Question

Let A and B be two events. If P (A) = 0.2, P (B) = 0.4, P (A∪B) = 0.6, then P (A | B) is equal to

(A) 0.8

(B) 0.5

(C) 0.3

(D) 0

Answer 1

The correct answer is (D). From the given data P (A) + P (B) = P (A∪B).

This shows that P (A∩B) = 0. Thus P (A | B) = P(A∩B)/P(B) = 0