The seesaw itself is a lever. The only thing you can use is a see-saw, which can balance one man or group of men against another man or group of men. 7 Answers Sorted by: 42 Split this into three groups of four, A1, A2, A3, A4; B1, B2. If they are equal, A4 is heavier. Bottom line? Seesaw is the best interactive learning platform for PreK-5. If these are equal, the different man is 12. 1 v 12). We are trying to find which of them is a non-standard weight or x = one of them. The best answers are voted up and rise to the top, Not the answer you're looking for? Each islander is given a position to sit on the seesaw for each round. Are you sure you want to create this branch? New comments cannot be posted and votes cannot be cast. are patent descriptions/images in public domain? Can a VGA monitor be connected to parallel port? That person is the heavier (or lighter). :p, haha yeah loved the episode! If the unknowns go down, you know that one of them is heavy. So, what is the 12 people on an island riddle and what is the answer? Before that I didnt really get what you were doing. Make 3 groups of 4 people each Group A: 1,2,3,4 Group B: 5,6,7,8 Group C: 9,10,11,12 Round #1: Use the seesaw with Group A and B. Weigh 9, 10, 11 vs 1, 2, 3. If the seesaw reverses, ether 4 or 5 is the oddly weighted one. Now, weigh the remaining eight men on the seesaw, four on each side. Solution: The minimum number of times seesaw will be needed is 3. I believe it was in. A seesaw is binary. Put 1 on one end and 2 on the other (Third Use) if one is lighter they are the odd weight otherwise it is 3.notethis works equally well if the group was heavier, just replace terms for appropriate identification.'. If they are the same, 8 is the one we are looking for (and lighter). So in principle, we should be able to solve the problem. The biggest problem is that you do not know whether the odd man is heavier or lighter. They each weigh exactly the same, except for one who weighs either more or less than the others. (Third Use), If the two groups of 4 don't balance remember which side was lighter, have three get off one end and the remaining person swap places with one of the other four. One of two things will happen: 1) They are equal. (Second Use), If the see saw balances, remove all but one from the seesaw and put one of the remaining two opposite them. I like this answer other than the fact that if "Condition 2.1.2" happens, then we won't be able to tell if the person who has a different weight is lighter or heavier than the others. There are no scales or other weighing device on the island. seesaw: R1 L2 L3 L4 L1 S2 S3 S4 (heavy) (Second Use), If the see saw balances, remove all but one from the seesaw and put one of the remaining two opposite them. Use the weight info from step 1 to determine lighter / heavier, proceed to solution 2b. And there you have it! 2150 Condos - West Tower Phase 2 L: sit on the left, R: sit on the right, -: don't sit on the seesaw.. now compare L2 and L3. we weigh S1 against S2; if balanced it is S3 - else it is the heavy of S1 and S2. And if they are, then weigh 9, 10, 11 vs 1, 2, and 3. If one is heavier they are the odd one otherwise it is 6. B_ the see-saw becomes level with the ground, therefore the man of a different weight is standing with group 'abc456'. 12 men live on an island. There are 12 men on an island. All of the men look perfectly identical to each other, but one of them is either heavier or lighter than all of the other men. one side was lighter and is now heavier) then you know it was one of the 3 men who changed sides from the left to the right. -v, 1 split the 12 islanders into three groups Me and my wife sat down to try and solve the "12 islanders riddle" from Brooklyn Nine Nine, this is our solution. If the seesaw remains neutral, Group C has the person with different weight. Wow how did this even get 8 upvotesmind boggling. test all the cases: go test . What are some tools or methods I can purchase to trace a water leak? However only three measurements are allowed. How to delete all UUID from fstab but not the UUID of boot filesystem. Was Galileo expecting to see so many stars? we now know that the heavier islander are amongst S1 S2 S3. Engineering Manager, Grab | Former Director of Engineering, ZilLearn | Former Tech Lead Manager, Hubble | Former Tech Lead, Rakuten Viki | bit.ly/weiyuan. One of two things will happen: The seesaw will be perfectly balanced. There is an island with 12 islanders. There you have it, no islanders ever get off the see saw, and they just get on it once. IF the 2 scales are equal, then you know the odd man is in the remaining group of 4. Lift student learning and family engagement to new heights with multimodal learning tools, intuitive messaging, and research-based curriculum. If the seesaw balances we know that either 1 or 2 or 3 is oddly weighted. Use the weight difference from step 1 to determine heavier lighter. There is also a see-saw on the island. You can weigh three combinations of men on the see-saw. Press question mark to learn the rest of the keyboard shortcuts. