A couple has three babies.

a. what are the chances 3 are girls?

b. what are the chances there will be boy,girl,boy?

http://i49.tinypic.com/2isyo0.jpg
^ is tree diagram

a.

n(S)=(2^3) = 8

n(A)=7?

P(A)=7/8

b. n(S)=(2^3)=8

n(A)=3

P(A)=3/8

Also.. another from the textbook:

Suppose your school's basketball team is playing a four-game series against another school. So far this season, each team has won three of the six games in which they faced each other.

a) Determine the probability of your school winning exactly two games. (use your tree diagram)

I'm not sure how to do this.

n(S)=(2^4)=16

n(A) = ?

P(A) = n(A)/16

How to find n(A) here i'm not sure