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?

What has a ring but no finger?

Most people think of me as money. But when they find me in the water, they won’t get any money out of me. What am I?

A bomb exploded in a room full of married couples and no one died. How?

Imagine you are in a room with no windows or doors. How will you get out?

He runs but never walks. Murmurs, but never talks. Has a bed, but never sleeps. And has a mouth, but never eats?

What type of tree can I carry in my hand?

who is silent in the parliament?

What can jump higher than a building?

Take number 1000 and then add 20 to it.
Now add 1000 one more time.
Now add 30.
Now add 1000 one more time.
Now add 40.
Now add 1000 one more time.
Now add 10.

What is the total?