If it took eight men ten hours to build a wall, how long would it take four men to build it?

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

The barber of Town shaves all men living in the town. No man living in the town is allowed to shave himself. The barber lives in that town. Who then shaves the barber of the town?

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?

What has hands, but can’t clap?

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

Rearrange the letters in "new door" to make one word.

How can a man go eight days without sleep?

What building has the most stories?

When can we add 2 to 11 and get 1 as the correct answer?