A video store has 27 new release movie posters.
the manager choose a group of 4 for a prize.
When we choose a group of 4, the order does not matters.
So we use combination
We need to find 4 from 27 new release movie posters.
27C4
nCr =

27C4 =
=
= 17550
The manager can choose a group of 4 for a prize in 17,550 ways.