Question

can some one check my answer please!
Determine whether each situation involves a permutation or a combination.Then find the number of possibilities.
selecting nine books to check out of the library from a reading list of twelve
9!
permutation

Answer 1

combination, you are picking a group of 9 books out of 12, order does not matter.

Answer 2

\[\frac{12!}{3!9!} = \frac{12*11*10}{3*2*1} = 2*11*10 = 220\]