# All Questions

18,374 questions
Filter by
Sorted by
Tagged with
445 views

### The Dissection of R4-D2

Edit - Added hint to help decode the color tiles. You are back on Tatooine with R4-D2 (a descendant of R2-D2). During the journey to Herogga's pavilion, you encounter a fierce sandstorm. ...
2k views

### Using a balance scale the minimum number of times, find the median weight person

There are 15 person with different weights. What is the least number of tries required to find the middle (median) weight person? How? The only tools you have is your brain and a balance scale with ...
4k views

### The “M&M Sugar Rush” game

Suppose I have in my possession a incredibly large (almost infinitely large!) bag of M&Ms containing a uniform distribution of the 6 M&M colors. I'm bored, so I decide to play a game: I draw ...
1k views

### Hidden planet area

A solar system contains some number of stationary perfectly-spherical planets of equal radius. Call a point on a planet's surface private if it can't be seen from any other planet. Show that the total ...
1k views

### The Delayed Guessing Game

This is a similar but harder version of 6 Tries to Guess a Number Between 1-100. You friend gives you $n$ tries to guess an integer $x$, $1\le x\le 100$. Your guesses must be of the following type: ...
551 views

### Balancing all but one weight

You have an odd number of tokens whose weights are known whole numbers, and they don't all have the same weight. Show that there's a token you can remove so that the remaining tokens can't be split ...
1k views

### Picking a time to bet

You play a game with a friend: he deals cards face up one a time from a uniformly shuffled deck of 26 black cards and 26 red cards. At some point before all the cards have been dealt, you must call "...
1k views

### The juggling magician

In the magical circus, today a magician juggles with balls, cones, rings and umbrellas. While performing his art, he sometimes applies a powerful magic word: Ebrecedebre transforms one ball ...
5k views

### Ten numbers on a blackboard

The numbers 1 through 10 are written on a blackboard. You erase two numbers of your choice, and write their product plus their sum $$a,b \to ab+a+b$$ So, now there are nine numbers on the board. You ...
579 views

### Cows eat too much [closed]

Cows are always hungry... 70 Cows eat all the plants on a pasture in 24 days. 30 Cows clear the same pasture in 60 days. How many cows are needed to clear the pasture by the end of 96th day?
198 views

### Group of Farmers [closed]

A group of farmers need to harvest 2 farms, one of which is twice the size of the other. They worked half of the first day on the bigger farm. Then they split into two equal groups to work on ...
625 views

### Pathfinding with disappearing platforms - is it solvable?

This is a puzzle but might not have a solution. So "is it possible?" is a proper question. The puzzle idea was inspired by the question logic problem/puzzle solving, and if the puzzle here turns ...
2k views

### It tears me apart, one more time

'1' is not considered as a prime number. Find my true self, kill eleven Germans The good disguise wins so you act as twins Prime number 7 encrypted in alpha Now try to soften but please, not often ...
6k views

### How many triangles are in the picture?

In the below figure, how many triangles are there? Every line that seems straight is considered straight. Don't try to look for any sneaky stuff (the star shape drawer makes a weird curved top line ...
6k views

### What is the English word with the longest number of consecutive repeated letters?

Example: one repeated letter - bitter two consecutive repeated letters - bassoon three consecutive repeated letters - bookkeeper I've tried to find a four-times-repeated example but failed. (...
621 views

### logic problem/puzzle solving

I'm here to ask you if it is possible to find a way to solve this problem. I'm designing the puzzle-enigma section of a video game and try to find possible solutions and mechanic for it. Imagine each ...
9k views

### What is the minimum number of straight lines to connect all the dots on this grid?

Recently a question was posted with this picture of a 7x7 grid of dots, asking for a possible configuration with 12 lines where you can draw them without lifting a pencil. But is it possible with 11 ...
835 views

### Doubt : Pokemon Hunter and the Rogue Brook [closed]

I was working my way through some Puzzles in Discrete Maths by Rosen, when I came across the following question: A Pokemon Hunter is rowing upstream a brook As he passes under the 'bridge-of-...
5k views

### Infinitely many dwarves wearing hats of 2 colours

I have heard of the puzzle with 100 or 10 dwarves wearing a hat of a color, either red or blue, and standing in a straight line, and having to guess the color of their own hat - it's quite easy. The ...
1k views

### The billionaire's necklace

One day, the old billionaire summons his relatives in his study: "I'm very sick and may die soon, but the thought of all of you waiting for my death just to inherit the money makes me even sicker. ...
1k views

### Connect the dots

This will be a very straight forward puzzle accessible to anybody with no special skills required. In this grid of dots, draw 12 straight lines and connect all the dots. The lines must be drawn end ...
539 views

### Three 3 x 3 x 3 Polycube Dissections

The Soma cube is perhaps the most well-known polycube dissection. Here are three more dissections to be assembled into 3x3x3 cubes. The best answer will provide: the first correct solution for ...
3k views

### What country am I in?

Divide the length of my name by one letter, then multiply by 11 to get four times my meaning. What country am I in?
1k views

### A dead body, a pair of scissors, no bruises, no cut. How? [closed]

There's a dead body on a bed and on the floor is a pair of scissors. The scissors were instrumental to his death. Yet there was no trace of blood. The body reveals no sign of any cuts or bruises. How ...
7k views

