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The New Coffee Room

  1. TNCR
  2. General Discussion
  3. Puzzle time - prisoners and hats

Puzzle time - prisoners and hats

Scheduled Pinned Locked Moved General Discussion
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  • KlausK Online
    KlausK Online
    Klaus
    wrote on last edited by
    #5

    That puzzle sounds familiar. Didn't we have that in the past?

    1 Reply Last reply
    • jon-nycJ Online
      jon-nycJ Online
      jon-nyc
      wrote on last edited by
      #6

      I don't think so. There are a number of 'prisoner hat' problems.

      The whole reason we call them illegal aliens is because they’re subject to our laws.

      1 Reply Last reply
      • jon-nycJ jon-nyc

        Possibly, but I think there are a lot of puzzles of this type.

        KlausK Online
        KlausK Online
        Klaus
        wrote on last edited by
        #7

        @jon-nyc said in Puzzle time - prisoners and hats:

        Possibly, but I think there are a lot of puzzles of this type.

        Such as these.

        Give me some more time. I know there are many "color of your hat" puzzles, but I'm pretty sure I've also seen one involving probabilities in the past. Maybe not exactly that one.

        1 Reply Last reply
        • KlausK Online
          KlausK Online
          Klaus
          wrote on last edited by
          #8

          I think I now remember where I saw the puzzle.

          There's a mathematician who publishes such puzzles on a regular basis, Peter Winkler. He has a monthly column in the "Communications of the ACM", of which I'm a subscriber. I believe I saw that puzzle there. If I think about the puzzle more, I may remember parts of the solution, so I guess I better just keep my mouth shut.

          1 Reply Last reply
          • HoraceH Offline
            HoraceH Offline
            Horace
            wrote on last edited by
            #9

            I guess the set of rules would attempt to clump wrong guesses together while right guesses would tend to be alone. The rules would also want to ensure that at least one person guessed.

            Education is extremely important.

            HoraceH 1 Reply Last reply
            • MikM Offline
              MikM Offline
              Mik
              wrote on last edited by
              #10

              If they were that smart they wouldn't be prisoners, now would they?

              "You cannot subsidize irresponsibility and expect people to become more responsible." — Thomas Sowell

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              • HoraceH Offline
                HoraceH Offline
                Horace
                wrote on last edited by
                #11

                Tell that to Stalin and his pogroms against intellectuals.

                Education is extremely important.

                1 Reply Last reply
                • HoraceH Horace

                  I guess the set of rules would attempt to clump wrong guesses together while right guesses would tend to be alone. The rules would also want to ensure that at least one person guessed.

                  HoraceH Offline
                  HoraceH Offline
                  Horace
                  wrote on last edited by
                  #12

                  @Horace said in Puzzle time - prisoners and hats:

                  I guess the set of rules would attempt to clump wrong guesses together while right guesses would tend to be alone. The rules would also want to ensure that at least one person guessed.

                  So, is the answer that simple? Those who see two different colors would not vote. If the other two people are same, guess opposite? This will cause any configuration of colors other than all-same to be a win (one correct vote), while all-same would be a loss (3 wrong votes).

                  Education is extremely important.

                  1 Reply Last reply
                  • KlausK Online
                    KlausK Online
                    Klaus
                    wrote on last edited by
                    #13
                    1. Do the prisoners know (or can determine) the order in which they are asked?
                    2. Can the prisoners hear all the answers?
                    1 Reply Last reply
                    • KlausK Online
                      KlausK Online
                      Klaus
                      wrote on last edited by
                      #14

                      Oh, I think I now remember the key to the solution. The probability can be raised to 75%.

                      1 Reply Last reply
                      • HoraceH Offline
                        HoraceH Offline
                        Horace
                        wrote on last edited by Horace
                        #15

                        Yes that is the % of my proposed solution. I got there by figuring that each guess would be 50/50 so the rules would have to clump wrong guesses together and single out right ones. One such set of rules leaves 75% of color combinations yielding one right guess.

                        Education is extremely important.

                        1 Reply Last reply
                        • jon-nycJ Online
                          jon-nycJ Online
                          jon-nyc
                          wrote on last edited by
                          #16

                          I got the same answer as Horace.

                          Official answer comes out Saturday but I cant see them improving on 75%.

                          The whole reason we call them illegal aliens is because they’re subject to our laws.

                          1 Reply Last reply
                          • KlausK Online
                            KlausK Online
                            Klaus
                            wrote on last edited by
                            #17

                            It gets interesting if you generalize the number of prisoners and/or the number of colors.

                            https://arxiv.org/abs/cs/0509045

                            1 Reply Last reply
                            • jon-nycJ Online
                              jon-nycJ Online
                              jon-nyc
                              wrote on last edited by
                              #18

                              Oh man, you ruined the bonus round. 😉

                              The whole reason we call them illegal aliens is because they’re subject to our laws.

                              1 Reply Last reply

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