Question

The probability that A speaks truth is 4/5 while this probability for B is 3/4. The probability that they contradict each other when asked to speak on a fact, is

(a) 3/20

(b) 1/5

(c) 7/20

(d) 4/5

Answer 1

The correct option is (c) 7/20.

Explanation:

Given, probabilities of speaking truth are

P(A) = 4/5 and P(B) = 3/4

And their corresponding probabilities of not speaking truth are

P bar(A) = 1/5

P bar (B) = 1/4

The probability that they contradict each other