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?

I cry without having a voice.
I fly without having wings.
I bite without having teeth.
I whisper without a mouth.

Who am I?

What is the centre of gravity?

Find the smallest sentence with all the English alphabet.

Which is the rope you never skip with?

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see? What is it?

Through your logical capabilities, can you make 7 an even?

Who can jump higher than a Mountain?

A man has a barrel filled with oil that weighs 100 pounds, and then he puts something into it. Now the barrel weighs less than 100 pounds. What did he put in the barrel?

Prove that the below maths equation is true.

8 + 8 = 91