# All Questions

16,951 questions
440 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 ...
28k 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 ...
865k 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 ...
556 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 ...
700 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 ...
558 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 ...
1k 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, ...