What's the only room from which no one can enter or leave

Can you write down eight eights so that they add up to one thousand?

I am quite hot but become too cold if you remove the first two letters. What am I?

Solve the equation by replacing the alphabet with numbers.

MOM + MOM + NO = BOOK=

Can you identify the hidden rebus in the image below?

John has played 50 ODI's and his average is 50. How many runs should he score in his 51st ODI, so that his average score jumps to 51?

Mother's Name is Mrs. SIXTY TWO
Son's Name is FIFTY TWO
Daughter's Name is FORTY TWO
What is Name of Father?

Below the four parts have been reorganised. The four partitions are exactly the same in both arrangements. Why is there a hole?

There are are five things wrong with this sentence; only geniuses will be able to to spot all of the mitstakes

You are in a room with no metal objects except for two iron rods. Only one of them is a magnet.
How can you identify which one is a magnet?