I think I'm beginning to understand this, so I would appreciate if someone could critique the following:

4. A group consists of 12 men and 8 women. How many ways are there to ...

4.a) form a committee of size 5?

4.b) form a committee of size 5 containing two men and three women?

4.c) form a committee of size 6 containing at least three women?

First approach:

Second approach: