You find yourself in a strange place guarded by two guards.One of the guard always say truth while other always lies.You don't know the identity of the two.You can ask only one question to go out from there. What should you ask?

What time is it when an elephant sits on a fence?

How much will a 38° angle measure when looked at under a microscope that magnifies ten times?

10+10 and 11+11 can give you the same answer.

Explain how?

The first box has two white balls. The second box has two black balls. The third box has a white and a black ball.

Boxes are labeled but all labels are wrong!

You are allowed to open one box, pick one ball at random, see its colour and put it back into the box, without seeing the colour of the other ball.

How many such operations are necessary to correctly label the boxes?

I sleep during the day and fly at night, but I have no feathers to aid my flight. What am I?

How many people must be gathered together in a room, before you can be certain that there is a greater than 50/50 chance that at least two of them have the same birthday?

What is the coolest letter in the alphabet?

Do you know of a place where the wind blows south and then suddenly shifts direction towards the north?

What you cannot hold but it is yours?