Why Aeroplane windows are round?

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see? What is it?

I have eight fingers and two thumbs but I do not live. What Am I?

Replace The Question Mark Below With the Correct Number.

2 {38} 3
4 {1524} 5
6 {3548} 7
8 {????} 9

I sleep during the day and fly at night, but I have no feathers to aid my flight. What am I?

How many triangles can you count in the figure given?

Find three numbers such that When we multiply three numbers, we will get the prime numbers. The difference between the second and the first number is equal to the third and second.

There are two insects on a tile. Insect X is sitting on one side of the tile (point A) and Insect Y is sitting opposite on the other side of the tile (point B). Now both of them decide to change their position and thus X starts crawling to point B and Y starts crawling to point A. When they meet and pass each other in between, X takes 20 seconds to reach B and Y takes just 5 seconds to reach A.

Can you calculate the total time each of the insects took to change their positions?

What is the largest amount of money that you can possess in change and still if someone asks you for a dollar, you won't be able to give?

A man who was outside in the rain without an umbrella or hat didn’t get a single hair on his head wet. Why?