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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.

3301 questions
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A logic puzzle involving a balance.

Possible Duplicate: Optimal algorithm for finding the odd spheres You have 12 balls and you know that they all weigh the same except for 1 which is heavier or lighter than all the others (you don't know which though). How can you make sure you…
Hautdesert
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Palindromes on a digital clock

A palindrome is a number that reads the same forwards and backwards,such as $55$ and $12321$. How many times in a $24$-hour period of time on a digital clock does the number reveal a palindrome?
David
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Riddle about 3 men competing and never tying

Mr. A, B, C decided compete in athletics against each other. They competed in few disciplines. Winner got x points, second y points, last z points: x>y>z. x,y,z are integers. There were no draws(ties) in any discipline. Mr. A scored 22 points, Mr. B…
Yoda
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Find two numbers whose ratio is $1/2$ using each non zero digit.

So in this question i first figured out that the numerator must be greater than $5000$ so that there are $4$ digits on the numerator and $5$ digits on the denominator. And then after a few random guesses: $$a=9273$$ $$b=18546$$ satisfied the…
rnjai
  • 1,774
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The Magic Hat Puzzle ...Vinnie's number is always one above or below Tommy's...

Imagine there is a hat sitting on the table. And there are two contestants. You, Tommy, will be one of the contestants, and we'll call the other one Vinnie. You reach into the hat, and pull out a number. Then, Vinnie does the same. Now, the reason…
math wannabe
  • 696
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Measuring water puzzle

Given two unmarked jugs, one which holds 7 liters, and another which holds 11 liters, an unlimited supply of water, and no need to conserve, how do you measure exactly 6 liters? I would also like to know whether there is a single solution , many…
user108097
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Number Of races needed?

25 horses, 5 race tracks; we need to choose the top 3 horses. What is the minimum number of races you need? I have thinking deeply and figure out this: First race all 25 horses in groups of 5 to figure out the top 3 in each group (which will leave…
rohit
  • 387
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Escalators visible steps question.

A person always walk down on a moving escalator to save his time. He takes 50 steps while he goes down. One day due to power failure of 10 sec, he took 9 seconds more to get down on than his usual time. What is the number of visible steps of the…
Sherlock Watson
  • 623
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How long does it take to fill up the tank?

It's a really simple question yet I cannot come up with the answer for it, we have a tank of water, and we have $4$ people if they try to fill the tank separately it will take $1$st person $60$ minutes to fill $2$nd person $45$ minutes to…
Sarkar
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Lights brain teaser

$N$ lights are off. There are $N$ switches. Switch $i$ controls light $i$, and it may control other lights in addition to light $i$. The switches and lights are interlocked (if switch $i$ can turn on light $j$, switch $j$ can also turn on light…
vyjtkbyykyhuk
  • 183
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Maximum value of products the person can buy

D-bay, an online clothes and fashion store, is giving a 20% cashback on purchases worth €1000 or above made on its website. (i.e. when you purchase something worth, say, €3000, your account will be credited back with an amount of €600). If Alex…
Fin27
  • 958
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Lufia II: Puzzle - What kind of knowledge helps to create this kind of puzzle?

In the super nintendo game "Lufia II", game developers included multiple little block puzzles throughout the game. However, one in particular is considered a standout: This is a kind of sliding puzzle similar to the "15 puzzle"…
Pan Pops
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Knights $3\times 3$ riddle

There are $4$ knights on a $3\times 3$ chessboard, $2$ white, and $2$ black as depicted in the figure. Each player in his turn moves the knight (with the usual knight move as in a chess game) to an available spot on the board (no captures are…
anon1990
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Finding all integer solutions to $A\times B\times C = A! + B!+ C!$ with $0\leq A, B, C\leq 9$ without trying every combination?

Let $A$, $B$, $C$ be integers such that $0 \le A, B, C \le 9$. Find all the solutions for $$A\times B\times C = A! + B!+ C!$$ I have tried some values for $A$, $B$, and $C$ and found a solution: $A=4$, $B=3$, $C=3$. Is there a way to solve this…
lorenzoayub
  • 43
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Find the poisoned pie

You are a pie maker and you are holding a fair to display your pies. You have 1000 pies. You have 10 workers to help you. The fair is in two hours. Unfortunately you discover that a rival pie maker has poisoned one of your pies with a form of…
Alan
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