how many different ways can you pick 2 objects from a set of 7 objects?
The number of ways to pick m objects from n is
C(n,m) = n!/(m!(n-m)!)
So 2 objects from 7 there are C(n,m) [n choose m] ways.
C(n,m)=7!/(5!(7-5)!)=28
C(n,m) = n!/(m!(n-m)!)
So 2 objects from 7 there are C(n,m) [n choose m] ways.
C(n,m)=7!/(5!(7-5)!)=28