Replace the question mark with the number below given a simple math problem.

What is the coolest letter in the alphabet?

Sherlock Holmes was challenged to make a pre-drawn line smaller without erasing it. He did it in fractions of seconds. How?

What famous saying does this rebus mean?

COME SERVED <---
COME SERVED
COME SERVED
COME SERVED
COME SERVED

Can you find the missing number in the third row?
35 20 14
27 12 18
5 2 ?

My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

How many points are there on the globe where, by walking one mile south, then one mile east and then one mile north, you would reach the place where you started?

In order to complete the racing competition, the Mexico racetrack has to submit its top and the most famous three horses to win the competition. Due to an electrical storm, all the records are cleared and no one knows which horse holds the record. They all look identical and it becomes even more difficult to differentiate the horses. There are 25 horses in the Mexico racetrack. But there can be only five horses at a time on the track. What will the least number of races that can be conducted to find out the three fastest horses?

Today is John's birthday.
A year ago, John had five candles and he lit all the candles except the one at the last.
Now he is going to light all the candles.

How old is John Today?

(He is not five today.....)

Different lights make me strange by changing me into different sizes. What am I?