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

What is the centre of gravity?

What always comes into a house through the keyhole?

In the picture, you can see a chess board. On the top left position, the K marks a knight. Now, can you move the knight in a manner that after 63 moves, the knight has been placed at all the squares exactly once excluding the starting square?

What is next number in the pattern below:

131 517 192 123 ?

Can you make numbers like 24, using numbers 3,3,7 & 7 with any arithmetic operator?

I got a bee but no honey.
got an eye but am still blind.
got a sea but no water.
got a tea but no coffee.
got a why but no answer.

What Am I?

What Adam and Eve do not have but the rest of the people have?

There was a kingdom in which the king had no heir to take over his thrown. Even the queen was dead and he himself was on the verge of dying. He thought about it and then summoned all of the teenagers. He gave one seed each to all of them and asked them to grow the plant. He announced that the one with the most beautiful plant will become the king/queen of the empire after the death of the king.

After a month, all of them were called. The king looked at all of the plants but announced the girl with an empty pot as the queen of the empire. Why?

By using 'because' continuously three times, can you make an English statement ?