What has a ring but no finger?

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?

Use only one mathematical symbol and all numbers (0-9) to get a sum of 99

Find the next number in the series

12, 20, 40, 72, 116, 172 ?

Which number should replace the question mark?

Can you find out the number of the parking space in which the car is parked?

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

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

Sachin bought a car with a strange 5 digit numbered plate.The water image of the number is 78633 more than my car number. All the digits of car number are distinct.

What is the original number on number plate?

Can you find out who is the kidnapper in below Picture and why, Explain ?