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Puzzle of the Month
=======================================The Traveller
=======================================
In the land of Truth Tellers and Liars, a traveller
comes to a fork in the road. One road leads to
safety and the other road leads to certain danger.
There is a man standing at the fork who knows the
area well. The traveller may ask him only one
question to find out the path to safety.
The traveller does not know if the man will lie
or tell the truth.
What question must he ask to get to safety?
Answer
This is the question the traveller asks:
If I would have asked you yesterday "which road do I take to safety?" what would you have said?
If he is the truth teller you have your answer.
If he is the liar, then he must lie about yesterday's answer (which was false), and therefore must give you the truth today!
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