I have a simple question for you guys but I am studying for exams and I honestly forgot how this was done.

Here is the problem:

"A vase contains 4 white marbles, 3 red and 2 green. You draw marbles 2 without putting the first one back after the second.

What are the chances that you draw a red marble after the first one was green? What are the chances that you draw 2 white marbles? What are the chances that you draw a white and a red marble?"

I see I gotta calculate P(A ∩ B) / P(B) but how do I calculate P(A ∩ B) then?