What always comes into a house through the keyhole?

Two friends were betting. One said to the other, "The coin will be flipped twenty times and each time the coin lands on the head, I will give you $2 and each time it lands on the tale, you will give me $3." After flipping the coin twenty times not a single penny was exchanged among them.

How many times did the coin land on heads?

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?

Which tank will fill first?

Count the number of balls in picture below:

Prove that twice of ten is the same as twice of eleven.

Spot 5 differences in two Christmas tree below:

What month of the year has 28 days?

Can you count the number of lines in the below picture?

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