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You are lost in the national park of Kabrastan. The park population consists of tourists and kabrastanis. Tourists comprise $2/3$ of the population the park, and give a correct answer to requests for directions with probability $3/4$.

The air of Kabrastan has an amnesaic quality however, and so the answers to repeated questions to tourists are independent, even if the question and the person are the same.

If you ask a Kabrastani for directions, the answer is always wrong.

Suppose you ask a randomly chosen passer-by whether the exit from the park is East or West. Theanswer is East. You then ask the same person again, and the reply is again East.

What is the probability of East being correct?

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We have to make a few additional unlikely assumptions, such as that we have chosen "at random" a Kabrastani park, and that half of them have an East exit only, and half have a West exit only. –  André Nicolas Sep 5 '13 at 9:23
    
Would I get a credit for solving this for you? –  Sasha Sep 5 '13 at 13:29

1 Answer 1

prob that the answer is east =(1/2)(2/3)(3/4)(3/4)/((1/2)(2/3)(3/4)(3/4)+(1/2)(2/3)(1/4)(1/4)+(1/2)(1/3)(1)(1))=1/2....HOPE THIS HELPS...

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You may want to improve the formatting of this, as well as adding some explanation to your reasoning. –  mrf Sep 12 '13 at 11:40

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