Originally Posted by

**kittysnyde** I am unsure about the following problems, I put what I think the answer is, would appreciate any help. Thanks!

1. For two events A and B, suppose P(A)= .45, P(B)=.75 and P(BlA)= .45

Are A and B independent?

I said no. For them to be independent, P(BlA) would have to equal .75

2. The events A and B are mutually exclusive. If P(A)= .4 and P(B)=.5 what is P(A and B)?

I feel like this might be a trick question? I thought mutually exclusive refered to P(A or B). If it means the same as independent then I answered

P(A and B)=P(A)*P(B)

3. Given P(A and B)= .25, P(A)= .20 and P(A and B)= .30 find P(B)

Just rearranging I got:

P(A or B)= P(A) + P(B) - P(A and B)

P(B) = P(A or B) - P(A) + P(A and B)