# Conditional Probability: Fair and unfair coin?

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A box contains 5 fair coins and 5 biased coins. Each biased coin has a probability of a head 4/5. A coin is drawn at random from the box and tossed. Then a second coin is drawn at random from the box (without replacing the first one.)

Given that the first coin has shown head, What is the probability of second coin is fair?

posted Jul 20, 2017
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