What is the fastest way to double your money?

In a school, there are four subjects. Seventy percent of students study English, seventy five percent of students study Science, eighty five percent of students study Mathematics and eighty percent of students study Spanish.

Can you calculate the percentage of students that study all four subjects?

A bomb goes off.
Carnage.
One person, only a few feet away, survives! How can this be?

Outside a massage parlour, there is a board that reads
"I only massage those who do not massage themselves."

Reading the above statement, does the masseur massage himself?

Get total of 120 by using five zeros 0,0,0,0,0 and any one mathematical operator.
Do you ?

Why is Saturday stronger than Monday?

No matter how little or how much you use me, you change me every month. What am I?

You need to move three matchsticks to form three squares. Can you do it?

How is the moon similar to a dollar?

I am looking for a word that change both gender and number when i add the letter 'S'.

What Word am I Looking For ?