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A man speaks the truth 8 out of 10 times. A die is tossed. He reports that it was 5. What is the probability that it was actually 5?

Solution

✅ Correct Option: 2

By Bayes' theorem, the numerator is 16×45=430\frac{1}{6}\times\frac{4}{5} = \frac{4}{30} and the false-report term is 56×15=530\frac{5}{6}\times\frac{1}{5} = \frac{5}{30}. So the probability is 4/309/30=49\frac{4/30}{9/30} = \frac{4}{9}.

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