# Detecting a fair coin

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• February 19th 2013, 07:17 PM
broccoli7
Detecting a fair coin
There are three coins, one of them is fair, while the other two are biased with probabilities of heads being 14 and 34 respectively. A coin is chosen at random. How many tosses are needed to have a greater than 50% probability that it is fair.

Spoiler: Probability Puzzles: Choosing the Fair Coin