Counting Using Recursion
Choosing K out of N items. Need to write in terms of choosing from N-1 items;
Choose 1 and then choose K-1 from rest (N-1) + Eliminate 1 and choose K from N-1 items.
= C(N-1,K-1) + C(N-1,K) if 0 < K < N
Try it with a real-life example, say , marbles.
Reading Assignment: Mad Scientist Problem(79-81)