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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 16 Page 704

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

6 375 600

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=25 and r=5. Let's substitute these values into the formula.

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

n= 25, r= 5

_(25) P_5 = 25!/( 25- 5)!

Subtract term

_(25) P_5 = 25!/20!

Write as a product

_(25) P_5 = 25* 24* 23* 22* 21* 20!/20!

a/b=.a /20!./.b /20!.

_(25) P_5 = 25* 24* 23* 22* 21/1

a/1=a

_(25) P_5 = 25* 24* 23* 22* 21

Multiply

_(25) P_5 = 6 375 600

Subchapter links

Communicate Your Answer p.699

Monitoring Progress p.700-703

Exercises p.704-706