice is 144 ____ 8 = 8
13 He set up the fraction incorrectly it should be
1 ___ 30
= x ____ 180
Focus on Higher Order Thinking
14 1 __ 2 of 12 = 6 normal rejection rate
500 times 6 = 30 transactions rejected by a
normal gas pump
15 098 times 15000 = 14700 on-time flights Sample
answer No one week of data could be misleading
and not representative of the yearly on-time prob-
ability (because it ignores bad weather etc)
16 Sample answer No They could expect to get 96
responses with the old letter since
4 ____ 100
= x _____ 2400
= 96 _____ 2400
or 96 letters Therefore the
new letter received fewer responses
MODULE 12
Ready to Go On
1 H1 H2 T1 T2
2 6 ___ 10
= 3 __ 5
3 13 ___ 20
4 3 of the 7 total trials resulted in a sum more than 5
Therefore the experimental probability is 3 __ 7
5 I would predict he would reach first base 24 times
because 3 ___ 10
= x ___ 80
= 24 ___ 80
or 24 times
6 You can use the experimental probability based on
observation or simulation to set up a proportion and
use the proportion to predict a value
times15
times15
times24
times24
times2
times2
times3
times3
times2
times2
times25
times25
times8
times8
Copyright copy by Houghton Mifflin Harcourt 83 All rights reserved
MODULE 13 Theoretical Probability and
Simulations
Are You Ready
075
1 4 ⟌ _
300
_ -2 80
20
_ -20
0
075 = 75
04
2 5 ⟌ _
20
_ -2 0
0
04 = 40
09
3 10 ⟌ _
90
_ -9 0
0
09 = 90
035
4 20 ⟌ _
700
_ -6 00
1 00
_ -1 00
0
035 = 35
0875
5 8 ⟌ _
7000
_ thinsp-6 400
600
_ -560
40
_ -40
0
0875 = 875
005
6 20 ⟌ _
100
_ -1 00
0
005 = 5
076
7 25 ⟌ _
1900
_ -17 50
1 50
_ -1 50
0
076 = 76
046
8 50 ⟌ _
2300
_ -20 50
3 00
_ -3 00
0
046 = 46
9 1 - 1 __ 5 = 5 __
5 - 1 __
5
= 4 __ 5
10 1 - 2 __ 9 = 9 __
9 - 2 __
9
= 7 __ 9
11 1 - 8 ___ 13
= 13 ___ 13
- 8 ___ 13
= 5 ___ 13
12 1 - 3 ___ 20
= 20 ___ 20
- 3 ___ 20
= 17 ___ 20
13 8 ___ 15
times 5 __ 8 =
18 ___ 315
times 5 1 ___
8 1
= 1 __ 3
14 2 __ 9 times 3 __
4 =
12 __ 39
times 3 1 ___
4 2
= 1 __ 6
15 9 ___ 16
times 12 ___ 13
= 9 ___ 416
times 12 3 _____
13
= 27 ___ 52
16 7 ___ 10
times 5 ___ 28
= 17 ___
210 times 5
1 ____
28 4
= 1 __ 8
LESSON 131
Your Turn
2 The probability of an event is the ratio of the number
of ways the event can occur to the total number of
equally likely outcomes Therefore
P(rolling a 3 or 4) =
number of sides with 3 or 4 ________________________ total number of sides on cube
= 2 __ 6 = 1 __
3
3 The total number of outcomes in the sample space
is the denominator of the formula for theoretical
probability
Copyright copy by Houghton Mifflin Harcourt 84 All rights reserved
Guided Practice
1
Basket A Basket B
Total number of outcomes5 + 3 + 8
= 16
7 + 4 + 9
= 20
Number of red balls 3 4
P(win) =
Number of red balls
_____________________ Total number of outcomes
3 ___
16 4 ___
20 = 1 __
5
2 To compare the two probabilities of 1 __ 5 and 3 ___
16 use
the least common denominator of 80
1 __ 5 = 16 ___
80
3 ___ 16
= 15 ___ 80
Therefore 16 ___ 80
gt 15 ___ 80
so 1 __ 5 gt 3 ___
16
Choosing Basket B gives you a better chance of
winning
3 There are a total of 6 odd sections The total number
of sections (odd and even) is 11
P(odd) = number of odd sections ____________________ total number of sections
= 6 ___ 11
4 There are a total of 5 even sections The total
number of sections (odd and even) is 11
P(even) = number of even sections ____________________ total number of sections
= 5 ___ 11
5 The total number faces on a number cube is 6 and
rolling either a 3 or 4 is equal to 2 possibilities
