How do I find the following probabilities?

P(A|A ∪ B)

P(A|A ∩ B)

P(A ∩ B|A ∪ B)

?2019-01-26T08:53:53Z

P(A/AB) = P(A (AB)) / P(AB)

P(A/AB) = P(A(AB)) / P(AB)

P(AB/AB) = P(AB)  (AB) / P(AB).

Dixon2019-01-25T19:12:19Z

P(Q I S) means reduce your world down to just S. What fraction of it is Q?
And it is Q/S

P(A|A ∪ B) = A/(A ∪ B)

P(A|A ∩ B)
Even in words the probability of A given the intersection of A and B is clearly 1.

P(A ∩ B|A ∪ B) = (A ∩ B)/(A ∪ B)