### how many times 12 men may shake hands? [closed]

12 man participate in work Recruitment Service. Each participant saw every other participant and shook his hand. How many handshakes took place?
749 views

### Can the car or the bike travel further?

There is a car and a motor-bike. The car and the bike both have an spare tire. Now, the car has a total of 5 tyres (one spare tire included) and the bike has a total of 3 tires (one spare tire ...
391 views

Here are two figures, each composed of 54 pixels. Cut each figure into six nonominoes having the same shape and size. Both figures use the same nonomino The nonominoes could be rotated, reflected, ...
570 views

### The ill-posed word-search: A sick puzzle

This puzzle started out as ordinary 8-directional word-search puzzle, hiding 19 diseases amongst lots and lots of letters. But then, six letters were infected and became ill, and things became very ...
963 views

### The lights in the hotel

A hotel has $n$ rooms, numbered 1, 2, 3, etc. until $n$. At the hotel reception there are $n$ buttons, one for each room, also numbered 1, 2, 3, ..., $n$. Button 1 switches the light from on to off or ...
2k views

### The sands of life are running out

The one I obey, my dear commander Keep on running I will not slander For I know you will follow my lead Call me in if you are in need If one commands the other will follow That's the deal, one has ...
678 views

### Where am I located?

Note: Not a true story I am currently bored while idly thinking about how I got this job in VA. Sitting at a desk, I think about my work conditions while playing around on Inkscape. Below is the ...
2k views

### Lying, truthful and merciless guards (variation)

This is a variation of the riddle of 2 guards and 2 doors: You are stuck in a room with 3 doors. Each of the doors have a guard posted. One guard always tells the truth, one always lies, and the ...
3k views

### Find the secret message

The word under secret means something. What does it mean? (Find the secret message.)
356 views

### Object Representation [closed]

Background It isn't a common art style, but it is still done: using letters for form in pictures. Sometimes, people create art using only letters. Now, let us choose a word, i.e. Cool. 'Cool' can be ...
3k views

### Riddle Me This. What Object am I?

I am an object. Hard at heart, I can be shaped the same, Thickened, I added to Nostradamus's fame, My two faces are sharp or sweet While the air grows warm, I am a delightful treat Often in pairs, ...
17k views

### 10 Prisoners, 10 Keys, and 7 Years

One day, the warden of a prison is, like most wardens in puzzles, feeling a little bit capricious and decides that he wants to get rid of his prisoners, one way or another. He gathers all the ...
9k views

### Growing anagrams - What is the longest possible list forming a sentence?

This is a challenge for word-puzzle lovers. It might be a bit more of a game than a puzzle, but I think it is not limitless in it's answers, so a final answer could be found (eventually). What is ...
58k views

### A man with two red pills and two white pills

Story: A Color blind man is travelling in a somewhat famous ship that had just a few people on board. Everything was smooth sailing for some days. One day,the man heard some noises from outside when ...
800 views

### Stitching together two identical planar shapes

A 3 x 1 rectangle has a perimeter of length 8. Two of these rectangles can each be bend in a U-shape and stitched together to yield a cube of unit volume. Surely we can do better than that! What ...
2k views

### The Baconian Tower

The picture below depicts Sir Richard Mervyn Bacon, a (very) distant relative of Francis Bacon, leaving his flat on a clear autumns night in order to get his favourite book from the local library. ...
2k views

### Guess the other shape

Each solid shape is somehow related to the shape below it. Find this relationship and the correct shape for the last one. Edit: simplified second shape from left to a polygon
682 views

### Dissect the frog

Cut the stylized frog in the picture into six pieces having the same shape and size, possibly mirrored. The white dots are guide points. They help recognizing the shape's geometry. You are not ...
414 views

### Ten matches on a table

Ten matches lay on a table and look like this: "XI+I=X". They create a correct equality. What is this equality? (Write it in arabic numeral system in your answer).
360 views

### Riddle double-dactyl: Hollywood-Shmollywood

This is a riddle in double-dactyl form: Hollywood-Shmollywood Terrible ancients Are now resurrected In picture and sound. “Amateur fadsters!” cry ???????????????, “We liked them when ...
38k views

### If you choose an answer to this question at random, what is the chance you will be correct? [closed]

If you choose an answer to this question at random, what is the chance you will be correct? A) 25% B) 50% C) 60% D) 25%
590 views

As the human explorers ventured into an uncharted system, they got the feeling that their presence was expected. In fact, the stars themselves greeted them. What was the greeting?
435 views

### Friendly Golfers

We have 12 golfers and 3 foursomes everyday for 4 days. What is the formula so each golfer plays with everyone else at least once, but no more than twice. Obviously each golfer will only play twice ...
1k views

### What is the next number in this sequence?

Can you determine the next number in the below sequence? $1.0 , 4.0 , 6.9 , 9.0 , 10.8 , 12.0 , 14.0 , 16.0 , ?$ Bonus: Determine the next number that comes after '?' Note: I'll post some hints if ...
$1,20,171,?,9625,57756,288775$ Please find the missing number in the series. I have already tried with squares, cubes and progressions but couldn't find the problem.
In chess, Knights moves to squares a distance $\sqrt5$ away. Bishops move distances $\sqrt2$, $\sqrt8$, $\sqrt{18}$, etc. Both pieces are restricted to non-integer distance moves. Enter the Knishop, ...