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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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Puzzle about six travellers going through bridge above canyon with an oil lamp

There is a dark night and there is a very old bridge above a canyon. The bridge is very weak and only 2 men can stand on it at the same time. Also they need an oil lamp to see holes in the bridge to avoid falling into the canyon. Six man try to go…
Yoda
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Apparently Simple Puzzle

So a picture appeared on FB asking for the answer to the picture below, to which many people responded "14". Everywhere I looked, people answered 14. However, I stood out because I was the only one who said that the answer is 11.25. The problem…
GelatinFox
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Dividing a circular field in 4 equal parts by putting 3 equal straight fences

In the book of Math Puzzles by Martin Gardner, an interesting way to divide a circular field in four equal parts by putting 3 equal curved (made up of circular arcs) fences has been discussed. The question here is: can one do the same by putting 3…
Z Ahmed
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Three bucket water puzzle

You have three buckets, two big buckets holding 8 litres of water each and one small empty bucket that can hold 3 litres of water. How will you split the 16 litres of water to four people evenly? Each person has a container but once water is…
sundar
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Limitations on orientations of a character on the surfaces of a cube

When looking at a cube you see either two surfaces across an edge or three surfaces around an apex. Is it possible to arrange a non-symmetrical character (e.g."R") at 0,90,180 or 270 degrees rotation on each surface of a cube such that no two…
user56748
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Finding an equation for a math puzzle

There is a question for which I can't find an equation to solve it: After $m$ couples leave a party, the total number of people drops by 20%, and the number of men drops by 12.5%. Which case is greater: One-third of the men before the couples…
Ahmad
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How many positive integers from 1-1000 have 5 divisors?

How many positive integers from $1-1000$ have $5$ divisors? Any answers would be greatly appreciated. If you have any questions, I will edit for clarification.
Jmaxmanblue
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Counting siblings problem

A person has told us that at least half of his or her siblings have exactly three sisters and not more than half of his or her siblings have at least four brothers. How many arrangements of brothers and sisters matching this description are…
Alternatic
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Puzzle: Dropping balls along the way

A man has some balls in his pocket. Let the number of balls in his pocket be $n$.(Consider $n$ as an integer. If any decimal value occurs, consider its floor value. For example, if $n$ = 2.6 then take it as 2). For every mile that he runs, he is…
Vishnu Vivek
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Cut the rope puzzle

This question was asked to me in an interview, I still cannot think of its solution. Can anyone help? Following is the question: Given an infinite number of ropes of length $R$, you have to calculate the minimum number of cuts required to make…
vaibhav
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Formal logic and recreational puzzles

I am a self-learner who became interested in formal logic after stumbling upon some puzzles, like those by Raymond Smullyan in To Mock a Mockingbird. I am interested in starting with an intro book like this (though I'm open to more suggestions, just…
Velok
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Prove or disprove $p(|T|)\neq 0\longrightarrow \exists v\in V_c:R(v)\neq 0$

I came along this one problem, but I don't know from where to approach it; the problems states: You are on a point in a 2D grid, and your only valid moves are up, down, left and right, 1 unit a a time. There also are cylinders, in the middle of…
Garmekain
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The old church (from Littlewood's Miscellany)

I’m in the part of the human race that doesn’t ‘get’ the following paragraph. If you are in the other part, please a) wipe that smirk off your face, b) explain what I’m missing (ideally, preceded by a hint). Thanks! The old church. Old lady: …
user34099
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How many lines are needed on the plane to get all angles from $1$ to $359$ degrees?

I am trying to solve following problem: How many lines are needed on the plane to get all angles from $1$ to $359$ degrees? We can move lines in parallel. I am thinking that since moving in parallel doesn't change angles we can put them intersecting…
Ashot
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Mathematical puzzle on the coordinate planes.

Recently, I come across this quite interesting mathematical puzzle: Consider the ten points $(0,0)$, $(1,2)$, $(3,3)$, $(4,1)$ and $A, B, C, D, E, F$ on the coordinate plane. It is known that if any five points are chosen from these ten points,…
Mc Cheng
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