Mathematics Stack Exchange
Mathematics Stack Exchange

Questions tagged [puzzle]

For questions about the mathematical principles behind puzzle, games, riddles, or their possible solutions. Questions that are not strictly mathematical in nature should be asked on Puzzling Stack Exchange.

Many puzzles, games, and riddles are based on mathematical concepts. This tag is for questions that ask about the mathematics behind a puzzle, game, or riddle, or about the solutions to mathematical puzzles.

If you already know the answer to the puzzle you are posting, you might consider posting your question on Puzzling Stack Exchange, instead. If you do end up posting your question on Mathematics Stack Exchange (MSE), please read the following meta posts on these kinds of questions before asking your question:

If you do end up posting on MSE, please make it clear in your question that you are "puzzling" the community and that you will be answer the question yourself if no one in the community posts your desired solution.

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Number of distinct points at which runners meet.

Two persons are running on a circular track either in the same direction or in the opposite direction, indefinitely. The speed of both of them is given, say $u$ and $v$. Now, how do I find out the the number of distinct points at which they will…
n0nChun
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What is the best way to set up a table for a puzzle like this

I need to rearrange this to form a logical sequence. One way is to just to trial and error, however since there are 5*4*3 ways this can rearrange, that is not efficient. Is there a way to number the elements so I can see a pattern clearly?
stackdsewew
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Nice explanation for simple puzzle

There is a simple game with coins that goes as follows. You have $x$ coins and two players who take turns. Each player can either remove one or two coins. The winner is the person who removes the last coin(s). A little experimentation will show that…
user66307
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What's the solution to this puzzle?

I saw this on Instagram with no solution and was wondering what the answer is. I got $33$. $$1+4=5$$ $$2+5=12$$ $$3+6=21$$ $$8+11=?$$
nullByteMe
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Clock Problem of logic

There is an analog clock that runs 90% of the normal speed of a clock.This clock will show the correct time exactly two times a day. Prove the following.
Moon
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$3$ children riddle, compute the ages based on information given

A man has $3$ children such that their ages add up to some number $x$, and whose ages multiply to some number $y$, such that $xy = 756$. What are the ages of the $3$ children? Letting the ages be $a$, $b$, and $c$ of the three children, what we…
David
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Logic puzzle, numbers on the back of head

Ok, I found this puzzle and I can't figure out the answer: Two people, Albert and Bernard have a natural number {0,1,2,3 ...} on the back of their heads. Rules: They can't see their own number Albert stands in the back of Bernard, so he can see…
user295373
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How many balls does he put into each green bag?

This is a homework problem my son brought home -- 5th grade. Raul has 56 bouncy balls. He puts three times as many balls into red gift bags as he puts into green gift bags. If he puts the same number of balls into each bag, how many balls…
rrauenza
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Crossing the River Story Problem

A group of adults and children go on a camping trip. On the first day, they come to a river too deep to wade across. They find a small canoe which can carry either one adult or up to two children at a time. The canoe cannot hold one adult and one…
Ben
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Math riddle - Forehead numbers

Three players, Annie, Billy and Katie, each have a natural number written on their foreheads. Each player can only see the foreheads of the other two. The following two things are common knowledge among the players: One of the numbers is the sum…
Jorj
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A Solution to the Classic "12 Marbles, find the one of different weight" Brainteaser

The classic problem goes like this: You are given a set of scales and 12 marbles. The scales are of the old balance variety. That is, a small dish hangs from each end of a rod that is balanced in the middle. The device enables you to conclude…
RPz
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on which floor does she lives?

A woman lives in a 36 floor building. There is a lift in that building. When she leaves her aprtment and goes to lift,there are 3 times chances lift will take her up than take her down(3:1,up:down)..On which floor she lives? Kindly help with the…
user248777
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How do you prove that a certain series of moves will guarantee a total win in 'eating apple' math puzzle?

Today our professor presented us with a puzzle of interest called The 'eating apple' problem (I have no idea what is it called formally though). The rules are There are three compartments, containing 3, 5, and 7 apples respectively. Two players,…
Kang Min Yoo
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Is the puzzle logically (or in some other way) correct?

There are 30 metereologists working in their laboratory making predictions about the weather for the next day. They say either "Tomorrow will be sunny" or "Tomorrow will be cloudy". One of the metereologists is always right. Others might make a…
Lex
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What question to ask to find right path

Suppose a certain country is inhabited by truth teller and liars, who only respond to yes or no questions. A tourist comes to a fork in the road where one branch leads to the capital, and the other does not. There is a native standing at the fork. …
user232751
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