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 = [tex]\frac{n!}{r!(n-r)!}[/tex]
27C4 = [tex]\frac{27!}{4!(27-4)!}[/tex] = [tex]\frac{27!}{4!(23!)!}[/tex]= 17550
The manager can choose a group of 4 for a prize in 17,550 ways.
