What always comes into a house through the keyhole?

In 1990, a person is 15 years old. In 1995, that same person is 10 years old. How can this be?

Look at the picture and find out which square is not linked with any of the other squares.

what does the below math rebus puzzle mean?

When Jack was six years old he hammered a nail into his favourite tree to mark his height. Ten years later at age sixteen, Jack returned to see how much higher the nail was. If the tree grew by five centimetres each year, how much higher would the nail be?

What can jump higher than a building?

Can you replace the question mark with the correct number?

With pointed fangs I sit and wait; with piercing force I crunch out fate; grabbing victims, proclaiming might; physically joining with a single bite. What am I?

I have Rs.50 and I spend it in the way as below.

You find yourself in a strange place guarded by two guards.One of the guard always say truth while other always lies.You don't know the identity of the two.You can ask only one question to go out from there. What should you ask?