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

There was once a college that offered a class on probability applied to the real world. The class was relatively easy, but there was a catch. There were no homework assignments or tests, but there was a final exam that would have only one question on it. When everyone received the test paper it was a blank sheet of paper with a solitary question on it: 'What is the risk?'.Most students were able to pass, but only one student received 100% for the class! Even stranger was that he only wrote down one word!
What did he write?

Why is Saturday stronger than Monday?

It's a 7-letter word.
If we remove 1 letter from it, it remains the same.
If we remove 2 letters from it, it remains the same.
If we remove 3 letters from it, it remains the same.
If we remove all the letters from it, still it remains the same.
What is it?

I know a country, If you remove the last alphabet of its name, it will become a part of your body. Do you name it?

What has a bottom at the top?

Outside a massage parlour, there is a board that reads
"I only massage those who do not massage themselves."

Reading the above statement, does the masseur massage himself?

10+10 and 11+11 can give you the same answer.

Explain how?

Why is it very easy to weigh a fish?

Why do people go to bed?