P(rolling a 3 or 4) = number of sides with 3 or 4 ________________________ total number of sides on cube
= 2 __ 6 = 1 __
3
6 Sample answer No but it might be reasonably
close
7 Divide the number of ways the event can occur
by 20
Independent Practice
8 P(yellow) = number of yellow sections
_____________________ total number of sections
= 2 __ 6
= 1 __ 3 033 or 33
9 P(blue or green) = number of blue or green sections
___________________________ total number of sections
= 8 ___ 12
= 2 __ 3 067 or 67
10 P(cherry) = number of cherry cough drops
_________________________ total number of cough drops
= 4 ___ 14
= 2 __ 7 029 or 29
11 P(black card) = number of black cards __________________ total number of cards
= 26 ___ 52
= 1 __ 2 050 or 50
12 P(lime) = number of limes ________________________ total number of pieces of fruit
= 12 - 5 ______ 12
= 7 ___ 12
058 or 58
13 There are a total of 20 DVDs There are 12 DVDs
that are not comedies (5 science fiction plus
7 adventure)
P(not a comedy)
= number of DVDs which are not comedies _________________________________ total number of DVDs
= 5 + 7 _________
5 + 7 + 8 = 12 ___
20
= 3 __ 5 060 or 60
14 There are a total of 6 faces on a number cube There
are 2 faces (3 and 4) that are greater than 2 and
less than 5 which means 2 possibilities
P(greater than 2 and less than 5)
= number of sides with 3 and 4 ________________________ total number of sides on cube
= 2 __ 6
= 1 __ 3 033 or 33
15 9 represents the ways the event can occur
13 represents the number of equally likely outcomes
16 There are a total 16 coins and there are 6 coins that
are greater than 5 cents Therefore
P(coin worth more than 5 cents)
= number of coins worth more than 5 cents _________________________________ total number of coins
= 6 ___ 16
or 3 __ 8
The event is choosing a dime or a quarter and 6 of
the 16 coins are dimes or quarters
Focus on Higher Order Thinking
17 Sample answer Riley divided the number of petunia
seeds by the number of begonia seeds rather than
the total number of seeds The correct probability is
5 ______ 5 + 15
= 5 ___ 20
= 1 __ 4
times16
times16
times5
times5
Copyright copy by Houghton Mifflin Harcourt 85 All rights reserved
18 a The total number of students in the club is 35
There are 20 seventh graders Therefore
P(seventh grader) =
number of seventh graders
______________________ total number of students
= 20 ___ 35
= 4 __ 7
There are 15 eighth graders in the club Therefore
P(eighth grader) =
number of eighth graders
_____________________ total number of students
= 15 ___ 35
= 3 __ 7
Because 4 __ 7 gt 3 __
7 choosing a seventh grader is
more likely
b No each student has the same probability of
being selected 1 ___ 35
19 Sample answer The number of trials is twice the
number of marbles in the jar If the probabilities for
each color were the same the number of times that
color was drawn would be twice the number of
marbles with that color in the jar
20 Red The theoretical probability of choosing red is
P(red) = number of red marbles ___________________ total number of marbles
= 8 ___ 20
The experimental probability of choosing red is
14 ___ 40
or 7 ___ 20
Therefore the difference in the theoretical probability
and experimental probability of choosing a red
marble is 8 ___ 20
- 7 ___ 20
= 1 ___ 20
For blue the theoretical probability is
P(blue) = number of blue marbles ____________________ total number of marbles
= 10 ___ 20
The experimental probability is 16 ___ 40
= 8 ___ 20
Therefore the difference in the theoretical probability
