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?

I cannot talk, but I always reply when spoken to. What am I?

There are 3 apples in the basket and you take away 2. How many apples do you have now?

Three fair coins are tossed in the air and they land with heads up. Can you calculate the chances that when they are tossed again, two coins will again land with heads up?

What has no start, end, or centre?

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

Out of four images which one is the odd one out?

Can you find a number that lies one third of the distance between 1/3 and 2/3?

What can you hold in your right hand, but never in your left hand?

In the picture given below, can you find out which digit will take place of the question mark?