Eric has 5 cds that he is going to give away. he lets his best friend choose 3 of the 5 cds. how many different groups of 3 cds are possible?

Given a group of n object. We want to make a selection of k objects out of the n object. This can be done in 

C(n, k) many ways, where ,

where k!=1*2*3*...(k-1)*k

Thus, we can do the selection of 3 cd's out of 5, in C(5,3) many ways, 

where 



10

It took off from 11 degrees