Question

Which of the following expressions would give the number of ways to choose a group of 7 from a group

of 15?
151!/7!8!
7!/15!8!
7!15!7!

Answer 1

• A) 15!/(7!8!)

Explanation:

We are looking for the combination of 7 out of 15.

This is written as

• 15C7

This is calculated as

• 15!/(7!(15-7)! = 15!/(7!8!)

Correct choice is A