and experimental probability of choosing a blue
marble is 10 ___ 20
- 8 ___ 20
= 2 ___ 20
= 1 ___ 10
For yellow the theoretical probability is
P(yellow) = number of yellow marbles
_____________________ total number of marbles
= 2 ___ 20
The experimental probability is 10 ___ 40
= 5 ___ 20
Therefore the difference in the theoretical probability
and experimental probability of choosing a yellow
marble is 5 ___ 20
- 2 ___ 20
= 3 ___ 20
Choosing a red marble has the smallest difference
between theoretical and experimental probability
LESSON 132
Your Turn
3 P(ham sandwich) =
number of combinations containing ham
_________________________________ total number of sandwich combinations
= 4 ___ 12
= 1 __ 3
4 P(sandwich containing Swiss cheese) =
number of combinations containing Swiss
__________________________________ total number of sandwich combinations
= 6 ___ 12
= 1 __ 2
5 To find the sample space make lists of possible
codes First make a list of codes that start with 0
and have 0 as the second digit
0 0 0 0
0 0 0 1
0 0 1 0
0 0 1 1
List of codes that start with 0 and have 1 as the
second digit
0 1 0 0
0 1 0 1
0 1 1 0
0 1 1 1
List of codes that start with 1 and have 0 as the
second digit
1 0 0 0
1 0 0 1
1 0 1 0
1 0 1 1
List of codes that start with 1 and have 1 as the
second digit
1 1 0 0
1 1 0 1
1 1 1 0
1 1 1 1
In total the number of possible outcomes is 16
There are six codes with exactly two 0s
0 0 1 1
0 1 0 1
0 1 1 0
1 0 0 1
1 0 1 0
1 1 0 0
This means the number of outcomes for a code with
exactly two 0s is 6 Therefore
P(Code exactly two 0s)
= number of favorable outcomes ____________________________ total number of possible outcomes
= 6 ___ 16
= 3 __ 8
Copyright copy by Houghton Mifflin Harcourt 86 All rights reserved
Guided Practice
1
1 2 3 4 5 6
11 sdot 1
= 1
1 sdot 2
= 2
1 sdot 3
= 3
1 sdot 4
= 4
1 sdot 5
= 5
1 sdot 6
= 6
22 sdot 1
= 2
2 sdot 2
= 4
2 sdot 3
= 6
2 sdot 4
= 8
2 sdot 5
= 10
2 sdot 6
= 12
33 sdot 1
= 3
3 sdot 2
= 6
3 sdot 3
= 9
3 sdot 4
= 12
3 sdot 5
= 15
3 sdot 6
= 18
44 sdot 1
= 4
4 sdot 2
= 8
4 sdot 3
= 12
4 sdot 4
= 16
4 sdot 5
= 20
4 sdot 6
= 24
55 sdot 1
= 5
5 sdot 2
= 10
5 sdot 3
= 15
5 sdot 4
= 20
5 sdot 5
= 25
5 sdot 6
= 30
66 sdot 1
= 6
6 sdot 2
= 12
6 sdot 3
= 18
6 sdot 4
= 24
6 sdot 5
= 30
6 sdot 6
= 36
2 There are 15 entries in the table that are multiples
of 4 The total number of entries in the table is 36
P(multiple of 4) = number of multiples of 4
_________________________ total number of entries in table
= 15 ___ 36
3 There are 23 entries in the table that are less than
13 The total number of entries is 36
P(less than 13) = number of entries less than 13 _________________________ total number of entries in table
= 23 ___ 36
4 H
HHH HHT
H
H
Coin 1
List
Coin 2
Coin 3 T
T
HTH HTT
H T
T
H
H T
THH THT
T
H T
TTH TTT
Coin 1
List
Coin 2
Coin 3
5 Count the total number of outcomes in the list 8
6 The only way to get three tails is TTT
7 P = number of outcomes with 3 tails __________________________ total number of outcomes
= 1 __ 8
8 There are 3 way(s) to obtain exactly two heads
HHT HTH THH
P = number of outcomes with exactly 2 heads
__________________________________ total number of possible outcomes
= 3 __ 8
9 You need to know the number of equally likely
outcomes in the sample space
Independent Practice
10
Checkered
Red
Checkered
Red
Blue
Black
Checkered
Red
Checkered
Red
Blue
Black
Checkered
Red
Checkered
Red
Blue
Black
Shirt Pants Shoes
Yellow
Red
Green
11 There are 6 combinations that include red shoes
