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Big Ideas Math Geometry, 2014

BI

Big Ideas Math Geometry, 2014 View details

5. Permutations and Combinations

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Exercise 9 Page 704

Recall the formula for a permutation, _n P_r = n!/(n-r)!.

20

Practice makes perfect

To evaluate the given permutation, we will use the corresponding formula. _n P_r = n!/(n-r)! We are given that n=5 and r=2. Let's substitute these values into the formula.

_n P_r = n!/(n-r)!

n= 5, r= 2

_5 P_2 = 5!/( 5- 2)!

Subtract term

_5 P_2 = 5!/3!

Write as a product

_5 P_2 = 5* 4* 3!/3!

a/b=.a /3!./.b /3!.

_5 P_2 = 5* 4/1

a/1=a

_5 P_2 = 5* 4

Multiply

_5 P_2 = 20

Subchapter links

Communicate Your Answer p.699

Monitoring Progress p.700-703

Exercises p.704-706