# Math Help - Mutually exclusive?

1. ## Mutually exclusive?

P(A)- 1/2
P(A|B)- 1/3
P(B|A) - 1/2

I don't think they are independant considering event B changes the probablity of event A occuring. what I can't figure out is P(B) or P(A or B), last P(A and B). Any input is appreciated.

I think the P(A and B) is (1/2)(1/2)= 1/4, if you could tell me if thats wrong why you would make my day.

2. Originally Posted by GideonSD
P(A)- 1/2
P(A|B)- 1/3
P(B|A) - 1/2

I don't think they are independant considering event B changes the probablity of event A occuring. what I can't figure out is P(B) or P(A or B), last P(A and B). Any input is appreciated.
$P(B|A)=\frac{P(A\cap B)}{P(A)}$ implies that $P(A\cap B)=\frac{1}{4}$.

Moreover, $P(B)=\frac{P(A\cap B)}{P(A|B)}$