im sure this will be easy for most, i just am having trouble knowing where to start as im new to probability. the question is as follows:

"A science committee of 3 people is to be formed from a group of 17 scientists (7 biologists, 4

physicists and 6 chemists) with each possible committee equally likely.

What is the probability the committee vote in favour of a proposal given:

(a) all biologists in favour, everybody else against?

(b) all chemists against, everybody else in favour?

(c) all biologists in favour, all chemists against and all physicists abstain?"

thanks