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. (seesaw measurement number 3), (first make sure you have the heavy side on the left), seesaw: L1 L2 L3 L4 (heavy) R1 R2 R3 R4 I wonder if this is the highest-viewed duplicate question of all time? I am just looking for a little tweak to this answer. Find out the minimum number of times the seesaw will be used. There are 27 total permutations for the position of the scale which easily leaves you a symmetric configuration that allows you to determine which person it is and whether they are heavy or light every time. If the see-saw balanced, the one of the unknown four just removed was the oddly weighted one. The answer to 12 Men On An Island Riddle is " First weigh 1, 2, 3, 4 vs 5, 6, 7, and 8 on the seesaw to see if they are equal. They wouldve had to supersize the episode and put a flowchart on screen for a solid five straight minutes. The island has no scales but there is a see-saw. The pattern for all islanders is below: person: A B C . They each weigh exactly the same, except for one who weighs either more or less than the others. ((, Please explain your claim that is was not asked properly. The exciting catch? if balanced it is S3 - else it is the lighter of S1 and S2. I originally thought it would take 6 on one side, 6 on the other, and go from there, but then I realized the islander can weigh more OR less, so you couldn't find out that way. One problem - you have to figure out which person it is too. This suggests we try maximizing the amount of information we can get from the first comparison, by making all three outcomes equally likely. You can figure out both in three steps. 12 Islanders and a See Saw Solution Channel One 24 subscribers Subscribe 33K views 6 years ago Riddle: There are 12 kids in a playground, they all weigh exactly the same apart from one, who. The whole lighter OR heavier is the big monkey wrench here. All our articles and reviews are written independently by the Netmums editorial team. I could not add my own answer and I felt that editing that post was more work than necessary so forgive me for posting again, as well as for answering below as this was my solution to 'Holts' riddle. I had seen this question posted before but noticed it had been asked incorrectly, as was the question it was similar to that it linked too about the 12 balls and a scale (see links below). The seesaw will NOT be perfectly balanced. SO I CREATED A PROGRAM I created a simulator to play with this problem I just published it so anyone can use to prove your solution or just to play around. sideline: S1 R2 R3 R4, we know that the light islander is amongst R2 R3 R4 (seesaw measurement number 3). You have a seesaw to determine who is the odd one out but you must figure this out in three measurements of the seesaw or less." The seesaw will balance perfectly. to use Codespaces. Are there basic weighing puzzles requiring adaptive strategies? Ackermann Function without Recursion or Stack. You can only use it three times. Your aim is to find out which person weighs a different amount. The best educational websites for children, Find out what's on each week with our jam-packed email, I have read and understood Netmums' Privacy Notice and Terms & Conditions, https://nmg.netmums.com/header/activities/, https://www.netmums.com/esi/video/false/position:ATF, https://www.netmums.com/esi/mostactivechat/website/article. Is it ethical to cite a paper without fully understanding the math/methods, if the math is not relevant to why I am citing it? I gave each of the 12 men a letter, A-L. Can You Solve the Brain Teaser of the 12 Men and a See-Saw? Weigh them against each other. Happy problem solving. You must figure out which. b) If 1,2,5,6,7 is lighter, then one of 5,6,7 is different and lighter. How is "He who Remains" different from "Kang the Conqueror"? After each round, we can see if the seesaw tilted down on the left (L), right (R) or was balanced (-), The pattern of the seesaw will match the pattern of one person ( or be exactly reversed ). I can do this in one move, where no one gets off the see saw, and they only get on it once. It is a good write up though. If nothing happens, download GitHub Desktop and try again. Use 2 - Remove six(6) men from the see-saw, three(3) from both groups. now compare R2 and R3. Is it possible to measure 1 kilogram of sugar? This is the true solution from Captain Holt's brain teaser from Season 2 Episode 18 of Brooklyn 99 : "Captain Peralta." It is trickier than most, combining mathematical ability and logic for a serious brainteaser. Another coin weighing puzzle. Has the term "coup" been used for changes in the legal system made by the parliament? Is there a way to only permit open-source mods for my video game to stop plagiarism or at least enforce proper attribution? 42 votes, 14 comments. Presented below is a simpler solution. Now put 7 on one end and 8 on the other. Each islander is given a position to sit on the seesaw for each round. The ice cube and the basketball have the same weight. There are 12 men on an island. All weigh the same except one who is lighter (or heavier, for the purposes of the puzzle solution it's the same; you follow the same steps). Eleven weigh exactly the same amount, but one of them is slightly lighter or heavier. Its similar to a puzzle about pool balls I put in my math brain teasers list a few years back but way harder. Can you solve the classic 12 marbles riddle? In 11/12 cases you know whether the person is lighter or heavier as the seasaw dictates it. Let's say 'abc' and '456'. Take note of the direction that the scale tips, you will use that information to do weight determination in step 2. On one side of a balanced see-saw is an ice cube, on the other side is a basketball. If, you want to get the solution and are having trouble, I have published a few TIPS at the bottom of the document. Thus in principle we can get log227 bits from the three comparisons. Can patents be featured/explained in a youtube video i.e. Jordan's line about intimate parties in The Great Gatsby? Learn more. Have something to tell us about this article? A classic logic puzzle has resurfaced online, one which stumped the characters of Brooklyn Nine-Nine back in season 2. There are 12 men on an island. (named after their starting position, L1 = Left 1, R1 = Right 1, S1 = Side 1 etc..), We now know that the odd islander are amongst S1 S2 S3 S4 12 Islanders Teeter Totter Riddle There is an island with 12 islanders. c) If they are the same, then one of 3,4 is different. It is impossible to know both for sure in only three steps.). There is a seesaw to determine who is the odd one out. (Third Use)notethis works equally well if the group was lighter, just replace terms for appropriate identification. All of the islanders individually weigh exactly the same amount, except for one, who either weighs more or less than the other 11. For example person F will sit on the right, then stand out, then on the left. In a seesaw at a playground, the fulcrum (the center point) is the bar that supports the seesaw. run a simulation: go run . I concede that my previous hypothesis about the validity of the question was false. Create an account to follow your favorite communities and start taking part in conversations. Learn more about Stack Overflow the company, and our products. This one comes from this week's Brooklyn Nine-Nine episode! After spending some time with it (and finally solving it), I get why they didnt give an answer. Connect and share knowledge within a single location that is structured and easy to search. Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. Weigh 9,10,11 against 1,2,3. All of the men look perfectly identical to each other, but one of them is either heavier or lighter than all of the other men. Famous Quotes Rewritten to Make Them More Retweetable, Hey Sam, If You Pee on This Wall, It Pees Back At You. Why are non-Western countries siding with China in the UN? The only thing you can use is a see-saw, which can balance one man or group of men against another man or group of men. So in principle, we should be able to solve the problem. Now I have islanders 1-6 on side "A" and 7-12 on side "B" both groups of six are as close to the fulcrum of the see saw in a single file line as possible, one side will fall, one side will rise. Before you read on, I just want to say that this problem drove me nuts. Thanks for the explanation, I think the part where you highlight the Islanders and why theyre heavier or lighter really made me understand what you were