1. The problem statement, all variables and given/known data Given N identical objects and N additional objects that are different from these and from each other, find the number of ways to select n objects out of these 2N objects. 2. Relevant equations Either P(n,k) or C(n,k) or n^k or maybe even (n+k+1)/k 3. The attempt at a solution Looking at these...so half the set is identical and the other half is distinct from the first half and from them selves. So I will call the first set S and the second set T to help me keep them apart. So for the first set everything is identical and w can select up to N of them... my notes seem to indicate i would go about it as (S+N+1)/N and then the second set they are distinct from each other and we can select N of them, so T^N? Are those two formulas in the right direction? If so would I multiply those together to get the correct answer?