Question

    A speaks the truth 5 out of 7 times and B speaks truth 5 out of 9 times. What is the probability that they contradict each other in stating the same fact?

    A 10/21 Correct Answer Incorrect Answer
    B 7/15 Correct Answer Incorrect Answer
    C 9/20 Correct Answer Incorrect Answer
    D 5/21 Correct Answer Incorrect Answer

    Solution

    P (A truth) = Probability that A speaks the truth =5/7 P (A lie) = Probability that A lies = 1 - P (A truth) =1-5/7 =2/7 P (B Truth) = Probability that B speaks the truth = 5/9 P (B lie) = Probability that B lies = 1- P (B truth) = 1-5/9 =4/9.

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