A riddle!

SerephelSerephel
edited July 2010 in General
A riddle! Please consider the following picture:

riddle.jpg

Shown above are 4 men buried up to their neck in the ground.
They cannot move; they can only look forward.
Between A and B is a brick wall that cannot be seen through.
They know that between them they are wearing 4 hats: 2 black hats and 2 white hats. They do not know which color they are wearing.
In order to avoid being shot, one of them must call out to the executioner the color of their hat. If they get it wrong, everyone will be shot.
They are not allowed to talk to each other.

Question: Which one of them calls out?

Question: Why is he 100% certain of the color of his hat?

This is not a trick question. There are no outside influences nor other ways of communicating. They cannot move and are buried in a straight line. So, A & B can only see their respective sides of the brick wall. C can see B, and D can see B & C.

And no cheating! We're going on the honor policy here.

Comments

  • illithid235illithid235
    edited July 2010
    I've seen the answer before, so I'll hold it in.
  • DaveyDavey
    edited July 2010
    I would say D sees B & C, and deduces that if they are wearing a white and a black hat respectively, then he also deduces that there must be a pattern, and so he calls out "white", and then C catches on and says "black", then B calls out his color, and A knows what his color is automatically, since he is the only one left.
  • NoLongerNoLonger
    edited July 2010
    A deduction is not 100% certainty, besides, it is just as trivial to guess a completely different pattern.


    Assuming it is not possible to to actually know with 100% certainty, then then answer seems simple enough.

    D sees both B and C's hats. He knows there are two of each hat, so if they are both wearing the same one he can be certain he has the hat of the opposite color. However this is not the case.
    B and C assume D will speak up first, and A knows he can make no assumptions.
    When D says nothing it is taken as an indication he can make no assumptions either. C now knows B and himself are wearing different colored hats, his being B's opposite.
  • ReallyCleanSocksReallyCleanSocks
    edited July 2010
    Yeah, he would only have a 50% chance of knowing if it was the hat he had. Also you're an idiot.
  • DaveyDavey
    edited July 2010
    I looked it up.
  • BehemothBehemoth
    edited July 2010
    What do you mean by it not being a "trick question"? Do you simply mean that it can be answered or that it is straight forward and has no stupid add-ons, like there's a hole in the brick wall? I would have to say that if the following assumptions are true, then it is impossible. The men have absolutely no information available to them other than the conditions of their potential execution, including that there are 2 black hats and 2 white hats and that there is a brick wall. Individually, That is all A and B know, C knows that B's hat is white and D knows that B's hat is white and C's hat is black. Is that correct?

    EDIT: And if NoLonger's answer is correct, then your premise was false. That is not 100% certainty. By which I assumed you meant 100% logically sound reasoning for his conclusion. After all, nobody can be certain that they aren't suffering from heat stroke and dehydration and seeing a black hat when it's really white.
  • X'o'LoreX'o'Lore
    edited July 2010
    It's exactly as NoLonger explained.

    C would speak up first. If B&C had the same color hat, D would be able to know what color hat he had and would speak up first, but since B&C are different colors D says nothing. C can then know that his hat is different from B's hat which he can see, so he knows what he has for a hat simply based on the fact that D said nothing.
  • SerephelSerephel
    edited July 2010
    By a trick question, it means that there aren't any variables left unmentioned or unsaid. A and B are not packing portal guns or anything. There was no mention of heat stroke or any other reason why people could not see what was in front of them, so you can safely assume that they can see clearly.

    And NoLonger is right.
  • BehemothBehemoth
    edited July 2010
    That's stupid.
  • SerephelSerephel
    edited July 2010
    You're stupid.
  • shakeycatshakeycat
    edited July 2010
    I figured it was C, but only because he was the only one with that colour hat on his side of the fence, not why.

    One of my favourite games is FANG DEN HUT!! It's like Risk for Germans
  • BehemothBehemoth
    edited July 2010
    I remember that game. It's called headache, by Milton Bradley. It has the pop-o-matic.
    Serephel wrote: »
    You're stupid.

    You're ugly.

    EDIT: And it's a stupid riddle because C didn't know there was somebody behind him who could see his hat and B's hat.
  • ApathyApathy
    edited July 2010
    It's a stupid riddle because who the hell buries people with dunce hats and threatens to shoot them?

    That's weirder than the premise of Motel Hell.
  • illithid235illithid235
    edited July 2010
    Behemoth wrote: »

    EDIT: And it's a stupid riddle because C didn't know there was somebody behind him who could see his hat and B's hat.

    Actually, that's a good point. It states that they know there's four of them, but how does C know that D isn't actually behind the guy on the other side of the wall?

© Vanilla Keystone Theme 2023