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?

How could a baby fall out of a twenty-story building onto the ground and live?

You can hear me, but you can't touch or see me.

What am I?

Twice ten are six of us,

Six are but three of us,

Nine are but four of us;

What can we possibly be?

Would you know more of us?

Twelve are but six of us,

Five are but four, do you see?

What are we?

Can you count the number of triangles in the picture below?

Take away my first letter, then take away my second letter. Then take away the rest of my letters, yet I remain the same. What am I?

Can you solve the below tricky visual equation?

I have branches, but no fruit, trunk or leaves. What am I?

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

You can take four of the five letters out of this word, but the pronunciation never changes. What is the word?