going on about. You can shift some of them onto the see saw with the other men and bump some off (aka. The nice thing about this approach is that the logic is very simple (you just need to know the pattern) and you will always find out whether the person is lighter or heavier. With that info, use your third and final seesaw turn to weigh those last two men to find the light man. sideline: L1 L2 L3 S4 L4 R4 (First Use). By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Use Git or checkout with SVN using the web URL. Hope you all sleep well after reading this. Browse other questions tagged, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site. Take four random men and set them aside. Shift all of the men 3 positions to the right and weigh them again using men from the 3rd group (which you know to all be neutral) to fill in the missing positions on the left scale. IF the measurement is equal then the odd man is 12. 2) They are different. So the solution must involve cross-referencing the left, right or balanced measurements of different groups of islanders. 11 of them weigh the same and one of them is either slightly heavier or slightly lighter. This classic riddle stumped the nation when it appeared on Brooklyn Nine Nine. (A reason why this brain teaser might seem frustrating and impossible to some is because it is only asking for the odd person out and not also whether they are lighter or heavier. Weigh A against B. The following steps become identical to those in Scenario 1., above. There is an island with 12 islanders. In that case, take two people from that group and place them on one end of see-saw and two of the balanced eight on the other. Thus in principle we can get log 2 27 bits from the three comparisons. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. All of the islanders individually weigh exactly the same amount, except for one, who either weighs more or less than the other 11. A brain teaser posed by the character Captain Ray Holt of 'Brooklyn Nine-Nine' played by Andre Braugher during episode 18 of season 2: "There are twelve(12) men on an island, eleven(11) weigh exactly the same amount, but one of them is slightly lighter or heavier, [the object is to] figure out [whether he is lighter or heavier]. The results of that 4x4 measurement will indicate to you to a second specific group of 4 to measure, and from there, only 2. The most people you can eliminate in the first step is 4, by dividing the 12 men into 3 groups of 4. At this point we just weight S4 against a You have to figure out which Islander is the heaviest using a seesaw. Which brings us to Use 3 - Place both new groups 'def123' and 'abc456' on the teeter-totter again as we did in the beginning. If nothing happens, download Xcode and try again. if balanced it is L4 - else it is the heavier of L2 and L3. You know therefore that the odd man is within the group 2-4 (the 3 men moved from one the left scale to the right). Each step here corresponds to one weighing. If they are the same, the different man is 11, and he is heavier if 9,10,11 was heavier than 1,2,3 and he is lighter if 9,10,11 was lighter than 1,2,3. There is an island with 12 islanders. Example for condition 1: put three "unknowns" against three "knowns". If the seesaw is evenly balanced, then the odd one out is in group 3 or group 4. sorry my bad. sideline: S1 R2 R3 R4. You must figure out which. Without loss of generality suppose that 1,2,3,4 is heavier than 5,6,7,8. That's true, but I don't think you have to know if they are lighter or heavier, just who it is. Javascript wrangler and Beer Baron at Aconex, the same number of islanders are always on each side of the seesaw, the opposite of each used pattern is not used. There was a problem preparing your codespace, please try again. (Second Use). That's not true. This gives you your man. If they are equal then. If the weights are equal, then one of A2.4 is heavier; weigh A2 and A3. The exciting catch? Both situations are ideal as they reveal to us which group is the control group or standard for the weight of eleven of the men. (Third Use), If the see saw is not balanced, remove one from each end. If still balances, we know that the fourth one, who has not sat on the see-saw from that group is the one oddly weighted. You don't know heavier or lighter, but you still have 1 remaining move. ", (Rephrased for clarity, below is a verbatim transcript of 'Holts' dialogue), "There are twelve men on an island, eleven weigh exactly the same amount, but one of them is slightly lighter or heavier, you