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

Explain how?

There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?

A mother is 21 years older than her child. In exactly 6 years from now, the mother will be exactly 5 times as old as the child.
Where's the father?

A pet show was happening in my locality. I went down along with my kids. In that show, I noticed that all except two of the entries were cats. All except two were dogs and all except two were Monkeys.

Can you find out how many of each animals were present in that pet show?

Railroad Crossing, look out for the cars. Can you spell that, without any R's ?

Count the number of balls in picture below:

How can a man go eight days without sleep?

In the below-given picture of a pretty girl, there is something wrong. Can you find out what it is?

Two guards were on duty outside a barracks. One faced up the road to watch for anyone approaching from the North. The other looked down the road to see if anyone approached from the South. Suddenly one of them said to the other, "Why are you smiling?"

How did he know his companion was smiling?

John said, "If yesterday was tomorrow, today would be Friday."

When did John make this statement?