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Who's the spy?

  1. Oct 19, 2004 #1
    3 men (A,B,C) were being courtmatialed.It was up to the judge to find which of the three was a spy.
    Now it was known to the judge that of the three men, one was a liar who never told the truth ,one was an honest man who never lied and the third ,the spy, sometimes lied but not always.

    Unfortunately the judge didnt know which was which.

    When asked A stated either that C was a liar either that C was a spy
    (We dont know his exact statement)

    When asked B stated either that A was spy either that A was a liar either that A was honest (Again we dont know the exact statement)

    Finally when C was asked he stated either that B was a liar either that B was honest either that B was a spy.

    The judge (who obviously knew the three exact statements) was able to discover the spy and convict him.

    Years later the case was told to a famous logician as written above.After some thought the logician declared that he could not figure out who the spy was.Then somebody told him A's exact statement and the logician was able to discover the spy.

    Who is the spy?
     
  2. jcsd
  3. Oct 19, 2004 #2
    ::B::

    -- AI
     
  4. Oct 27, 2004 #3
    The judge. lol
     
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