The total number of combinations is 12 Therefore
P(red shoes) = number of combinations with red shoes ________________________________ total number of combinations
= 6 ___ 12
= 1 __ 2
12 There are four combinations that do not include red
Shirt Pants Shoes
Green Blue Checkered
Green Black Checkered
Yellow Blue Checkered
Yellow Black Checkered
P(no red) = number of outfits with no red _______________________ total number of outfits
= 4 ___ 12
= 1 __ 3
13 Let the other three band members be A B and C
The list of possible combinations is
Rhee Pamela
Rhee A
Rhee B
Rhee C
Pamela A
Pamela B
Pamela C
A B
A C
B C
There is a total of 10 combinations Of these only 1
has Rhee and Pamela so
P(Rhee and Pamela)
= Rhee and Pamela ________________________ total number of combinations
= 1 ___ 10
Copyright copy by Houghton Mifflin Harcourt 87 All rights reserved
14 The sample space can be found from adding all
possible combinations of the two numbers
1 2 3 4 5 6
11 + 1
= 2
1 + 2
= 3
1 + 3
= 4
1 + 4
= 5
1 + 5
= 6
1 + 6
= 7
22 + 1
= 3
2 + 2
= 4
2 + 3
= 5
2 + 4
= 6
2 + 5
= 7
2 + 6
= 8
33 + 1
= 4
3 + 2
= 5
3 + 3
= 6
3 + 4
= 7
3 + 5
= 8
3 + 6
= 9
44 + 1
= 5
4 + 2
= 6
4 + 3
= 7
4 + 4
= 8
4 + 5
= 9
4 + 6
= 10
55 + 1
= 6
5 + 2
= 7
5 + 3
= 8
5 + 4
= 9
5 + 5
= 10
5 + 6
= 11
66 + 1
= 7
6 + 2
= 8
6 + 3
= 9
6 + 4
= 10
6 + 5
= 11
6 + 6
= 12
There is a total of 36 possible sums Of these there
are 10 less than 6
P(sum is less than 6)
= number of sums less than 6 ____________________________ total number of possible outcomes
= 10 ___ 36
= 5 ___ 18
15 The sample space can be found from a tree
diagram
Khakis
Shorts
Shirt Pants Shoes
Collared Jeans
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Khakis
Shorts
T-shirt Jeans
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Sneakers
Flip-flops
Sandals
Total number of possible outcomes is 18 the
number of combinations which include jeans but
not sneakers is 4 Therefore
P(jeans but not sneakers)
= number of outfits with jeans no sneakers
_________________________________ total number of possible outcomes
= 4 ___ 18
= 2 __ 9
16 For each chair lift there are 6 possible trails So you
can multiply the number of choices of chair lifts (3)
by the number of trails (6)
17 Because there are 3 choices for the first item and
2 for the second there are 3 middot 2 = 6 possible
outcomes
18 There is a total of 30 possible shoe sizes Of these
the number of red shoes size 9 or larger is 7
Therefore
P(red and size 9 or larger) =
number of red shoes size 9 or larger
______________________________ total number of possible outcomes
= 7 ___ 30
Focus on Higher Order Thinking
19 Sondra orders one item from each column There
are 4 main dishes 4 vegetables and two sides so
the sample space is 4 sdot 4 sdot 2 = 32 The possible
outcomes of Sondrarsquos order are shown in the tree
diagram
Carrots
Sweet potato
Pasta
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Carrots
Sweet potato
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Carrots
Sweet potato
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Carrots
Sweet potato
Peas
Asparagus
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Tossed saladTomato soup
Salmon
Beef
Pork
Copyright copy by Houghton Mifflin Harcourt 88 All rights reserved
There are 8 total number of outcomes that include
salmon Therefore
Sondra P(salmon) = 8 ___ 32
= 1 __ 4
Gretchen orders a main dish and a vegetable There
are 4 main dishes and 4 vegetables so the sample
space is 4 sdot 4 = 16 The possible outcomes of
