blackdiamond Posted July 1, 2006 Author Report Share Posted July 1, 2006 I'd still like to know what was wrong with my solution. I've been over it a dozen times and it still works for me... -Q I might have misunderstood you, but there is one line in your solution that DOES NOT identify whether the coin is heavier or lighter. You MUST be able to tell which it is. Go through it again and help me if i've simply misunderstood your explanation (on that one point) and i'll apologise. Quote Link to comment Share on other sites More sharing options...
Capitalism Forever Posted July 1, 2006 Report Share Posted July 1, 2006 I'd still like to know what was wrong with my solution. I've been over it a dozen times and it still works for me... As blackdiamond said, you need to be able to tell if the counterfeit is too light or too heavy in EVERY case. There is one case in your solution where you cannot tell it. (Black has forwarded your solution to me ... after I sent him mine. ) BTW, your solution is almost the same as mine, so you're on the right track; there is only one branch of the decision tree that you'll need to correct. Quote Link to comment Share on other sites More sharing options...
Qwertz Posted July 3, 2006 Report Share Posted July 3, 2006 Oh yeah I knew about that. He cc'ed that to me, too, and I thought he meant it was completely wrong. I can't figure out how to tell in that one case, so I wouldn't mind being told. I just thought that maybe blackdiamond didn't think my answer worked at all. -Q Quote Link to comment Share on other sites More sharing options...
Capitalism Forever Posted July 3, 2006 Report Share Posted July 3, 2006 I can't figure out how to tell in that one case, so I wouldn't mind being told. Come on, don't give it up so easily! You're almost there! in that one case Just to make sure you don't misunderstand, it is true that you cannot say whether the false coin is too light or too heavy in the specific case we are talking about. The solution is to never arrive at that case, i.e. to do something differently in 2a. Quote Link to comment Share on other sites More sharing options...
blackdiamond Posted July 5, 2006 Author Report Share Posted July 5, 2006 Qwertz. did you solve the (easier) 27 balls one i gave to Aleph (above) for "practice"? This is not a terribly big clue, but i think if you solved that one, you can identify where your small mistake was for this one. (Sorry for giving you the impression that you were completely off track). if you still want the answer, PM me or CF. Quote Link to comment Share on other sites More sharing options...
blackdiamond Posted May 14, 2007 Author Report Share Posted May 14, 2007 Here's another brain teaser (let's see if I can revive my thread): What is black when you buy it, red when you use it, and gray when you dispose of it? PM me the answer if you have it, anyone (it's not a trick question; when I asked a friend of mine, his answer was "what." No, it's a real thing.) If anyone else has an interesting puzzle or brain teaser, please share it here and we'll PM the answer to you. Thanks, Black. Quote Link to comment Share on other sites More sharing options...
blackdiamond Posted May 14, 2007 Author Report Share Posted May 14, 2007 JOHN McVEY has got it! Quote Link to comment Share on other sites More sharing options...
blackdiamond Posted May 14, 2007 Author Report Share Posted May 14, 2007 The GROOVENSTEIN has got the [oops i almost said the answer here] question right! Quote Link to comment Share on other sites More sharing options...
blackdiamond Posted May 16, 2007 Author Report Share Posted May 16, 2007 MISLEIGH's finally got it too!!! The answer just CAME later, I'm told, without any "intentional thinking," after struggling with it a bit. I'm always interested in finding out how the brain solves problems like this one, especially what happened in MISLEIGH's case - and my case too. (Those who submitted the wrong answer, or have not got any answer yet but want to know it, you can PM me or the other people above who have got it so far, when you give up.) Quote Link to comment Share on other sites More sharing options...
blackdiamond Posted May 17, 2007 Author Report Share Posted May 17, 2007 ANOTHER INTERESTING ONE: On a wall are 3 standard on/off switches. One (and only one) controls a light bulb inside a light-tight, well-insulated closet. The other two switches do nothing. You can only open the closet door once, and cannot touch/change any switches after the door is open (or re-closed, for that matter). Damaging or disassembling the door, walls, or switches is against the rules. Within these constraints, can you determine with certainty which switch controls the light bulb? [PM Blackdiamond if you have the answer. That includes you too, Meta! ] Quote Link to comment Share on other sites More sharing options...