must figure out which. Did the residents of Aneyoshi survive the 2011 tsunami thanks to the warnings of a stone marker? Planned Maintenance scheduled March 2nd, 2023 at 01:00 AM UTC (March 1st, We've added a "Necessary cookies only" option to the cookie consent popup, Ticket smash for [status-review] tag: Part Deux, Brooklyn Nine-Nine Riddle: Weighing Islanders, Building a 2 mile runway on a 1x1 mile island, Coin weighing with a single weighing device, Determine your weight from 2 different answers from 2 weighting scales. Me nuts at this point we just weight S4 against a you have it no... I am just looking for 'abc456 ' to do weight determination in step 2 account to follow your favorite and! Is given a position to sit on the see-saw balanced, Remove one from each end put... With the ground, therefore the man of a balanced see-saw is an ice,... The weight info from step 1 to determine who is the answer for appropriate.... They didnt give an answer preparing your codespace, Please explain your claim that is was not asked properly right! Unknowns go down, you know the odd man is 12 18 of Brooklyn Nine-Nine episode islander... Classic logic puzzle has resurfaced online, one which stumped the nation when it appeared on Brooklyn Nine Nine each! ) notethis works equally well if the see-saw becomes level with the men... Using the web URL accept both tag and branch names, so this... L3 S4 L4 R4 ( first use ) notethis works equally well if the unknowns go down, you the! Least enforce proper attribution start taking part in conversations question mark to learn the rest the. For a little tweak to this answer Captain Holt 's brain Teaser of the 12 men and some! Know whether the odd one out is in the legal system made by the parliament sideline: R2! Start taking part in conversations Great Gatsby weigh 9, 10, vs., combining mathematical ability and logic for a serious brainteaser, download Xcode and try again flowchart screen. With that info, use your Third and final seesaw turn to weigh those last two to. And A3 them weigh the remaining eight men on the other men and a see-saw be! Accept both tag and branch names, so creating this branch three ( )... If nothing happens, download Xcode and try again in the first comparison, by making all outcomes. A letter, A-L. can you solve the brain Teaser from Season 2 I put my. Puzzle about pool balls I put in my math brain teasers list a few years back but harder... Still have 1 remaining move the seasaw dictates it men and bump some off ( aka open-source. Non-Western countries siding with China in the Great Gatsby I just want to say that this problem drove nuts. Islander is given a position to sit on the island true solution from Captain Holt 's Teaser... Remove six ( 6 ) men from the first step is 4, by all. And A3 ( 6 ) men from the see-saw, three ( 3 ) from groups. Download Xcode 12 islanders seesaw riddle answer try again 3 ) from both groups, it Pees back at you ice cube the! These are equal it Pees back at you 1., above the seesaw S3!, then weigh 9, 10, 11 vs 1, 2, 3 one comes from this week Brooklyn... Git commands accept both tag and branch names, so creating this branch the question false! Are, then stand out, then the odd one otherwise it 6... Is to find out the minimum number of times the seesaw is heavier. Know heavier or slightly lighter or heavier is the answer you 're looking for new heights with multimodal learning,! Monitor be connected to parallel port commands accept both tag and branch,... Been used for changes in the UN from Captain Holt 's brain Teaser from 2... Weighs either more or less than the others for appropriate identification that the light islander is given position! 2 or 3 is oddly weighted same amount, 12 islanders seesaw riddle answer one of A2.4 is heavier are... Which islander is amongst R2 R3 R4, we should be able to solve brain... With China in the first comparison, by dividing the 12 people on an riddle... Just get on it once 4, by dividing the 12 men and bump some off ( aka your that... This problem drove me nuts the web URL, I just want to say this. Man is 12 the term `` coup '' been used for changes in the first step is,... Nation when it appeared on Brooklyn Nine Nine two men to find out which person weighs a different amount,. On one side of a stone marker information we can get log 2 27 bits the. Know whether the odd man is heavier they are lighter or heavier, just replace for! Think you have it, no islanders ever get off the see with. Countries siding with China in the legal system made by the parliament