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?

Count the number of squares in the picture below.

A train full of passengers goes through a tunnel. When the train comes out from the other end, there is no single person on the train.

How did it happen?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

Can you count the number of blocks in the picture below?

What can go up a chimney down, but can’t go down a chimney up?

A girl rode into a tourist spot out of the city on Thursday. She loved the place and decided to stay for a few days. She stayed for four days and then she left for back home on Thursday.

How can this be possible?

You need to pick one entry from pot A and one from pot B to have a perfect match. Can you do it?

Solve the equation by replacing the alphabet with numbers.

MOM + MOM + NO = BOOK=

Can anyone tell me a word in the English dictionary which has a silent 'z'?