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?

Through your logical capabilities, can you make 7 an even?

John was a very careless driver, so his owner Jacob gave him an offer that he will get an incentive of Rs.30 for every bottle box he delivered without breaking it and he will be charged Rs.90 for every bottle box he broke. Jacob gave John 100 bottles-box to deliver. After delivery, Jacob paid John Rs.2400. How many bottles-box did John break?

When monkey rotate the gear, which mark will be hit 1 or 2 ?

There are two guys standing face to face in a room. On a wall, there is a clock. One of those is a prophet. He tells the other guy that he will be stabbed in the back in five minutes.

Shocked to hear that, the other guy stares at the clock. Just after the five minutes, he is stabbed on the back. Can you tell what happened?

A man lives on the fifteenth floor of an apartment building. Every morning he takes the elevator down to the lobby and leaves the building. In the evening, he gets into the elevator, and, if there is someone else in the elevator, or if it was raining that day, he goes back to his floor directly. Otherwise, he goes to the tenth floor and walks up five flights of stairs to his apartment. Can you explain why he does this?

Samuel was out for a walk when it started to rain. He did not have an umbrella and he wasn't wearing a hat. His clothes were soaked, yet not a single hair on his head got wet. How could this happen?

If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

Can you convert the number zero(0) into a positive number using just one mathematical operator ?

Take away the whole and some still remain. What is it?