problems in linear equations

St. Angela ( Group 5)

PROBLEMS IN LINEAR

EQUATIONS

1ST PROBLEM

Paula is now 18 years old and her colleague Monica is now 14 years old. How many years ago was Paula twice as old as Monica?

1ST PROBLEM

Past Present

Paula 18-x 18

Monica 14-x 14

CHART

(18-x) - 2(14-x)18-x = 28-2x

SOLUTION

X = 10

ANSWER

2nd Problem

A triangular Pyramid with a square base has a height equal to two times the side of it’s base. Find the dimension of the Pyramid if the volume is 100 cu. cm

2ND PROBLEM

Height = 2

Side of the base = x

NOTE = Volume of the pyramid = 1/3 ( Area of the base) x height

100 = 1/3 (x^2)(2x)

100 = 2/3 (x^3)

X = cube root of 150

Height = 2x

2( cube root of 150)

SOLUTION

Height = 2 cube root of 150

Side of base = cube root of 150

ANSWER

3RD PROBLEM

JJ is three times older as Jan-Jan. Three years ago, JJ was four times as old as

Jan-Jan. the sum of there age is?

3RD PROBLEM

Past Present

JJ 3x-3 3x

Jan-Jan X-3 x

CHART

3x-3 = 4(x-3)3x-3 = 4x-12

X-12 = 3x = Jan- Jan’s age3x = 27 ( JJ’s age )

SOLUTION

Sum of ages = 9 + 27 = 36

ANSWERS