Suppose that A and B are events defined on a common sample s

Suppose that A and B are events defined on a common sample space and that the following probabilities are known. Find P(A or B). (Give your answer correct to two decimal places.)

P(A) = 0.26, P(B) = 0.36, P(A | B) = 0.22

Solution

Given, P(A) = 0.26; P(B) = 0.36; P(A|B) =0.22

P(A|B) = P(A and B) /P(B) = P(A and B) /0.36 = 0.22

P(A and B) = 0.22 * 0.36 =0.0792

P(A or B) = P(A) + P(B) -P(A and B)

= 0.26 + 0.36 - 0.0792 = 0.5408