Take away my first letter, then take away my second letter. Then take away the rest of my letters, yet I remain the same. What am I?

Can you make a six-letter word using the letters N, A and B ?

I have no life, but I can die. What am I?

In the four images below, can you find the odd one out?

There are 20 people in an empty, square room. Each person has full sight of the entire room and everyone in it without turning his head or body, or moving in any way (other than the eyes). Where can you place an apple so that all but one person can see it?

Name a key which is hardest to turn.

What is so fragile that saying its name breaks it?

Can you find the key in the picture below?

Solve the mathematical equation in the picture below.

You are trapped in a room with two doors. One leads to certain death and the other leads to freedom. You don't know which is which.
There are two robots guarding the doors. They will let you choose one door but upon doing so you must go through it.
You can, however, ask one robot one question. The problem is one robot always tells the truth, the other always lies and you don't know which is which.
What is the question you ask?