Question

If A and B are two events associated with a random experiment for which P(A) = 0.60, P(A or B) = 0.85 and P(A and B) = 0.42, find P(B).

Answer 1

Given: P(A) = 0.60, P(A or B) = 0.85 and P(A and B) = 0.42

We know that, P(A or B) = P(A) + P(B) – P(A and B)

By substituting values in the above formula, we get

0.85 = 0.60 + P(B) – 0.42

0.85 = 0.18 + P(B)

0.85 – 0.18 = P(B)

0.67 = P(B)

or P(B) = 0.67