Gretchenrsquos order are shown in the tree diagram
Carrots
Sweet potato
PastaPeas
Asparagus
Carrots
Sweet potato
Peas
Asparagus
Carrots
Sweet potato
Peas
Asparagus
Carrots
Sweet potato
Peas
Asparagus
Salmon
Beef
Pork
There are 4 total number of outcomes that include
salmon Therefore
Gretchen (salmon) = 4 ___ 16
= 1 __ 4
Because the probabilities for Sondra and Gretchen
are equal neither has a greater probability of getting
a meal that includes salmon
20 a For possible two-digit codes consider first codes
that begin with 1 12 13 14 15 There are a total
of 4 possible codes This pattern continues for
each of the 5 digits and therefore we have a total
of 4 + 4 + 4 + 4 + 4 = 20 possible two-digit
codes (four codes each that begin with each of
the numbers 1ndash5)
For possible three-digit codes there are 12
possible codes that begin with 1 and so there are
12 possible codes for each of the numbers 1ndash5
making a total of 5 sdot 12 = 60 possible three-digit
codes
We can predict the number of possible five-digit
codes because we know there are 60 possible
three-digit codes and for each of these there are
only two digits that can be added to the end of
each code to make them five-digit codes These
are the digits that were not used in the three-digit
code and they have two possible orders for a
total of 60 sdot 2 = 120 possible five-digit codes
As a concrete example again consider the three-
digit codes that begin with 1 Tacking on the digits
which are not included in these three-digit codes
in both orders we have 12345 12354 12435
12453 12534 12543 13245 13254 13425
13452 13524 13542 14235 14253 14325
14352 14523 14532 15234 15243 15324
15342 15423 15432 If we do the same for the
three-digit codes beginning with 2ndash5 we will find
the 120 possible five-digit codes
b Now that the numbers can repeat for two-digit
codes take the 20 codes from before and add five
more codes (11 22 33 44 55) which makes a
total of 25 two-digit codes
For three-digit codes take the 60 codes from
before and add the 5 codes that have all digits
the same plus codes which have two digits
which are repeats To find these consider first the
codes with the first two digits the same 112 113
114 115 221 223 224 225 331 332 334 335
441 442 443 445 551 552 553 554 There
are 20 possible codes There are also 20 possible
codes with the last two digits the same Finally
consider the codes where the first and last digits
are the same For the repeated digit 1 we have
121 131 141 151 or 4 possible codes For each
of the digits 1ndash5 we have 4 possible codes for a
total of 4 sdot 5 = 20 Therefore the overall total
60 + 5 + 20 + 20 + 2 = 125 three-digit codes
To solve for how many possible 5 digit codes
there are notice a pattern in the codes For
two-digit codes the total possible codes is the
number of possible digits raised to the power
equal to the number of digits in the code or
52 = 25 For three-digit codes the number of
possible digits is the same and the number
of digits in the code is 3 so we have 53 = 125
Following this pattern there are 55 = 3125
possible five-digit codes
c Sample answer The better choice is to have the
digits repeat there are more unique codes with
repeated digits than without so it would be more
difficult for someone to guess a code for a locker
LESSON 133
Your Turn
1 There are 4 numbers less than 5 on a standard
number cube There are 6 possible outcomes so
P(number less than 5) = 4 __ 6 = 2 __
3
The number of events is 250 Therefore
P(number less than 5) times Number of events =
