There are 100 members in the U.s. Senate(2 from each state)In how many ways can a committee of 5 senators be formed if no state may be represened more than once.
I think that this a permutation problem but when i re-read it it might be a combination problem
Senators a and b are from state "whocares"
Senators x and y are from state "Ido"
the combinations with half the senators are:
Multiply that by 2 and you get 2 different combinations, and yet possible combinations are:
it's an unfortunate trick of the problem