If 1+9+8=1, what is 2+8+9?

Find three numbers such that

* When we multiply three numbers, we will get the prime numbers.
* The difference between the second and the first number is equal to the third and second.

There was a man he lives in a hotel each morning he presses the first floor button each evening if there is a person in the elevator he asks him to press the 10 floor button if there is no one in the elevator he takes the stairs why.

The dirtier I get, the whiter I look. Who am I?

Which three-digit number, made of consecutive digits, like 567, is 2 less than a cube and 2 more than a square?

Can you find a seven digit number which describes itself. The first digit is the number of zeros in the number. The second digit is the number of ones in the number, etc. For example, in the number 21200, there are 2 zeros, 1 one, 2 twos, 0 threes and 0 fours.

John was piloting a plane behind a car but was never able to overtake it. Why?

When it is alive we sing, when it is dead we clap our hands. What is it?

An artist while painting a scenic beauty, decides to paint three layers of blue colour on the sky.

Which layer will go on the first?

You and your two friends are working in a multinational company. How can you three find out the average salary of you all without disclosing your own salary to the other two?