EPTPuzzleing Question! (HARD) - Page 52
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Catyoul
France2377 Posts
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Catyoul
France2377 Posts
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MoltkeWarding
5195 Posts
On November 23 2004 14:47 Catyoul wrote: You're forgetting the 2 that are at each extreme. They turn once max. Somewhere in Northern Eurasia, a group of 20 lemmings is planning a special group suicide this year. Each of the lemmings will be placed in a random position along a thin, 100 meter long plank of wood which is floating in the sea. Each lemming is equally likely to be facing either end of the plank. At time t=0, all the lemmings walk forward at a slow speed of 1 meter per minute. If a lemming bumps into another lemming, the two both reverse directions. If a lemming falls off the plank, he drowns. What is the longest time that must elapse till all the lemmings have drowned? Says nothing about 1 at each end. Yes I realize im making this fuss because Im too lazy to work on the problem as it was meant to be solved  | ||
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KarlSberg~
731 Posts
On November 23 2004 14:45 MoltkeWarding wrote: In that case the SCV was going at SCV velocity, tank going at Tank velocity. When SCV contacts tank they turn and move. However they occupied the same space so when they turned they contacted each other again and kept spinning in circles indefinitely while neither changed their position. Nada could not get unstuck on the ramp and nada had to kill them both  Eh eh. Yeah but these lemmings can't get bugged. When they meet another one, they instantly turn around and go the other way, they don't get stuck. I think I see what you mean, once 2 lemmings meet, they turn infinitely since whatever direction they face, they always face the other one. This is smart objection and I don't know how to answer it in a simple way. So let's just say the lemmings have a size, but this size is small enough to not matter regarding the length of the board. | ||
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Catyoul
France2377 Posts
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MoltkeWarding
5195 Posts
On November 23 2004 14:57 Catyoul wrote: I mean there is one who is extreme left of the pack of all the lemmings (almost wrote zerling there) and one extreme right. Even if they all perfectly stack (which is totally out of question), the half that looks left won't see any other lemming on the left and walk left and never see a lemming and the ones who look right won't see any other lemming on the right and walk right and never see a lemming either. That's why I asked if they occupied any physical space If they have a "left most" and "right most" they have to occupy space no matter how small and therefore confound the calculations.Anyway I'm going to try to work on this problem as its meant to be solved now | ||
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IceLeY
Germany121 Posts
Frank & Daniel meet after some time. Frank: Hi Daniel, how old are your three children now? I forgot it. Daniel: The product of their ages is 36. Frank: Oh, that doesn't get me far. Daniel. Hm, the sum of their ages equals my house number. Frank: Well... Daniel: Not to mention that the oldest one has blue eyes. Frank: Ah, ok, no i know how old they are. How old are the three children? | ||
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MoltkeWarding
5195 Posts
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Catyoul
France2377 Posts
1) 1*1*36 and 1+1+36=38 2) 1*2*18 and 1+2+18=21 3) 1*3*12 and 1+3+12=16 4) 1*4*9 and 1+5+9=14 5) 1*6*6 and 1+6+6=13 6) 2*2*9 and 2+2+9=13 7) 2*3*6 and 2+3+6=11 8) 3*3*4 and 3+3+4=10 After the 2nd info, he still doesn't know so it can only be 5 and 6. The 3rd one tells us there is an oldest one so it is 6 : 2 2 and 9 | ||
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Catyoul
France2377 Posts
On November 23 2004 15:04 MoltkeWarding wrote: Hmm im guessing 12750 seconds. Anyone else got this? Not me at least :p | ||
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KarlSberg~
731 Posts
On November 23 2004 15:04 MoltkeWarding wrote: Hmm im guessing 12750 seconds. Anyone else got this? They are much older than that. The younger is about 65 000 ooo seconds old, the elder is about 300 000 000 seconds old. But I'm not gonna tell how many years that means. EDIT: Ok that actually means what Catyoul wrote. | ||
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MoltkeWarding
5195 Posts
On November 23 2004 15:07 Catyoul wrote: 8 possibilities at first : 1) 1*1*36 and 1+1+36=38 2) 1*2*18 and 1+2+18=21 3) 1*3*12 and 1+3+12=16 4) 1*4*9 and 1+5+9=14 5) 1*6*6 and 1+6+6=13 6) 2*2*9 and 2+2+9=13 7) 2*3*6 and 2+3+6=11 8) 3*3*4 and 3+3+4=10 After the 2nd info, he still doesn't know so it can only be 5 and 6. The 3rd one tells us there is an oldest one so it is 6 : 2 2 and 9 Heh...I thought that the guy didnt know his house number either. No wonder I didnt get it :S | ||
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Catyoul
France2377 Posts
 Karlsberg, good one  Btw, you forgot a couple of zeroes for the younger | ||
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MoltkeWarding
5195 Posts
A woman can give birth every 9 months, and a child 9 months over 6 years is still 6. Or it could be twins, in which case the first twin "born" is considered the oldest, if only by seconds | ||
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KarlSberg~
731 Posts
On November 23 2004 15:12 Catyoul wrote: Karlsberg, good one France raised me in the love of fine maths too. :p | ||
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MoltkeWarding
5195 Posts
My time was referring to the lemmings question not the age question BTW :/ | ||
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ANewBeginning
Sweden21 Posts
At first when we don't know anything we have four possible solutions Bb Bg Gb and Gg. Here it is 25% for 2 boys 50% for boy girl and 25 % for 2 girls. BUT when we se the little brat girl at the door we know that there is a 100% possibility for atleast 1 girl. Since we don't know if she is the older or the younger sibling Bg Gb and Gg are the possible solutions which leaves us with 2/3 possibility of the other sibling being a boy. So I join the 2/3 crowd, someone from the 50-50 camp tell me where my reasoning is faulty, or atleast copy paste if an answer has already been posted (thread is to big to read :/). | ||
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KarlSberg~
731 Posts
*************** SPOILER ****************** When a lemming meets an other lemming they both change directions. When lemming A and B meet, after they meet lemming A will go in the direction lemming B went before they met. Lemming B will go in the direction lemming A went before they met. So as a whole when 2 lemmings meet, it's like nothing happens. The problem would be the same if lemmings could go across each other without ever changing direction. As a consequence the maximum time is the time a lemming takes to go across the whole platform: 100 seconds. | ||
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Catyoul
France2377 Posts
On November 23 2004 15:29 ANewBeginning wrote: Hmm so much bickering about that child problem :D, Im gonna try it to At first when we don't know anything we have four possible solutions Bb Bg Gb and Gg. Here it is 25% for 2 boys 50% for boy girl and 25 % for 2 girls. BUT when we se the little brat girl at the door we know that there is a 100% possibility for atleast 1 girl. Since we don't know if she is the older or the younger sibling Bg Gb and Gg are the possible solutions which leaves us with 66% possibility of the other sibling being a boy. So I join the 2/3 crowd, someone from the 50-50 camp tell me where my reasoning is faulty, or atleast copy paste if an answer has already been posted (thread is to big to read :/). IIRC, read my post on bottom of page 8, on page 10 for a more detailed version and on top of page 12 for an east way of seeing how it would have been 2/3. | ||
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KarlSberg~
731 Posts
On November 23 2004 15:29 ANewBeginning wrote: So I join the 2/3 crowd, someone from the 50-50 camp tell me where my reasoning is faulty, or atleast copy paste if an answer has already been posted (thread is to big to read :/). Refer to my own posts from page 32 to 34 or so. Catyoul and RoTaNiMoD around page 9-10. And a few other which I hope will forgive me for not naming them. | ||
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