Once while in his court, King Akbar asked Birbal to write something on a wall that makes one sad when read in good times and makes one happy when read in sad times.

He took only a few moment and wrote something that fit the requirements. What did he write?

What am I?

There are 20 people in an empty, square room. Each person has full sight of the entire room and everyone in it without turning his head or body, or moving in any way (other than the eyes). Where can you place an apple so that all but one person can see it?

In a science lab, a petri dish hosts a healthy colony of yeast for an experiment. Now every minute, all the yeast cells divide into two. At noon, there was just a single cell of yeast and at 1:22, the Petri dish was half full. Can you calculate when the dish will be full of yeast?

Solve the puzzle by telling what does below picture means.

What can you catch but never throw?

By removing one matchstick and adding one matchstick, can you convert the word "ZOO" to an animal name?

You see a mathematical expression in the picture. Can you think of a movie that this expression refers to?

What does this simple rebus mean?

Which number comes next in the number series?

2, 9, 30, 93, ?