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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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How to find the missing number

How to find the missing number $\{14,36,25,25\},\{20,50,20,10\},\{36,54,7,?\}$ answer was $3$ , but I dont understand why? well these four sets of numbers were kept in four seperate circular plate and the plates were divided in four part.
Myshkin
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How to solve a prime number-logic problem

I am sitting with two other people who are wearing hats with the prime numbers 5 and 11. My hat has a prime number also, but I don't know what it is, nor do each of them know their numbers. It is also known that our three numbers represent side…
Ken Bannister
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Fox and rabbit on circular path

Thank you for your solutions "Can fox catch rabbit" (There are five holes in a line. One of them is occupied by a rabbit. Each night, the rabbit moves to a neighboring hole, either to the left or to the right. Each morning, a fox get to inspect a…
deepblue
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Puzzle - scoring in a contest

At the finals of the "Gaana Sunao" contest, which was conducted all over India, five contestants - C1, C2, C3, C4 and C5 - participated. Before the announcement of the results, six mischievous persons - Azad, Bose, Chand, Dev, Ehsaan and Fardeen -…
Fin27
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Largest three digit number comprising of only 1's and 0's that when divided by 23 gives a remainder of 18

So I had a Year 11/12 Maths Competition today and one of the last questions on the competition paper was this: "A certain number is comprised of only 1's and 0's. When divided by 23 it has a remainder of 18. What is the highest amount of "1's" in a…
VikeStep
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$A\times BC=DEF, K\times GH=DEF$

If $A,B,C,D,E,F,G,H,K$ are distinct single digit natural numbers and if $$A\times BC=DEF, K \times GH=DEF$$ where $BC,DEF$ are two and three-digit number. Find these digits. Is the answer unique?
MathDona
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Ten natural numbers such that the sums of each choice of nine of them are $82, 83, 84, 85, 87, 89, 90, 91, 92$

In a Whats App group the following puzzle was asked Ten (not necessarily different) natural number are such that if all but one of them is added, the possible results (depending on which one is omitted) are 82, 83, 84, 85, 87, 89, 90, 91,…
Z Ahmed
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explanation for martin gardner's ultimate bible code

in one of his texts, martin gardner presents the ultimate bible code: Bible. "Select any of the 10 words in the first verse: In the beginning God created the heaven and the Earth'" "Count the number of letters in the chosen word and call this…
Humberto José Bortolossi
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What is the equation for the least amount of clues needed for a sudoku puzzle related to size?

What is the least amount of hints a sudoku puzzle needs to be solved related to size $n*n$. The classic sudoku puzzle is a $9*9$ grid that is divided into rows, columns and $9$ $3*3$ squares called a nonet, where:\ Each column must contain the…
Katelyn Terhune
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Proof of shortest path to move a block from top-left to bottom-right in an $n\times n$ sliding puzzle

Consider a 3x3 matrix: X O O O O O O O Here the X is to move to the empty square by shuffling the board as a slide puzzle. I have failed to find a formal proof of what the fewest number of steps is, or what this puzzle is called.…
user1603472
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puzzle/equation with proportionality

We have three pumps filling a tank: The first one fills the whole tank in a particular time, the second one is twice as fast as the first one, and the third one is three time as fast. All the pumps together can fill the tank in two minutes. How long…
TestGuest
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Is there a general solution for an equation such as N - M = 2021 where N is four digits and M is three digits of N

The question is, given N of four digts and M which is based on any three digits of N (but in the same order as those of N) and the difference between N and M is 2021, what is the original number N? The way I have worked this out is to take all four…
Richard Hammond
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Minimize final marks of the student as per the marking scheme provided in the question

Question:- The scores given by three of the four professors are 45, 49, 52 for each of 2 students Alex and Dan. What is the minimum possible final score of any student ? My approach:- Assuming the fourth score to be $x$. Now $x$ has to be less than…
Fin27
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Logic puzzle to prove which relative is male or female?

C, D, E, F, G, H, and I are the father, mother, aunt, brother, sister, wife and daughter of J, but you do not know which is which. But you know that: E and F are the same gender. C and D are of different genders. H was born before C F is not the…
Contango
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Integers from 2-11 in a irregular grid of 10 squares

While reading a past paper, I found this problem: Write the positive integers 2-11 (2 and 11 included) into ten little squares shown in the picture below, so that each square has one number and the numbers in these squares are all different. If the…
Tyrcnex
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