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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The Impossible puzzle ("Now I know your product")

I am trying to figure out this impossible problem by Martin Gardener and still havent found a suitable solution or link to it Two mathematicians S and P are discussing two unknown integers, both greater than 1. S knows only the sum of the …
Vrashabh Irde
  • 453
12
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3 answers

A polyomino puzzle

Is there a polyomino such that it can be glued to an I-shaped pentomino and to a X-shaped pentomino to obtain the same polyomino? Or is there simple proof for non-existence of such polyomino? [Edit: See "I-shaped" and "X/(+)-shaped" pentominos…
bleh
  • 368
12
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4 answers

Can the product $AB$ be computed using only $+, -,$ and reciprocal operators?

Can the product of $A, B$ be computed using only $+, -,$ and reciprocal operators using a calculator? You can use calculator's memory function (multiply and divide are broken though). Additional: I should have mentioned earlier, in addition to the 3…
Prateek
  • 293
10
votes
1 answer

Determining the favored penny on a chessboard

Let's suppose there is a chessboard (with 64 squares), and there is a penny on each square. Each of the pennies has a side (head or tails) facing up, chosen at random. I look at the board and choose my favorite penny. I then tell my two…
Peter Olson
  • 2,253
9
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1 answer

Is this mechanical puzzle (Loony loop) solvable?

"The aim of this puzzle is to free the tied cord from the figure-eight metal loop, without breaking or untying the cord."
Mitja
  • 193
9
votes
2 answers

Six ducks in a pond

This puzzle has got me stumped. $6$ ducks are swimming on a pond radius $5$. Show that at any moment there are two ducks a distance at most $5$ apart.
marshall
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9
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4 answers

Putnam 1990: Problem A-4

I was told this lovely puzzle recently which I thought people here might enjoy. Consider a paper punch that can be centered at any point of the plane and that, when operated, removes from the plane precisely those points whose distance from…
user66151
9
votes
3 answers

How Strong is an Egg?

You have two identical eggs. Standing in front of a 100 floor building, you wonder what is the maximum number of floors from which the egg can be dropped without breaking it. What is the minimum number of tries needed to find out the solution?
Jaguar
  • 485
9
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1 answer

Place each number from 1 through 10 in a box...

The puzzle is: Place each number from 1 through 10 in a box. Each box must contain a number that is the difference of two boxes above it, if there are two above it. The ten boxes are positioned in an inverted triangle with side 4. My question is:…
sds
  • 4,533
9
votes
5 answers

Trip around the Earth

You are standing at an airport (that lies somewhere) on equator (of the earth) and have an unlimited number of identical aircrafts (same model, make and fuel capacity etc.) to make a complete trip of equator. Each of the aircraft has the fuel…
Ravi Gupta
  • 613
8
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3 answers

No of comparisons to find 2nd smallest number?

you have 32 numbers. What is the least number of comparison needed to find the 2nd smallest out of them. As per me it 61 comparsisons are required. Compare first two number in list. Assign largest and second largest to them based on comparison. Now…
user3198603
  • 183
8
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2 answers

Fun math puzzles for kids

I'm trying to find fun puzzles for younger people (7 years of age and up). I've browsed the internet, searched through math books etc but haven't really found a stellar puzzle. I realize that perhaps math does not lend itself to puzzles that well,…
VonSchnauzer
  • 183
8
votes
2 answers

Bit placement puzzle

Consider a binary vector of length $n$ that is initially all zeros. You choose a bit of the vector and set it to $1$. Now a process starts that sets the bit that is the greatest distance from any $1$ bit to $1$ (or an arbitrary choice of furthest…
user66307
8
votes
1 answer

Shop Chocolates puzzle

I was trying to solve a puzzle but was not able to find any solutions if any one knows the solutions please, share. "You own a shop of chocolates. You want to give exact number of chocolates (say for orders up to 1000 chocolates) to customers…
Neo-coder
  • 181
8
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2 answers

Least amount of steps to get over 1000

I am wanting to type out 1000 characters onto a message, I start off with one character and I have that character in my clipboard. I then paste it to get two characters. From here I can either select all, copy, navigate to the end of message and…
VikeStep
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