source Posted May 17, 2007 Report Share Posted May 17, 2007 (edited) Here's a puzzle: There are three prisoners in a prison, and they are given the chance to be released. Two or three prisoners will be released, but only if they can correctly guess what color hat they're wearing. The prisoners are given these hats according to this rule: There are either two white hats and one red, or two red hats and one white. They are then lined up so that one prisoner stands behind another. Each prisoner cannot see his own hat, but he can see the hats of those who are standing in front of him. Therefore, the first prisoner can't see anyone wearing hats. The second can see the first, and the third can see the first and the second. The prisoners have unlimited time to answer, and they do so by raising a hand and the providing the correct answer. If any prisoner offers an incorrect answer, all three prisoners are shot. If a prisoner doesn't want to answer, he stays in jail. Assuming that a prisoner will raise his hand to offer an answer as soon as he knows it, and they are completely rational, how can any two prisoners save themselves in any situation? In which cases is it possible that all three prisoners will save themselves? Edited May 17, 2007 by source Quote Link to comment Share on other sites More sharing options...
blackdiamond Posted May 17, 2007 Author Report Share Posted May 17, 2007 Only ALON and SOURCE have got the light bulb question right so far! Quote Link to comment Share on other sites More sharing options...
source Posted May 17, 2007 Report Share Posted May 17, 2007 Here's a puzzle: Sorry about this, but I forgot to mention that the prisoners must not communicate. Quote Link to comment Share on other sites More sharing options...
source Posted May 17, 2007 Report Share Posted May 17, 2007 BLACKDIAMOND solved it! Quote Link to comment Share on other sites More sharing options...
Capitalism Forever Posted May 19, 2007 Report Share Posted May 19, 2007 The prisoners have unlimited time to answer, and they do so by raising a hand and the providing the correct answer. Are we allowed to know what question the prisoners have to answer? Quote Link to comment Share on other sites More sharing options...
blackdiamond Posted May 20, 2007 Author Report Share Posted May 20, 2007 CAPITALISM FOREVER has solved the light bulb puzzle! Quote Link to comment Share on other sites More sharing options...
blackdiamond Posted May 20, 2007 Author Report Share Posted May 20, 2007 Are we allowed to know what question the prisoners have to answer? "Each of you - what colour is your own hat?" Quote Link to comment Share on other sites More sharing options...
source Posted May 20, 2007 Report Share Posted May 20, 2007 CAPITALISM FOREVER solved it! Quote Link to comment Share on other sites More sharing options...
mrocktor Posted May 21, 2007 Report Share Posted May 21, 2007 Not exactly a logic pussle, but a fun problem anyway: Three guys check into a hotel. Desk clerk tells them it is $30 for the night. After they go up to their room he realizes he's overcharged them, the room is only $25. So the desk clerk calls the bellhop over, tells him he's overcharged these three guys, gives him five $1 bills and sends him up to give them a refund. On the way up the bellhop gets thinking: There are three of them and five dollars. You cant divide three into five evenly. So he decides to keep two dollars, gives them three and goes on his way. So, the guys originally paid $10 each for the room. Then the bellhop gave them each a dollar back. Now they have paid $9 for the room. There are three of them: Three times 9 is 27 plus the two dollars in the bellhop's pocket is $29. What happened to the other dollar? Quote Link to comment Share on other sites More sharing options...
IAmMetaphysical Posted May 21, 2007 Report Share Posted May 21, 2007 The Gov't taxed it! Those bastards! Pmed you the real answer. Quote Link to comment Share on other sites More sharing options...
mrocktor Posted May 21, 2007 Report Share Posted May 21, 2007 The Gov't taxed it! Those bastards! Pmed you the real answer. Quote Link to comment Share on other sites More sharing options...
blackdiamond Posted May 22, 2007 Author Report Share Posted May 22, 2007 MISELEIGH has solved the light bulb puzzle! Quote Link to comment Share on other sites More sharing options...
source Posted May 23, 2007 Report Share Posted May 23, 2007 (edited) Not exactly a logic pussle, but a fun problem anyway: Whoops, sorry, posted a solution accidentally. Hope nobody read it... Edited May 23, 2007 by source Quote Link to comment Share on other sites More sharing options...
Groovenstein Posted May 23, 2007 Report Share Posted May 23, 2007 Not exactly a logic pussle, but a fun problem anyway: Whoever wrote that problem has a promising career in politics ahead of him. Quote Link to comment Share on other sites More sharing options...
mrocktor Posted May 23, 2007 Report Share Posted May 23, 2007 Whoever wrote that problem has a promising career in politics ahead of him. Sad, but true these days IAMMETAPHYSICAL, BLACKDIAMOND and SOURCE have no chance of a political career! (they solved the puzzle...) Quote Link to comment Share on other sites More sharing options...
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