Why Aeroplane windows are round?

Count the number of squares in the picture below.

What work can one never finish?

Can you solve the maths in the below-given picture equation?

I have holes on the top and bottom. I have holes on my left and on my right. And I have holes in the middle, yet I still hold water. What am I?

A non-stop marathon is the shared favourite sport of three brothers.

*The oldest one is fat and short and trudges slowly on.
*The middle brother's tall and slim and keeps a steady pace.
*The youngest runs just like the wind, speeding through the race.

"He is young in years, we let him run!" the other two brothers explained, "'because though he is surely number one, he is second, in a way." Why is it?

If an electric train is travelling south, then which way is the smoke going?

Can you divide the below-given shape into four equal and identical pieces?

Two-person want to cross a river. Only one boat is present on the riverside that can carry only one person at a time.

However, they still manage to cross the river. How is it possible?

In 1990, a person is 15 years old. In 1995, that same person is 10 years old. How can this be?