What is the coolest letter in the alphabet?

Which number should replace the question mark?

Forwards I am heavy, backward I am not. What am I?

A sea diver is a real show-off. He showed everyone that he can hold his breath underwater for 15 minutes.

I went to the diver and told him that I can be underwater for double the time i.e 30 minutes.
He responded that he will give me 100$ if I would be able to do it. I won 100$.

What did I do?

Solve the puzzle by telling what does below picture means.

I welcome the day with a show of light, I stealthily came here in the night. I bathe the earthy stuff at dawn, But by noon, alas! I'm gone.

In the four images below, can you find the odd one out?

How can you drop a raw egg from a height onto a concrete floor without cracking it?

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

Why are all black people so quick ?