jmc

Choosing a committee is a combination, since the order does not matter. We are choosing a 4-person committee from 25 people, so there are 25 ways to pick the first person, 24 ways to pick the second person, etc. However, we must divide by $4!$ since order doesn't matter. So the answer is $\frac{25\times 24\times 23\times 22}{4!}=\boxed{12,650}$.