How can a man go eight days without sleep?

Can you find out the remainder when 3^300 is divided by 5?

What does this rebus puzzle means ?

What begins with T, ends with T, and has T in it?

What does this simple rebus mean?

Luis Garavito killed Density x Volume.

Who is Luis Garavito ?

What is in seasons, seconds, centuries and minutes but not in decades, years or days?

Birbal was jester, counsellor, and fool to the great Moghul emperor, Akbar.
The villagers loved to talk of Birbal's wisdom and cleverness,
and the emperor loved to try to outsmart him.
One day Akbar (emperor) drew a line across the floor.
"Birbal," he ordered, "you must make this line shorter, but you cannot erase any bit of it."
Everyone present thought the emperor had finally outsmarted Birbal.
It was clearly an impossible task.
Yet within moments the emperor and everyone else present had to agree that Birbal had made the line shorter without erasing any of it.
How could this be?

In the attached figure, you can see a chessboard and two rooks placed on the chess board. What you have to find is the number of squares that do not contain the rooks. How many are there?

Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?