1. 12.2 Find Probability Using Permutations
Mrs. vazquez
Geometry

2. (S.cp.)1 & 9, (s.md)6 & 7 Essential Question:
How are many different arrangements can there be?
Objective:
Students will be able to use the formula for the number of permutations.

3. permutations definition:
an arrangement of objects in which order is important
factorial: (!) evaluated by multiplying the integers in descending order
5! = 5∙4∙3∙2∙1 = 120

4. permutations formulas
nPn = n!
the # of permutations of n objects
Ex: 4P4 = 4! = 24
nPr =
the # of permutations of n objects taken r at a time
Ex: 4P2 =
= = 12

5. solve Your band writes 15 songs. You will record 9 of them for a CD.
How many different ways can you order the songs on the CD?

6. solve
For a parade, you will ride on a float with your soccer team. There are 14 floats and their order is chosen at random. Find the probability that the team is first & the chorus is second.