I am the one who remains awake when you sleep. But I need to rest when you awake. Who Am I?

Before the start of the car race, John and Jacob have the same amount of fuel in their car. With this fuel, John can drive for 4 hours while Jacob can drive five hours.
After a time they realize that the amount of fuel left in John's car is 1/4th of the fuel in Jacob's.

For how long they are racing?

The person who makes it has no need for it. He who purchases it does not use it. The person who does use it does not know they are. What is it?

The captain of a ship was telling this interesting story: "We travelled the sea far and wide. At one time, two of my sailors were standing on opposite sides of the ship. One was looking west and the other one east. And at the same time, they could see each other clearly." How can that be possible?

Replace the question mark with the correct number in below Picture:

In the below-given picture of a pretty girl, there is something wrong. Can you find out what it is?

I start and end with 500 and carry a 5 in my heart. But I require the first letter and the first number to be complete. I am the name of a King.

Who am I ?

Whats the next number in the below number sequence pattern.

By including only four matchsticks in below picture, you have to make "Four Triangles And Two Squares"

Find out the missing number in the picture attached: