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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 10 Page 704

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

210

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=7 and r=3. Let's substitute these values into the formula.

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

n= 7, r= 3

_7 P_3 = 7!/( 7- 3)!

Subtract term

_7 P_3 = 7!/4!

Write as a product

_7 P_3 = 7* 6* 5* 4!/4!

a/b=.a /4!./.b /4!.

_7 P_3 = 7* 6* 5/1

a/1=a

_7 P_3 = 7* 6* 5

Multiply

_7 P_5 = 210

Subchapter links

Communicate Your Answer p.699

Monitoring Progress p.700-703

Exercises p.704-706