+129899 a) C (5,3) = 10 subsets
b)
Total of subsets with no elements = 1
Total of subsets with one element = 5
Total of subsets with two elements =C (5,2) = 10
Total of subsets with three elements = C(5,3) = 10
So....we have 1 + 5 + 10 + 10 = 26 subsets with no more than three elements
