What is the coolest letter in the alphabet?

Solve the mathematical equation in the picture below.

There are 20 people in an empty, square room. Each person has full sight of the entire room and everyone in it without turning his head or body, or moving in any way (other than the eyes). Where can you place an apple so that all but one person can see it?

Can you decipher the below rebus?

PBLUESAISNUERSES

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

Spelt forwards I’m what you do every day, spelled backwards I’m something you hate. What am I?

In a stable, there are men and horses. In all, there are 22 heads and 72 feet. How many men and how many horses are in the stable

What country can make you shiver?

Decode below three cipher riddles:

26 L of the A
7 D of the W
1000 Y in a M

How old is your son? asked a man to his neighbour. My son is five times as old as my daughter and my wife is five times as old as my son. I am twice as old as my wife whereas my grandmother, who is celebrating her eighty-first birthday is as old as all of us put together.

How old is the man's son ?