2 __ 3 times 250 = 16666 or about 167 times
Copyright copy by Houghton Mifflin Harcourt 89 All rights reserved
2 Set up a proportion The probability of getting
heads is 1 __ 2
1 __ 2 = x ___
18
1 __ 2 = x ___
18
x = 9
about 9 times
3 There are 17 total marbles and 8 are red Therefore
P(red) = 8 ___ 17
P(not red) = 1 - 8 ___ 17
= 9 ___ 17
It is more likely that he picks a marble that is not red
4 No Sample answer There is a total of 71 bills in the
bag and there are 11 bills worth $6 or more
Therefore
P(bill worth $6 or more) = 11 ___ 71
This is about a 15 probability so it is not likely you
will win enough to pay for your ticket
Guided Practice
1 An equally likely chance means that the probabilities
of being assigned to each crew are the same and
since there are three possibilities each has a
probability of 1 __ 3
Apartment 1 __ 3 Condo 1 __
3 House 1 __
3
The probability of being assigned to house crew is 1 __ 3
Set up and solve a proportion
1 __ 3 = x ___
18
1 __ 3 = x ___
18
x = 6
This means that Bob can expect to be assigned to
the house crew about 6 times out of 18
2 Since half of the ticket holders will receive a prize
this means that 300 divide 2 = 150 people will receive a
prize Because they are equally likely to receive one
of three prizes the probability of winning each of the
prizes is 1 __ 3 so the probability of winning a movie
ticket is 1 __ 3 The number of events is 150 Therefore
P(movie ticket) times Number of events = 1 __ 3 times 150 =
50 or 50 people are predicted to win a movie ticket
3 The total number of students in Mr Jawaranirsquos class
is 28 The probabilities of picking a student at
random with a certain eye color are
P(hazel) = 9 ___ 28
P(brown) = 10 ___ 28
P(blue) = 7 ___ 28
P(green) = 2 ___ 28
The event with the greatest probability is choosing a
person with brown eyes
4 You can find and compare probabilities Or you can
use probability to set up and solve a proportion or
an equation that relates the probability to the
unknown quantity
Independent Practice
5 The total number of marbles in the bag is 9 The
number of white or gray marbles is 3 Therefore
P(white or gray) = 3 __ 9 = 1 __
3
The number of events is 45 The equation to make a
prediction is then
P(white or gray) times Number of events = 1 __ 3 times 45 = 15
You can expect to get 15 white or gray marbles
6 A spinner which has an equal likelihood to land on
green or yellow means that the number of green and
yellow sections must be equal More likely to land on
red means that there must be more red sections
than yellow or green A Sample answer is
Y GRR
R R
RR
7 Because half the deck is red the probability of
drawing a red card is 1 __ 2 Because there are three
face cards for each of four suits there are 3 sdot 4 = 12
face cards and the probability of drawing a face
card is 12 ___ 52
To compare 1 __ 2 and 12 ___
52 use the least
common denominator of 52 so that 1 __ 2 = 26 ___
52 Given
that 12 ___ 52
lt 26 ___ 52
the probability of drawing a red card
is higher than of drawing a face card and it is more
likely that Dawn draws 2 red cards
8 The total number of aces in a deck is 4 Therefore
P(ace) = 4 ___ 52
= 1 ___ 13
The number of events is 39 The equation to make a
prediction is then
P(ace) middot Number of events = 1 ___ 13
times 39 = 3
He is predicted to draw an ace 3 times
9 The total number of red cards is 26 Therefore
P(red card) = 26 ___ 52
= 1 __ 2
The number of events is 1000 The equation to
make a prediction is then
