A speaks the truth 5 out of 7 times and B speaks truth 8 out of 9 times. What is the
probability that they contradict each other in stating the same fact?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is Option 4 i.e. 1/3
The probability that A speaks the truth is 5/7
The probability that A does not speak the truth = 2/7
The probability that B speaks the truth is 8/9
The probability that B does not speak the truth = 1/9
According to the question
They contradict each other in stating the same fact
then the probability = 5/7 * 1/9 + 2/7 * 8/9
= 5/63 + 16/63 = 21/63 = 1/3