Thread: Combination problesm

Been stuck on this question for a while i think it uses combinations, i could be mistaken, any help or solutions would be appreciated. well anyways:
A class coinsists of 8 girls and 6 boys. Acomitee is to be formed coinsisting of 4 girls and 2 boys. In how many ways can a teracher choose the comitee if:
A.) Freddie the principals son has to be on the commitee? (Answer 350)
B.) The twins Jack and Jill are both on the comitee?(350)
C.)The twins Jack and Jill cannot be on the comitee? (875)

A.) Freddie the principals son has to be on the commitee? (Answer 350)
Hmmm, (8C4)(5C1)?
Since his son, a boy has to be on it, then that mean you only need to choose one more boy out of the 5 left over?


B.) The twins Jack and Jill are both on the comitee?(350)
(7C3)(5C1)(2C1)? I am not sure though.
(2C1) because If one of the twin get selected, then the other one is in too?


C.)The twins Jack and Jill cannot be on the comitee? (875)
(8C4)(6C2) - (7C3)(5C1)
1050 - 175 = 875.