P(red card) sdot Number of events = 1 __ 2 sdot 1000 = 500
The player is predicted to turn over a red card as the
first card 500 times
10 The sample space can be found from adding all
possible combinations of the two numbers
times6
times6
times9
times9
Copyright copy by Houghton Mifflin Harcourt 90 All rights reserved
1 2 3 4 5 6
1 2 3 4 5 6 7
2 3 4 5 6 7 8
3 4 5 6 7 8 9
4 5 6 7 8 9 10
5 6 7 8 9 10 11
6 7 8 9 10 11 12
There is a total of 36 possible sums Of these there
are 5 ways to roll a sum of 8 and 2 ways to roll a
sum of 11 The probabilities are
P(sum of 8) = 5 ___ 36
P(sum of 11) = 2 ___ 36
Because the probability of rolling a sum of 8 is
greater than that of rolling a sum of 11 ( 5 ___ 36
gt 2 ___ 36
) John is more likely to win
11 There are 5 possible numbers greater than 15 so
P(greater than 15) = 5 ___ 20
= 1 __ 4
The number of events is 180 The equation to make
a prediction is then
P(greater than 15) times Number of events =
1 __ 4 times 180 = 45
The chosen number will be greater than 15 for 45
days in the school year
12 The sample space for a standard cube is 36 and
there are 3 combinations that will have a sum of 4
so P(sum of 3) = 3 ___ 36
= 1 ___ 12
The number of events is 36 The equation to make a
prediction is then
P(sum of 3) times Number of events = 1 ___ 12
middot 36 = 3
Eben is predicted to roll a sum of 4 a total of 3 times
13 Sample answer No Every time you flip a coin the
probability of heads is 1 __ 2 but in reality you could flip
a coin many times and have it land heads up every
time
14 Sample answer A bag of marbles contains red and
blue marbles that are different sizes Since it is easy
to feel the difference between the two colors all of
the outcomes are not equally likely You cannot make
a prediction using theoretical probability
Focus on Higher Order Thinking
15 Sample answer What is the theoretical probability
that the coin lands on heads and you pick a marble
that is not green
The probability that the coin lands on heads is 1 __ 2
and the probability that the picked marble is not
green is 3 + 9 _________
3 + 8 + 9 = 12 ___
20 The product of these two
probabilities is 1 __ 2 times 12 ___
20 = 12 ___
40
16 Sample answer It is much more likely that he rolls a
5 or the coin lands on heads
The probability that Horace rolls a 5 and the coin
lands on heads is given by
P(5 and heads) = 1 __ 2 times 1 __
6 = 1 ___
12
In the case where Horace rolls a 5 or the coin lands
on heads the probability is given by
P(5 or heads) = 1 __ 6 + 1 __
2 - 1 __
6 times 1 __
2 = 7 ___
12
17 Yes but only theoretically because in reality nothing
can occur 05 times Sample answer The probability
that a flipped coin lands heads up is 1 __ 2 so in 75 flips
you can expect heads about 75 ___ 2 or 375 times
LESSON 134
Your Turn
1 Sample answer (data and percent will vary)
Trial Numbers generated 3 Males first
1 0 0 1 No
2 0 1 No
3 1 No
4 0 1 No
5 1 No
6 0 0 0 1 Yes
7 0 0 1 No
8 0 1 No
9 1 No
10 0 0 0 0 1 Yes
For these data the experimental probability that the
elephant gives birth to 3 male calves before having a
female calf is 2 ___ 10
or 20
2 Sample Answer (data and percent will vary)
Trial Numbers generated Correct answers
1 1 0 1 1 0 3
2 0 1 0 0 1 2
3 0 0 0 0 1 1
4 0 0 1 1 0 2
5 1 1 1 1 1 5
6 1 0 0 0 0 1
7 1 0 1 1 0 3
8 1 0 1 0 0 2
9 0 1 1 1 1 4
10 0 0 0 0 0 0
The experimental probability that he gets at least 2
questions right is 7 ___ 10
= 70
Copyright copy by Houghton Mifflin Harcourt 91 All rights reserved
Guided Practice
1 Since there is a 30 or 3 ___ 10
