Problem of the Month
Who's Telling the Truth?
Two tribes live in an island. Those who live on the western side always tell the truth and those who live on the eastern side always lie. A scientist who visits the island hires a native in the center of the island as a guide to help her get around, but she only wants to keep him if he is a truth-teller. She thinks of a plan and says to him:
"Please, go ask that other native over there in the distance which side he lives on." When the guide returns he tells the scientist: "He said he lives on the western side." Did the scientist keep him as her guide? How can you determine if the guide was a truth-teller or a liar?
For the answer (try not to look right away!).
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