Probability Question - Prove Formula

1. Feb 4, 2013

GreenPrint

1. The problem statement, all variables and given/known data

Hi,

Prove P(AUB|C) = P(A|C)+P(B|C)-P(A∩B|C)

2. Relevant equations

3. The attempt at a solution

I start off from here

$P(AUB|C)=\frac{P(AUB)P(C|AUB)}{P(C)}$

I don't know where to go from here. Thanks for any help that you can provide.

2. Feb 4, 2013

GreenPrint

I think I actually figured this one. I realize that A, B, C may not necessairly be independent and for whatever reason I thought they where so I wasn't getting the correct answer