chance of drought let
the numbers 1 to 3 represent years with a drought
and the numbers 4 to 10 represent years without
a drought Since we are interested in the next 4
years perform multiple trials generating 4 random
numbers each time
2
Trial Numbers generated Drought years
1 10 3 5 1 2
2 10 4 6 5 0
3 3 2 10 3 3
4 2 10 4 4 1
5 7 3 6 3 2
6 8 4 8 5 0
7 6 2 2 8 2
8 6 5 2 4 1
9 2 2 3 2 4
10 6 3 1 5 2
3 In 8 out of the 10 trials there was a drought in at
least one of the years The experimental probability
of a drought in at least 1 of the next 4 years is
8 ___ 10
= 80
4 Sample answer Generate whole numbers from
1 to 4 Let 1 to 3 represent the event occurring
and 4 represent the event not occurring
Independent Practice
5 There is only 1 trial Trial 6 where it took exactly
4 contestants to get a winner
6 Since 1 out of 10 trials resulted in exactly
4 contestants the probability is 1 ___ 10
= 10
7 The trials for which at least 4 hurricanes struck are
Trials 2 and 7 or 2 out of 10 trials Therefore the
probability is 2 ___ 10
= 20
8 It is fewer than expected based on the simulation
9 It is unlikely but it is not impossible Each of the 3
numbers could be any number from 1 to 10
However there are 10 possible first numbers 10
possible second numbers and 10 possible third
numbers or a total of 1000 possible numbers when
generating three numbers from 1 to 10 The
probability of generating three 10s is 1 _____ 1000
10 Sample answer Use the numbers 1ndash5 where 1 2
and 3 represent packs which contain a player from
Erikarsquos favorite team Generate numbers randomly
and stop when you get a 1 2 or 3
Trial Numbers generated Number of Packs
1 3 1
2 4 2 2
3 2 1
4 1 1
5 2 1
6 4 5 3 2
7 4 2 2
8 4 5 2 1
9 4 4 3 3
10 5 1 2
The average number of packs she needs to buy is
1 + 2 + 1 + 1 + 1 + 2 + 2 + 1 + 3 + 2
_________________________________ 10
= 16 ___ 10
= 1 3 __ 5
packs Since she cannot buy a fraction of a pack
she must buy 2 packs
Focus on Higher Order Thinking
11 Sample answer The probability that she makes a
shot is 375 = 3 __ 8 Use the whole numbers from 1 to
8 with 1ndash3 representing shots she makes and 4ndash8
representing shots she misses For each new trial
generate 10 random numbers Count the number
of times 1 2 or 3 appears in each trial Divide the
number of trials in which she made at least 3 shots
by the total number of trials
12 Sample answer Their simulation was not
appropriate perhaps because they chose an
incorrect model You would expect there to have
been exactly 4 heads on more of the trials and
more variation in the number of heads in general
MODULE 13
Ready to Go On
1 P(red) = number of red marbles ___________________ total number of marbles
= 12 ___________________ 12 + 12 + 15 + 9 + 12
= 12 ___ 60
= 1 __ 5 020 or 20
2 P(diamond or spade)
= number of diamonds and spades
___________________________ total number of cards
= 13 + 13
_______ 52
= 26 ___ 52
= 1 __ 2 050 or 50
3 The most likely color of marble chosen is the most
common color in this case green
Copyright copy by Houghton Mifflin Harcourt 92 All rights reserved
4 In order to find the experimental probability count
the number of trials in which 1 occurs at least once
In this case there are 4 trials that generated a 1
Therefore the experimental probability is 4 ___ 10
or
40
5 Sample answer You can find the theoretical
probability of an event and then use it to make a
prediction by setting up a proportion
Copyright copy by Houghton Mifflin Harcourt 93 All rights reserved