Question: The U.S. Senate consists of 100 senators, with 2 from each of the 50 states. There are d Democrats in the Senate. A committee of size c is formed, by picking a random set of senators such that all sets of size c are equally likely.
(a) Find the expected number of Democrats on the committee.
(b) Find the expected number of states represented on the committee (by at least one senator).
(c) Find the expected number of states such that both of the state's senators are on the committee.