Please help me solve this riddle...

Discussion in 'All Things Boats & Boating' started by Wynand N, Jun 12, 2007.

  1. Wynand N
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    Wynand N Retired Steelboatbuilder

    I am busy with some course and was presented with this riddle and needs to have an answer by Friday.

    You are flying in a plane and the pilot pointed to you an island ahead with a landing strip that forks at the end. He mentioned that the fork leads to a settlement of good people on the one side and to cannibals on the other side and also warned that the cannibals are big liars and deceivers.

    Just then the plane's engine let go and the pilot makes a crash landing on the island and the plane came to rest at the fork junction of the runway and you realize that you are the only survivor. When you stepped out of the plane there was a person standing at the fork junction....

    Now comes the crunch. You want to be with the good people who can help you but you do not know which side of the fork to take and you can ask this unknown person only ONE question to help/save you. What would it be?
     
  2. longliner45
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    longliner45 Senior Member

    whats for dinner?
     
  3. safewalrus
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    safewalrus Ancient Marriner

  4. jehardiman
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    jehardiman Senior Member

    There is no proper question as you phrased it. In order for there to be a correct question, the cannibals MUST ALWAYS LIE!!

    If that is the case then the question is....Hey! Who are you and what are you doing with that big pot?...No!...Wait!................
     
    Last edited: Jun 12, 2007
  5. SamSam
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    SamSam Senior Member

    Ask him if he wants the dead pilot.
     
  6. charmc
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    charmc Senior Member

    OK, try this.

    Assumptions:
    1. The cannibals/bad guys ALWAYS lie.
    2. The good people ALWAYS tell the truth.
    3. The left fork leads to the cannibal/bad village.
    4. The right fork leads to the "good guy" village.

    Ask, "If you were from the other village, not your own, which fork would you tell me to take to get to the "good guy" village?

    If he's a good/truthful guy, you're asking him what he would say if he were a liar. Being a truthful guy, he will say "left fork".

    If he's a cannibal/liar, you're asking him what he would say if he were a truthful guy. Being a liar, he'll say, "left fork".

    Either way, one question tells you to take the right fork. (If I figured this out right. Otherwise, you're screwed! :D:D )
     
  7. timgoz
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    timgoz Senior Member

    I'll go with Sam on this one. I'm stumped but also tired and if I exert to much mental energy thinking on this I'll get a headache.

    Tim
     
  8. jehardiman
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    jehardiman Senior Member

    There is a simplier solution....:D
     
  9. marshmat
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    marshmat Senior Member

    Charlie's solution would work just fine if the natives were all computer-controlled robots with precisely logical yes/no thinking..... but IMHO he'll confuse whoever he meets so badly that they'll just end up mulling it over long enough for you to fix the broken motor :D
     
  10. charmc
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    charmc Senior Member

    ???????????
     
  11. jehardiman
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    jehardiman Senior Member

    Check your PM's.

    I will post it my thursday AM. Lets see if any others have seen this before.
     
  12. MikeJohns
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    MikeJohns Senior Member

    Wynand

    It helps to reduce these sorts of problem to a simple logic table, draw a table of inputs and outputs then the pattern becomes a bit clearer. In this case you can consider the truth to be a one and a lie to be a zero


    Query Cannibal NiceBloke

    1 0 1
    0 1 0

    grouping the ones you get the truth from
    Not the Cannibal AND the Nicebloke

    Theres no ORs in the solution and the AND is the key it involves both the players so your query must somehow involve them both.

    By effectively passing the query through both parties you must always get the negative or the lie.

    You could try and incorporate the NOTs into the query to get a true answer but easier to ask a plain yes no and knowingly get the lie

    So make it a yes no question and do the opposite.

    Sorry it may all look a bit complex if you haven't studied logic but it is really easy once you get the hang of it. Unless you have no pencil then you end up as the fellow below :)
     

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    Last edited: Jun 16, 2007
  13. charmc
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    charmc Senior Member

    Jehardiman,

    You thought MINE was too complex?? :D :D
     
  14. hansp77
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    hansp77

    I know there is probably a logical answer for this, but,
    Ask him if the water is wet, if the sky is blue, or any other damn obvious question. If he answers yes, follow him home. If he answers no, wait and see which way he goes and go the other. If he has a cousin or some sort of Romeo and Juliet relationship happening in the other villiage, you might be in trouble.
     

  15. hansp77
    Joined: Mar 2006
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    hansp77

    While logically the whole,
    "If I asked a man from the other village if this was the road to the cannibal village what would he say ?"
    might make sense, in the practical situation, I just don't see it working.

    I think you might get some sort confused look and an answer like

    "huh? man from other village... what? I am man from village. Not other man. no other village... what?"
    And then you've blown your question.:D

    even if the islander understands your language, and your question properly (cause if he doesn't understand it, he could still answer truthfully or in a lie in a way unexpectable) you would still have to wonder about the logic of walking towards the village that the only person you could find said WAS the cannibal village!:D (I can just picture the after dinner conversation as they are sucking on your bones, "can you believe this guy? What a fool! I actually told him that this was the way to my cannibal village- Don't ask me why, I was still a little dazed from watching the plane crash! the damn fool grinned like a stupid monkey, and strolled on straight in! that was when you walked up and speared him in the back! I couldn't stop laughing... ahh... stupid bloody foreigner eh!"

    The other option is of course to just grab the dead pilot (par-cooked?) from the plane wreckage, throw him over your shoulder and pick any old path.
    If you arrive at the non-canibal village, you have appeared as a concerned friend who brought your buddy to be cared for and eventually buried,
    if you arrive at the cannibal village, well you have brought dinner, and after after offering him around, you indicate that you will just go and grab another one for desert, and slip off down the other parth to the other village.
     
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