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?

Can you write down eight eights so that they add up to one thousand?

What word is pronounced the same if you take away four of its five letters?

This is a famous paradox which has caused a great deal of argument and disbelief from many who cannot accept the correct answer. Four balls are placed in a hat. One is white, one is blue and the other two are red. The bag is shaken and someone draws two balls from the hat. He looks at the two balls and announces that at least one of them is red. What are the chances that the other ball he has drawn out is also red?

A man who was outside in the rain without an umbrella or hat didn’t get a single hair on his head wet. Why?

When can we add 2 to 11 and get 1 as the correct answer?

The centre of the third figure is empty. What digit should fit inside?

What is the next number?

77, 49, 36, 18 ?

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

P is the father of Q and S is the son of R. T is the brother of P and has a daughter U. If R is the sister of P, then what is the relation between U, Q and S?