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?

It's a protector.
It sits on a bridge.
One individual can see directly through it, while others wonder what it hides.

What is it?

What can you serve, but never eat?

When we see 2 but call 10?

How can you make a TV, a bed, a dog, and a car liquid?

This puzzle is for Harry Potter fans. Do you know why Tom Riddle is called Lord Voldemort?

The answer I give is yes, but what I mean is no. What was the question?

Prove that twice of ten is the same as twice of eleven.

What is the centre of gravity?

There is a rock group of four men that do not sing. Name It?