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What color hat do you have on ?

  1. Apr 1, 2007 #1
    i hope this wasnt already asked. i couldnt find it anywhere.

    you and 2 others are placed in a room with blindfolds. a hat is placed on each of you. it is either red or black. the blindfolds are then removed. you are told to stand if you see a red hat. everybody stands, while obeying the command. you see 2 red hats. what color hat do you have on ? if you are correct, you run to become the new king. if you are incorrect, you are promptly executed.
  2. jcsd
  3. Apr 1, 2007 #2


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    I have no idea.

    Now, if I knew the other two people are also given this choice, want to be in the running to be king, and have a decent reasoning capability, I'd have a better idea... :wink:
  4. Apr 1, 2007 #3
    hi hurky,

    thanks for not giving away the answer so soon. gosh i just posted it a couple minutes ago. you guys are too smart.
  5. Apr 1, 2007 #4


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    Well, this is one of the classics -- a lot of us have seen it before.

    And we have a convention over here: we write our answers in white (technically, color #ededed), so that you cannot see the answer we give unless you hightlight it with the mouse.
  6. Apr 1, 2007 #5
    i noticed a few answers were in white, and i was having a hard time reading them. that's cool.

    these were 3 puzzles that i liked - in the past few years.

    i was jumping up and down when i got the marble one, because it took me a long time to get it. but i did so with no clues whatsoever, so it was very satisfying for me when i did finally come up with it. you can go thru quite a few gyrations, before you stumble onto the answer. and i have to admit - i would call it stumbling, in my case. i felt sorta lucky to have gotten it.

    the cannibal one took me about an hour or so. the hat one is really less involved. it is solvable in a minute, if you happen to be thinking correctly - in it is really just one thought that you need.

    the marbles and cannibals involve several steps.
  7. Apr 2, 2007 #6
    this puzzle has been posted , a few times ... its always fun to do though .
  8. Apr 2, 2007 #7
    Dont you have a red hat too?
  9. Apr 3, 2007 #8


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    So what's the answer? Can't I wait and see if any of them are executed first? I hope the room isn't lit by a red light bulb.
  10. Apr 3, 2007 #9
    hi mk,

    no, it is not a silly answer. it takes a little thinking "outside of the box", but it is very answerable, with just the information given.
  11. Apr 3, 2007 #10
    >Assuming the other 2 aren't idiots, you have a red hat. If they don't figure their's out quickly.

    First assume you have a black hat, if you have a black hat then the other two would only see the red hat on eachother's head. Knowing that eachother can't see their own, they realise they themselves must have a red hat.

    Since neither person quickly realised his color it means that you must have a red hat as well, else they'd know theirs and had said it already.

    I explained that badly I think, it'd be a bummer if they were idiots.
  12. Apr 4, 2007 #11
    hi ge,

    yes, that is the correct answer, if i am following you correctly.
  13. Apr 4, 2007 #12
    Told ya I explained it badly :-).
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