if you have 6 books how many groups of four different books can you make out of the six?
If we assume that the order we choose those four books doesn't matter then it is
nCr=
6!/(2!4!)
= ?
Isn't it 6*6*6*6???
If we assume that the order we choose those four books doesn't matter then it is
nCr=
6!/(2!4!)
= ?
Isn't it 6*6*6*6???