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?

Can anyone tell me a word in the English dictionary which has a silent 'z'?

An office is divided into 8 cubicles. How many of the cubicles are painted if only 1/8 of the cubicles are painted?

Assume there are approximately 5,000,000,000 (5 billion) people on Earth. What would you estimate to be the result, if you multiply together the number of fingers on every person's left hand? (For the purposes of this exercise, thumbs count as fingers, for five fingers per hand.) If you cannot estimate the number then try to guess how long the number would be.

What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

I have teeth but i don't bite. Who Am I ?

The two towns are exactly 100 km apart. John leaves City A driving at 30 km/hr and Jacob leaves City B half an hour later driving at 60 km/hr. Who will be closer to City A when they meet?

How can you make the following equation true by drawing only one straight line: 5+5+5=550 ?

"That Restaurant always remains crowded. This is the reason why nobody goes there".

Can you find a flaw in this statement?

I am the fastest animal but cannot climb the tree. What am I?