Madinat al-Muslimeen Islamic Message Board
| Brainiac |
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| AbuKhaled |
| 08/22/00 at 13:43:45 |
| Assalam alaikum wa rahmatullah to you all, I thought I'd try and start in the best possible way, and give you all something memorable. ;-) For those of you who might balk at the fond nostalgia of the last occcasion I posted something like this, fear not, this is straightforward; just extremely tough (well, for most people anyway). There is no trick, it just requires a good ability to think laterally, and reason sharply. The information provided is as much as is needed to solve it. My malicious nature :-) means that I want my brothers and sisters to "enjoy" this as much as I did, lol. Its one of those ones that doesn't seem obvious, to the point of making you doubt that it can be done legitimately, so you begin looking for some kind of loophole, and then when you're told the answer you are impressed by its ingenuity. Either that, or I'm *really* thick! Lol. Ma'assalam, Abu Khaled PS: No need to thank me ;-) --------------------------- Four men are buried up to their necks and about to be put to death by firing squad. They are arranged so Man A is facing a brick wall which is between him and Man B. Man B is facing the opposite side of the wall. Behind Man B is Man C and behind Man C is buried Man D. No-one can turn their head to look behind them so, Man A and Man B can only see their resepctive side of the wall in front of them, Man C can see only Man B and Man D can see Man C and Man B. A hat is placed on the head of each man. Man A's hat is white, Man B's is black, Man C's is white and Man D is black. Each man knows that there are a total of two black hats and two white hats, but they do not know the colour of their own hat. They are given three minutes to try to work out the colour of their hats. They are not allow speak to each other, just to shout out the colour of their own hat. If they guess right they live. It can be done. You're time starts now... |
| Re: Brainiac |
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| bhaloo |
| 08/22/00 at 15:32:05 |
| Asalaam alaikum wrt wb, Welcome aboard Abu Khaled, good to see you posting, and you even started off with a lateral thinking puzzle!!! LOL, hahahahaha :) I remember what happened last time. The rest of your jokes are funny, but I have heard of them before, you'll have to find some new ones. ;) Hmmm, this puzzle seems difficult, but I have a solution that will work, but I doubt its the answers. It couldn't possibly be the answer, my solution is sort of silly but it works. Ok, don't laugh too much here I go. Let me draw a picture to illustrate the example. D-black hat C-white hat B-black hat ------wall------ A-white hat Analysis: In order for anyone to answer they must know what the other 3 are wearing. D knows what C & B are wearing (2 people) C knows what B is wearing (1 person) B knows nothing A knows nothing This is really all the information we are given, except that there is a wall separating A and B. How high is this wall? High enough that it prevents us from seeing the other person(s) on the other side of the wall. My solution requires that person A is wearing a hat such that it can be seen on the other side of the wall, but at the same time we can not see person A (just his hat). So person D sees person C's white hat, person B's black hat, and person A's white hat, therefore person D says BLACK. Person C then goes and he sees person B's black hat and knows person D said black, so he says WHITE. Person B knows that person D has a black hat, person C has a white hat, he sees person A's white hat, so he says BLACK. Person A then says WHITE, because that is the only possibility remaining. |
| Re: Brainiac |
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| Arsalan |
| 08/22/00 at 17:11:16 |
| Assalamu alaikum wa rahmatullahi wa barakaatuh. Abu Khaled, welcome aboard! Glad to see you back. Arshad's answer is nice, but he assumed something, i.e. the hat of A is high enough to be seen on the other side of the wall. I don't think any such assumptions need to be made, because all the needed information, as Abu Khaled said, is given. Here's my take at it. I'm gonna use Arshad's drawing, because I think it helps the visual mind: D-black hat C-white hat B-black hat ------wall------ A-white hat Analysis: If B and C were both wearing black or white, then D would immediately know that his hat must be the opposite, because there's only two of each color out there. But he sees one white and one black, so he cannot tell whether his hat is black or white. It could be either one! C is smart. He realizes that D is confused, and that's why he hasn't shouted out any color yet, even after several moments have elapsed. Immediately, C realizes that D's confusion is due to him seeing two DIFFERENT hats on C and B. C sees that B is wearing black, and thus his hat must be WHITE (in order to confirm D's confusion)!!! "Hurrah," he shouts, "I have WHITE!" He is saved and taken out of the sand. Now everyone knows that there are 2 blacks and one white remaining. The situation, now is this: D-black hat B-black hat ---wall----- A-white hat Poor A cannot tell much from where he's at. He can't see anyone, and he can't even tell which man had just shouted "white" because there is no way for him to judge that from his position. He assumes that there is only one person (D) who has the most advantage among them because he can see TWO people, and that must be the person who had shouted "white." Of course, his assumption is wrong, but there's not much else he can tell from where he's at. Now, he realizes that the only way D would have said "white" so confidently is if he saw two black hats in front of him. And if D was wearing white, which was obvious since he had been saved, then A must be the other person wearing white. That is the only way. WHITE, shouts A. His assumption was wrong, but his answer is correct. He is saved. The others now know that there's only two people left and only black hats remain. They both shout "black" and are both saved. So...did I get it? |
| Re: Brainiac |
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| Arsalan |
| 08/26/00 at 02:31:30 |
| Assalamu alaikum, This disappearing act after posting a riddle is become a norm for Abu Khaled! Either that, or we should start praying that everything is ok with him! Wassalam. |
| Re: Brainiac |
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| bhaloo |
| 08/26/00 at 09:02:33 |
| Asalaam alaikum wrt wb, Arsalan, I was thinking of the same thing. Where is Abu Khaled? ??? Abu Khaled, if you are waiting for more people to reply to the riddle, its possible that they know you like making us "sweat", so they might have refrained from giving an answer. Oh come on Abu Khaled, just tell us the answer!!! :) |
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