Question

If P(A) = 1/2, P(B) = 0, then P(A Î B) is???

Answer 1

It is given that P(A) = 1/2 and P(B) = 0
P(A Î B) = P (A ∩ B) / P(B) = P (A ∩ B)/0

As zero is in the denominator, the expression can't be defined. 

In short, final answer is not defined.

Hope it helped.