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An exercise from the book A Mathematical Introduction to Logic

  1. Apr 8, 2007 #1
    1. The problem statement, all variables and given/known data

    you are in a land inhabinated by people who either always tell the truth or always tell falsehoods. You come to a fork in the road and you need to know which fork leads to the capital. There is a local resident there, but he has time only to reply to one yes-or-no question. What one question should you ask so as to learn which fork to take?
    suggestion: Make a table.

    2. Relevant equations

    3. The attempt at a solution

    If I asked you 'does the right way lead to the capital?', would you anwser 'yes'?
    If the guy reply yes, take the right way. If no, the left.

    I am wondering if I am surposed to ask questions about 'future' here?
    What exactly does the writer mean by 'make a table'?
  2. jcsd
  3. Apr 8, 2007 #2


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    Science Advisor

    That's a perfectly good answer. As far as "make a table", I suspect it refers to having two columns, whether the right or fork is correct, and two rows, whether the person tells the truth or lies, when considering what results a specific question would get.
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