1. Standard memberNatural Science
    blunderer of pawns
    Rhode (not an)Island
    Joined
    17 Apr '04
    Moves
    24785
    06 Oct '06 12:384 edits
    Here's the situation:

    Four men are tied to chairs in this configuration: (the arrows denote which way the men are facing.)

    Man ---) Man ---) Man ---) (Wall) (--- Man

    These are the instructions the men have been given:

    1. Each of you is wearing a hat. Two of you are wearing a blue hat, two of you are wearing a red hat.
    2. In order to save yourselves, one of you must correctly identify the color of your own hat.
    3. You are not allowed to tell anyone else what color their hat is.
    4. You have 10 minutes for one of you to positively identify the color of his own hat. After 10 minutes, or after a wrong guess, a bomb will go off. The bomb will also go off if anyone cheats.

    Because of the manner in which they are tied, none of the men can see what's behind them; they can only see forward. The lone man on the one side of the wall, obviously, cannot see any of the other men. Also, none of the men can take off their hat to identify it. Obviously, any of the 4 of them can take a guess and have a 50% chance of being right. But how can one of them deduce, with 100% certainty, the color of his own hat, given the rules laid out?
  2. Joined
    28 Nov '05
    Moves
    24334
    06 Oct '06 12:59
    Originally posted by Natural Science
    Man ---) Man ---) Man ---) (Wall) (--- Man
    call them A,B,C,D from left to right

    either B and C are wearing the same colour, in which case A can tell he is wearing the other colour,

    or B and C are wearing different colours, so A says nothing.
    B then knows C has a different colour to B,
    so B knows what he is wearing the other colour than C is wearing.
  3. Earth Prime
    Joined
    16 Mar '05
    Moves
    35265
    07 Oct '06 15:21
    Originally posted by aging blitzer
    call them A,B,C,D from left to right

    either B and C are wearing the same colour, in which case A can tell he is wearing the other colour,

    or B and C are wearing different colours, so A says nothing.
    B then knows C has a different colour to B,
    so B knows what he is wearing the other colour than C is wearing.
    if B and C are different, they can figure it out, but how does A and D determine what they have?
  4. Standard memberAThousandYoung
    or different places
    tinyurl.com/2tp8tyx8
    Joined
    23 Aug '04
    Moves
    26660
    08 Oct '06 08:14
    Only one person needs to figure it out.
  5. Standard memberNatural Science
    blunderer of pawns
    Rhode (not an)Island
    Joined
    17 Apr '04
    Moves
    24785
    08 Oct '06 12:12
    Againg Blitzer has the correct solution.
  6. Joined
    21 Oct '05
    Moves
    9139
    10 Oct '06 20:462 edits
    The middle person on the left side of the wall can say with 100% certainity. If the first two persons are wearing the same hat then definelty the last person has the answer but if doesnt then the middle one is wearing the opposite color cap from the guy who is sitting in front of him.
  7. B is for bye bye
    Joined
    09 Apr '06
    Moves
    27526
    10 Oct '06 21:17
    You can still do this if you add a third hat of one colour (and discard it after shuffling them and 'dealing' them onto people's heads).
  8. In your face
    Joined
    21 Aug '04
    Moves
    55993
    10 Oct '06 22:32
    Well if one man has to identify the colour of their own hat and each man can take their hat off and look at it then surely te rest follows?
    Am i missing something, again. 🙂😕
  9. Standard memberXanthosNZ
    Cancerous Bus Crash
    p^2.sin(phi)
    Joined
    06 Sep '04
    Moves
    25076
    11 Oct '06 01:00
    Originally posted by jimslyp69
    Well if one man has to identify the colour of their own hat and each man can take their hat off and look at it then surely te rest follows?
    Am i missing something, again. 🙂😕
    "Also, none of the men can take off their hat to identify it."
  10. B is for bye bye
    Joined
    09 Apr '06
    Moves
    27526
    11 Oct '06 01:01
    That they are tied to the chairs including their arms (and therefore cannot reach up to grab their hats).

    Also, it is important to note that these are the most intelligent people on the planet (all Guttersnipes) and for the purposes of this riddle, they don't tell each other anything - knowing that they are all brainy enough by themselves.
  11. B is for bye bye
    Joined
    09 Apr '06
    Moves
    27526
    11 Oct '06 01:041 edit
    Grrrr....
  12. Standard memberCalJust
    It is what it is
    Pretoria
    Joined
    20 Apr '04
    Moves
    66654
    11 Oct '06 10:49
    Originally posted by Gastel
    Grrrr....
    What do you have to edit if you just say Grrrr....???
  13. Subscribersonhouse
    Fast and Curious
    slatington, pa, usa
    Joined
    28 Dec '04
    Moves
    53223
    11 Oct '06 11:58
    Originally posted by CalJust
    What do you have to edit if you just say Grrrr....???
    Figuring out if it's supposed to be Grrr or Grrrr......
  14. Standard memberCalJust
    It is what it is
    Pretoria
    Joined
    20 Apr '04
    Moves
    66654
    11 Oct '06 12:08
    Originally posted by sonhouse
    Figuring out if it's supposed to be Grrr or Grrrr......
    In that case, your edit definitely improved it!
  15. In your face
    Joined
    21 Aug '04
    Moves
    55993
    11 Oct '06 21:14
    Originally posted by XanthosNZ
    "Also, none of the men can take off their hat to identify it."
    Not what what it said last time I read it. 4 edits?
Back to Top

Cookies help us deliver our Services. By using our Services or clicking I agree, you agree to our use of cookies. Learn More.I Agree