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?

In The 1st month of this year(the year 2013), I noticed that the date 13-1-13 (13 January 2013) is special.

This date is special as:

Date * Month = Year.

Can you figure out which year of this century has a maximum number of such dates?

This puzzle is for Harry Potter fans. Do you know why Tom Riddle is called Lord Voldemort?

I know a ten-letter word in the English language which can be typed using only the top rows of the computer keyboard.

Solve the counting riddle by identifying the number of triangles in the given picture.

A girl says this to her best friend: “I was born in 1955, and I celebrated my 17th birthday last weekend.” Her best friend thinks she’s lying, but she’s actually correct. How is that possible?

Until it is measured, not known. Yet how you miss it when it has gone. What is it?

You can hear me, but you can't touch or see me.

What am I?

What jumps when it walks and sits when it stands?

Can you think of any three-dimensional shape that comprises of exactly two surfaces?