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Who has the key? (Posted on 2002-05-17) Difficulty: 2 of 5
An adventurer found a locked treasure chest in a dungeon. He tracked down three brothers (each either a Liar or a Knight) one of whom has the key to open the chest.

Each made a statement:

  • A: I have the key to the chest.
  • B: I don't have the key to the chest.
  • C: B Doesn't have the key.

    The adventurer knows that at least one of the three is a Liar, and at least one - a Knight. Who has the key?

  •   Submitted by levik    
    Rating: 2.9375 (16 votes)
    Solution: (Hide)
    If A had the key, he would be a Knight, but so would B and C. Since at least one of the three is a Liar, this cannot be.

    If B had the key, all three turn out to be Liars, and that is also impossible, since at least one is a Knight.

    Thus, it's C who has the key, making both him and B Knights, and A a Liar.

    Comments: ( You must be logged in to post comments.)
      Subject Author Date
    SolutionExplanation to Puzzle AnswerK Sengupta2022-06-09 23:01:33
    Puzzle AnswerK Sengupta2022-06-08 13:34:06
    SolutionAnswerMath Man2020-03-14 21:01:43
    SolAndre2010-06-04 17:13:15
    SolutionSolutionPraneeth2007-08-29 02:53:24
    SolutionPuzzle SolutionK Sengupta2007-03-18 04:12:45
    SolutionChance2006-06-01 21:17:57
    Answer in the key of C...Patrick2005-05-13 17:34:15
    SolutionSolutionStephen Ticsay2005-04-15 01:39:34
    Solutionplease ignoreFatBoy2003-10-03 12:02:11
    SolutionSolutionLewis2003-05-30 11:48:53
    DJ,I just... ...wanted to... it because... ...of so and so. OOOOOOOOOKKKKKKKKK? AGREEMENT?Tim Axoy2003-04-14 02:36:57
    i know the answerJonathan2003-03-26 06:52:41
    re: The key to --DJ2003-03-22 17:50:35
    SolutionThe key to CTim Axoy2003-03-22 02:33:36
    ahaHazirah2002-08-04 00:07:08
    i got itmarty2002-05-22 22:41:50
    SolutionEnder2002-05-17 07:13:04
    SolutionMy SolutionTomM2002-05-17 07:12:48
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