# Clue to Puzzle #57: Making a Fair Decision With a Biased Coin

57. How can you use a biased coin to make an unbiased decision?

That is to say the coin does not give heads or tales with equal probability. How can you ensure that decisions made with the coin do have a 50:50 chance?

That is to say the coin does not give heads or tales with equal probability. How can you ensure that decisions made with the coin do have a 50:50 chance?

My suggestion is that you think about what happens if you toss the coin twice. Work out the possible combinations of outcomes, and their probabilities.

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