# All Questions

18,408 questions
Filter by
Sorted by
Tagged with
1k views

### Integer grid problem

I found this programming related problem too difficult for me. The problem asks to find 16 integers and form a 4x4 grid \left(\begin{array}{cccc} n_1 & n_2 & n_3 & n_4 \\ n_5 & n_6 &...
9k views

### Divide a rectangle with a rectangular hole into two equal parts

Consider any large rectangle from which a smaller rectangular portion has been removed. The removed rectangular portion may have any orientation i.e. the remaining figure is not necessarily symmetric ...
486 views

### Products of three primes that bound RSA numbers [closed]

Let $N$ be some number. Let $R$ and $S$ be semiprimes (ie, each is a product of two prime numbers) such that $R \le N \le S$. For quite a few numbers $N$ we can find $R, S$ such that $S-R$ is small;...
1k views

### Entangled physicists

The anti-intellectuals have won the war, and under the iron rule of emperor Nonotin anyone who has been deemed too smart for their own good has been brought to labour camps. But most of the science ...
1k views

### Find the order of students presentation(logical puzzle)

Four students P, Q, R and S each working under the super vision of one of the four professors A, B, C and D made their final year MBA Project Presentations one by one, one each in the areas of Finance,...
740 views

### Find the pattern of matrices

fill the matrix correctly and the guess the Letter and number of 5th matrix: PS: I'm sure you won't need options!
2k views

### The defective clock

James has a defective clock in his room. The clock is digital, and some of the seven bars on its units digit are broken. A bar that works is on when it should be and off when it should be, whereas a ...
445 views

### How to control the whole board with 8 standard pieces?

How to control the whole board with 8 standard pieces (one king, one queen, two rooks, two knights, two bishops)? P.S. A piece doesn't control a cell simply by staying on it, so another piece must ...
1k views

### is there any sudoku puzzle combined with magic square?

As everyone know in Sudoku sum of each row and column is 45. so all Sudoku solutions are some kind of magic square. but my question is: Have anyone seen a Sudoku puzzle combined with the magic ...
2k views

### Find the next number in the series?

Find the value of 'a' and 'b' in the following series. 100,101,120,103,410,321,205,404,60a,5b2
3k views

### Color the Table

Color each cell of the table with following rules: Yellow and Orange cells are adjacent, but Red and Black are not. Cell with number 3 is White, Green, Blue or Red and the cell with number 5 is not ...
31k views

### Split 12 liters in half with 5 and 8 liter bottles [duplicate]

You have 12 liters of apple juice in a 12 liters bucket and you want to share it with your best friend. But you have an empty 8-liter and an empty 5-liter bottle. How do you split the apple juice in ...
3k views

### The seven piece silver chain

You have to stay for 7 days in a hotel outside your city. But you forgot to bring your credit card and are out of cash. You have a silver chain with 7 links. The rule in this hotel is that residents ...
936k views

### Two doors with two guards - one lies, one tells the truth

You are a prisoner in a room with 2 doors and 2 guards. One of the doors will guide you to freedom and behind the other is a hangman --you don't know which is which. One of the guards always tells ...
580 views

### Which one is the lightest marble?

There are 8 marbles that one of them is lighter than the others, and all other seven marbles have the same weight. There is a balance scale that you can use it twice or once. Is there any way to find ...
713 views

### Find the Different Sugar Cubes [duplicate]

There are 10 Boxes, each contains 1000 sugar cubes. The sugar cubes in 9 of the boxes are 10 grams each and the other box has 9 gram cubes. There is a digital scale that you can use it ONCE. (i.e. ...
1k views

### What is the purpose of a weird non-linear watch dial that goes up to 100? [closed]

Can anyone tell me what is the purpose of the outter dial of this watch? Notice how the scale is not linear and goes to 100. It can only be rotated counter-clockwise only. This is the only picture I ...
561 views

### A cube puzzle (Multiple of 6)

If you have a cube, say, $3 \times 3 \times 3$, you know that mathematically it's made of $27$ ($3*3*3$) smaller cubes. Now, just remove one full line of smaller cubes (in this case, 3 smaller cubes). ...
4k views

### Confused about step 5 of official Rubik's 3x3 Cube solution

Solution guide: http://rubiks.com/uploads/general_content/Rubiks_cube_3x3_solution-en.pdf I can get to this point pretty reliably now, but when I try the method shown I'm just as likely to go from ...
1k views

### Unknown Consecutive Integers Puzzle

Two people, Anne and Bob, each hold an index card. A positive integer is printed on each index card, and these integers are consecutive (i.e. Anne's card may display 8 and Bob's card 7). Anne and Bob ...
3k views

### The Monty Hall problem

I'm amazed that, although well known, this problem hasn't been posted yet. Monty Hall You are on a game show. The host of the show shows you three doors. He tells you that behind one of them, is a ...
2k views

### Three 50/50 guesses

Three friends enter a quiz-show as a team, the final round of the show is all or nothing, they only get their prize if they can win this round. Three boxes labelled 1, 2 and 3 are placed in a room, ...
6k views

### The lake monster

You are on a rowboat in the middle of a large, perfectly circular lake. On the perimeter of the lake is a monster who wants to eat you, but fortunately, he can't swim. He can run (along the perimeter)...