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?

Solve the mathematical equation in the picture below.

Which English verb becomes past tense just by rearranging the letters?

Can you convert the number zero(0) into a positive number using just one mathematical operator ?

I am looking for a word that change both gender and number when i add the letter 'S'.

What Word am I Looking For ?

A number can be multiplied by multiple of nine
i.e 9 18 27 36 45 ...

and the resulting number consist of only one digit.

Can you identify the number ?

There are seven sisters in a house in a village where there is no electricity or any gadget.

Sister-1: Reading Novel
Sister-2: Cooking
Sister-3: Playing Chess
Sister-4: Playing Sudoku
Sister-5: Washing clothes
Sister-6: Gardening

what is Sister-7 doing ?

A train full of passengers goes through a tunnel. When the train comes out from the other end, there is no single person on the train.

How did it happen?

What does this rebus mean?

O
N
C
E
TIME

What is the four-digit number in which the first digit is one-third the second, the third is the sum of the first two, and the last is three times the second?