Two Prisoners, Two Coins
A prison guard gives two prisoners a chance at freedom. He gives them the choice to play in the following game:
The two prisoners (let's call them A and B) will be imprisoned in separate cells, each with a fair coin.
In each round of the game, a guard will come to each prisoner's cell. The guard will have the prisoner flip his coin, tell him the result, and then ask him what the other prisoner flipped.
- If they both guess correctly, they will be instantly released.
- If neither of them guesses correctly, they will both be executed immediately.
- If one of the two prisoners correctly guesses what the other flipped, they have passed that round.
- If they are able to pass 1000 rounds in a row, they will be released.
If they choose to play, they will be given a brief moment to come up with a strategy together. They are tired of living in prison, but they definitely don't want to be executed. Should they choose to play?
Source: unknown
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