A person speaks truth 3 out of 4 times. A fair 6-sided die is thrown and the person reports that it is a 6. What is the probability that it was actually a 6?
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We just need to justify the person is telling truth or not, and P r ( this person tells truth ) = 4 3
Some may use below table to find out the solution:
They suggest the prob. = 2 4 3 + 2 4 5 2 4 3 = 8 3
But for the case the person tell lies when the die is NOT rolled 6, there is only 5 1 chance that the person reports the rolled number is 6
So the prob. should be = 2 4 3 + 2 4 5 5 1 2 4 3 = 4 3