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.

3301 questions
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Logic Puzzle with Eight Clues

I am not sure where to start to solve this problem: Smith, Jones, and Rodriguez are the engineer, brakeman, and fireman on a train, not necessarily in that order. Riding on the train are three passengers with the same last names as the crewmembers,…
Jorge Reis
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Coin toss puzzle with 1 biased and 2 unbiased coins

Three coins are given: one two-head coin and two fair coins. You randomly choose a coin and the first three tosses give heads. What is the probability that 4-th toss is a head. I have two solutions that give different results. Please help me to find…
Kim
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Math puzzle I have been stuck on

Have had this math puzzle that I have been unable to solve for a while. Each leter is a number between 1-9. No letter uses the same number twice (aka if B is 3 D can't be 3 also). The ? mark represents an unknown letter (as in it could be any…
bobAlex
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2 answers

Searching specific numbers based on clues

"Find x for 0≤x≤100,000." My clues are as following. I'm not sure whether there are multiple answers or that only one 'x' remains based on these clues: This number isn’t between 20,000 and 40,000 or 60,000 and 80,000. This number is divisible by…
Nick
  • 31
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5 answers

A peasant and his cows

A peasant owns $2n+1$ cows. When he separates a cow from the rest of the herd, he can split the $2n$ remaining ones into two groups of $n$ cows such that the sum of weights of each group are equal. Prove that the cows all have the same…
Gabriel Romon
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empty boxes puzzle

The problem is N large empty boxes (assume they are of type:1) are initially placed on a table. An unknown number of boxes (type:1) are selected and in each of them K smaller boxes (type:2) are placed. Again an unknown number of type:2 boxes are…
user3263245
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Two plants, a rose and a jasmine.....

Q1: Two plants, a rose and a jasmine, grow up and around a cylindrical tree trunk. They start from the same point at the foot of the tree, but the rose goes clockwise and the jasmine counterclockwise around the trunk. When the two plants meet at the…
Harry
  • 81
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determine the number thought of

Ten people are seated around a circular table. Each of the ten people thinks of a number and whispers it to his/her two neighbours. Then these ten people announce the average of the two numbers they heard each such that we have 1, 2, 3, 4, 5, 6,7,…
Epa
  • 259
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2 answers

Interview question - numbered tiles

Ok, this interview question interested me and I would love to see an explanation! There are some tiles: 1, 1, 2, 2, 3, 3 They must be placed in a straight line, such that there is one tile between the 1s, two tiles between the 2s and three tiles…
Mark
  • 123
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Seating Arrangement puzzle.

Not sure if its a correct place to post these kind of questions. Eight persons-P,S,Q,R,U,B,J and C are sitting in a field in a circle. Three are facing opposite side and other five are facing the centre. S is sitting to the third right of B. R is…
Arvind
  • 146
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Mathematics riddle

The question is as follows: You are taking part in a treasure hunt, where the directions to finding the treasure are given using cryptic clues. You start at a cross-roads, with roads heading out east, west, north, and south. You receive the…
Tania
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2 answers

Superqueens on a chessboard

The superqueen is a chess piece that can move not only like a queen, but also like a knight. What is the maximal number of superqueens on an $8 \times 8$ chessboard such that no one can capture any other? Additional information: Of course at most…
Daniel Soltész
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A Different Type of Knights and Knaves

You arrive on the island with knights and knaves. Like usual, knights can only tell the truth and knaves can only tell lies. You wish to determine the truth of a rumor that one of the inhabitants has recently proved Goldbach’s Conjecture. What…
UserX
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2 answers

ABCDE + BCDE + CDE + DE + E = AAAAA

Today I came through this question when one of my friends asked. I don't know if this math.stackexchange community is the right place. I am new but active on other SO communities. Take me easy if this is not the right place to ask the question.…
Raghavendra
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Math riddle (ambiguous minutes/hours dials) - can you find my mistake?

I was given the following riddle: You are given a clock which has identical dials for the hours and minutes. How many times a day you can't tell the time? (i.e. the dials are indistinguishable)? I'm not asking for a solution, but rather for help…
E C
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