Replace the question mark with the correct number.

A tree doubled in height each year until it reached its maximum height over the course of ten years. How many years did it take for the tree to reach half its maximum height?

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

What Time Should the last watch show in the below figure?

Can you solve the below rebus?

Which is faster, Heat or Cold ? Explain.

What time is it when an elephant sits on a fence?

How many words can a quill made with the feather of a pigeon write with a 100ml bottle of black ink?

In the picture, you can see a chess board. On the top left position, the K marks a knight. Now, can you move the knight in a manner that after 63 moves, the knight has been placed at all the squares exactly once excluding the starting square?

An infinite number of mathematicians are standing behind a bar. The first asks the barman for half a pint of beer, the second for a quarter pint, the third an eighth, and so on. How many pints of beer will the barman need to fulfill all mathematicians' wishes?