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
0
votes
3 answers

M is nice if it is possible to make it all + by a set of operation, each consisting of changing the sign of one row or the sign of one column.

Let $M$ be an $n\times n$ matrix whose entries are $+$ and $-$. Call $M$ nice if it is possible to make it all $+$ by a set of operation, each consisting of changing the sign of one row or the sign of one column. Design a simple and efficient…
yyyyt
  • 3
0
votes
1 answer

Does this question provide enough information to answer?

Lewis Carroll posed the following problem: Two travelers spent from 2 o’clock until 9 walking along a level road up a hill and home again; their pace on the level being $x$ miles per hour, uphill $y$ mph, and downhill $2y$ mph. Find the distance…
nahsor0
  • 3
0
votes
0 answers

How many lockers are open?

Q.> A high school has a strange principal. On the first day, he has his students perform an odd opening day ceremony: There are 1000 lockers and 1000 students in the school. The principal asks the 1st student to go to every locker and open it. Then…
Subham Sen
  • 3
0
votes
1 answer

Puzzle on the minimum number of distinct people

There are 12 photos and there are 3 women in each of the 12 photos, left, middle and right. In each photo, the woman in the middle is the mother of the one on the right, and the woman in the middle and the woman on the left are sisters. If I tell…
user1780424
  • 133
0
votes
2 answers

Puzzle relation with geomtry

An army $40$ km long is moving at constant speed. A horseman takes a message from the rear end of the army to the general in the front end of the army and returns back to the rear end of the army (moving with constant speed). During this time, the…
1ENİGMA1
  • 1,185
  • 8
  • 19
0
votes
0 answers

Select the suitable figure from the four alternatives that would complete the square matrix.

Tried to find different clues from the image such as counting sides, shapes, sizes etc. but no solid clue found. I think the answer is 'D', requesting your opinions.
Dinesh Potluru
  • 235
0
votes
1 answer

What is the logic behind this puzzle's answer?

Keep a number between $1$ and $60$, including $1$ and $60$. The aim is to find kept the number. $1,3,5,7,9,\\ 11,13,15,17,19,\\ 21,23,25,27,29,\\ 31,33,35,37,39,\\ 41,43,45,47,49,\\ 51,53,55,57,59\tag{box 1}$ $2,3,6,7,10…
1ENİGMA1
  • 1,185
  • 8
  • 19
0
votes
4 answers

Filling pool with 3 hoses puzzle!

I'm stumped on a math puzzle and I can't find an answer to it anywhere! A man is filling a pool from 3 hoses. Hose A could fill it in 2 hours, hose B could fill it in 3 hours and hose C can fill it in 6 hours. However, there is a blockage in hose A,…
Karla
  • 1
0
votes
0 answers

Help with a puzzle from an old book

I found a very nice puzzle from a old book written in Spanish. I got stuck after a few hours, the only possible solution I found was that the numbers inside the circle have a kind of succession. For instance: We have 20 in the first circle, then…
alexandrenriq
  • 1
0
votes
1 answer

Riddle with 3 vessels that are empty in conditions

The problem is this we have a box that has in it 3 vessels which have the property that they empty their content once they are full. Their content is being emptied to the vessel to their right. Once the most right vessel is full then it just empties…
Anivos
  • 1
  • 2
0
votes
1 answer

Math riddle that 4 of us can't solve.

The riddle: How can 8+9+10=7. Our idea is that 8,9,10 is in a number base different from the number base that the answer 7 is in. We have tried several bases but can't find the answer. Any other idea is also welcomed.
L.G.
  • 1
0
votes
2 answers

Eye color probability puzzle

I went to a talk about probability paradoxes, and the speaker mentioned the following scenario (at least, this is how I recall it): One hundred people live on an island. Each person has green or blue eyes. Each person knows everyone's eye color…
TorsionSquid
  • 3,530
0
votes
1 answer

Find next number in matrix

I've been struggling with this puzzle for the last few days. We have square $$\begin{bmatrix} 3 & 6 & 2 & 8 \\ 2 & 1 & 1 & 3 \\ 1 & 3 & 1 & 4 \\ 5 & 5 & 3 & ? \end{bmatrix}$$ Question is what number we should insert instead of…
Kevin
  • 1
0
votes
1 answer

Find 2 numbers that the host chose.

The host chose 2 numbers x and y such that: - both of them are whole numbers - they are not smaller than 2, but not bigger than 100 - they are not the same number He gave the result of summing these numbers to the player no.1 and he gave the result…
Martin
  • 109
0
votes
0 answers

k of n aides to n ministers leak information; ministers only know whether other ministers' aides leaked (not their own)

I know the relationships between the ministers in the below problem can be represented by a $K_n$ graph since each one of the n ministers has connections to the n-1 other ministers/ministries they represent. However, I can't seem to figure out where…
fs24
  • 45
1 2 3
…
34 35