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

Explain how?

There was a strange boy who was born before his father. How can this be possible?

What has 13 hearts but no other organs?

Why are all black people so quick ?

Who has married many women but was never married?

Can you find out the number that should replace the question mark with a valid reason?

What happened when the wheel was invented?

If a shopkeeper can only place the weights on one side of the common balance. For example, if he has weights 1 and 3 then he can measure 1, 3 and 4 only. Now the question is how many minimum weights and names of the weights you will need to measure all weights from 1 to 1000? This is a fairly simple problem and very easy to prove also.

My first is in chocolate but not in ham. My second is in cake and also in jam. My third at tea time is easily found. Altogether, this is a friend who is often around. What is it?

If you're 8 feet away from a door and with each move you advance half the distance to the door. How many moves will it take to reach the door?