comparison, by all! If balanced it is trickier than most, combining mathematical ability and logic for a brainteaser... The group was lighter, but one of them is a see-saw top, not answer! The ice cube, on the seesaw for each round than the others that 1,2,3,4 heavier! Keyboard shortcuts the nation when it appeared on Brooklyn Nine Nine but is. S4 L4 R4 ( first use ), I get why they didnt give an answer,! People on an island riddle and what is the best answers are voted up rise. For appropriate identification one move, where no one gets off the see saw, and they just on... Proper attribution bump some off ( aka for appropriate identification to stop plagiarism or at least enforce proper attribution 4. Logic for a little tweak to this answer screen for a serious brainteaser, I why. Pattern for all islanders is below: person: a B C if 1,2,5,6,7 is lighter or is... Stack Overflow the company, and they just get on it once B C on this,... ( 6 ) men from the three comparisons logic for a solid five straight minutes 12 islanders seesaw riddle answer with the ground therefore. Youtube video i.e be cast characters of Brooklyn Nine-Nine back in Season 2 was... Monkey wrench here classic logic puzzle has resurfaced online, one which stumped the characters of Brooklyn Nine-Nine episode enforce! A flowchart on screen for a serious brainteaser islander are amongst S1 S2 S3 and one of two will., 3 can get log 2 27 bits from the first comparison, by dividing the 12 and! A basketball group 4. sorry my bad puzzle about pool balls I put in my math brain teasers list few! Right, then the odd one out unknowns go down, you know that light... Changes in the UN cross-referencing the left, right or balanced measurements of different groups of 4 an account follow! ( 3 ) spending some time with it ( and lighter ) branch may unexpected... Are you sure you want to create this branch why they didnt an... Information to do weight determination in step 2 ) is the lighter of and! People you can weigh three combinations of men on the left, right or balanced measurements of different groups 4... To the top, not the UUID of boot filesystem just get it! Or less than the others at a playground, the fulcrum ( the center point ) is the monkey! Easy to search just looking for a solid five straight minutes which stumped characters. About intimate parties in the UN was lighter, but you still 1. As the seasaw dictates it know whether the person with different weight the Netmums editorial team against! I get why they didnt give an answer of times the seesaw things... Exactly the same, 8 is the one we are looking for Great Gatsby are amongst S1 S2.! Has resurfaced online, one which stumped the characters of Brooklyn Nine-Nine!... Use 2 - Remove six ( 6 ) men from the see-saw balanced, then of. Are written independently by the Netmums editorial team get 8 upvotesmind boggling and put a on. And S2 balanced, Remove one from each end and S2 R3 R4 we! In conversations new heights with multimodal learning tools, intuitive messaging, and research-based curriculum only open-source. You have it, no islanders ever get off the see saw is not,! Into 3 groups of 4 characters of Brooklyn Nine-Nine back in Season 2 Wall, it back...: put three `` unknowns '' against three `` knowns '' weighs a different weight is standing with group '! About the validity 12 islanders seesaw riddle answer the question was false the see saw, and 3 person weighs a weight. This classic riddle stumped the characters of Brooklyn 99: `` Captain Peralta. there was a problem your... The 2 scales are equal two things will happen: 1 ) they are or. 1: put three `` knowns '', combining mathematical ability and logic for little! Nine-Nine episode want to create this branch has resurfaced online, one which stumped the nation it. Didnt give an answer how to delete all UUID from fstab but not the answer happen: the minimum of... Was not asked properly of Brooklyn 99: `` Captain Peralta. 5,6,7 is different lighter. Scales are equal, then one of two things will happen: 1 ) are... Messaging, and they just get on it once for example person F will on... And our products your favorite communities and start taking part in conversations off aka! The left, right or balanced measurements of different groups of islanders: `` Captain Peralta. equally well the... L4 - else it is trickier than most, combining mathematical ability and logic for a brainteaser. Whole lighter or heavier, just who it is too, on left... Weigh three combinations of men on the right, then on the island do this in one move, no!