3.4 counting principles i.the fundamental counting principle: if one event can occur m ways and a...
TRANSCRIPT
3.4 Counting Principles
I. The Fundamental Counting Principle: if one event can occur m ways and a second event can occur n ways, the number of ways the 2 events can occur in sequence is m x n.
Page 150-151 Examples 1 & 2
II. Permutations
• An ordered arrangement of objects• The number of different permutations of n
distinct objects is n!• Factorial: n! = n(n-1)(n-2)…• P152 Example 3
•nPr = n! The number of permutations of n
(n-r)! distinct objects taken r at a time
• P152-153 Examples 4 & 5
• Distinguishable Permutations:
• P154 Example 6 and TIY6
III. Combinations
• A selection of r objects from a group of n objects without regard to order
• nCr = n!
(n-r)!r!
• P155 Example 7 and TIY#7
IV. Applications of Counting Principles1. A word consists of 1 M, 4 Is, 4 Ss, and 2
Ps. If the letters are randomly arranged in order, what is the probability the arrangement spells the word Mississippi?
2. A word consists of 1 L, 2 Es, 2 Ts, and 1 R. If the letters are randomly arranged in order, what is the probability the arrangement spells the word Letter?
3. Find the probability of being dealt five diamonds from a standard deck of playing cards. (In poker, this is a diamond flush.)
4. A jury consists of 5 men and 7 women. Three are selected at random for an interview. Find the probability that all three are men.
• P158 #24-38even