Rearrange the letters in "new door" to make one word.

How many triangles are there on the puzzle below?

What has many keys but can’t open a single lock?

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?

French Police inspects a room where there are no windows, no doors, no tables and is almost empty expect there is just a puddle of water. They found a dead man who obviously hung herself from the ceiling, but they are not able to figure out how this had happened.

John and Jacob entered the crime scene and easily able to solve the case.

How did the man die?

There were two grandmothers and their two granddaughters.
There were two husbands and their two wives.
There were two fathers and their two daughters.
There were two mothers and their two sons.
There were two maidens and their two mothers.
There were two sisters and their two brothers.
Yet there are only six, who are buried here,
All are born legitimate and relationships clear.
How can this happen?

If you remove one from eleven, it becomes ten. If you remove one from nine, it becomes ten.

How is this possible?

How can you write nineteen in a manner that if we take out one, it becomes twenty?

Solve the below puzzle by replacing the question mark with the correct number.

3 6 12

4 8 16

5 10 ?

Can you find out a way through which you can make five squares out of the given figure by moving just six match sticks?