+0 how many non-empty subsets of {1,2,3,4,5} contain an element whose value is the number of elements in the subset?
+129830 There are 2^5 - 1 = 31 non-empty subsets of the given one
Any subset containing "5" is what we are looking for
The number of non-empty subsets NOT CONTAINING "5" = the number of non-empty subsets of {1,2,3,4} = 2^4 -1 = 15
So....the number including "5" = 31 - 15 = 16
