UPSC NDA Math Model Paper 4

Given, A and B are two events of a sample space S such that P(A) = 0.2, P(B) = 0.6 and P(A|B) = 0.5
To find: P(A'|B)
By complementary rule of Conditional probability,
P(A'|B) = 1 - P(A|B)
⇒P(A'|B) = 1 - 0.5
⇒P(A'|B) = 0.5
Hence, If A and B are two events of a sample space S such that P(A) = 0.2, P(B) = 0.6 and P(A|B) = 0.5 P(A'|B) = 0.5