How can you make number one disappear by adding something to it?

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?

Consider this: Arnold Schwarzenegger has a big one. Michael J. Fox has a small one. Prince doesn’t have one. The Pope has one but never uses it. Bill Clinton has one and uses it all the time. What is it?

What demands an answer, but asks no questions

Kareena is older than Katrina and younger than Karishma. Isabelle is younger than Bipasha and Karishma. Bipasha is older than Karishma. If Kareena and Isabelle are the same age, who's the youngest?

There is a place where if I stand up straight, I will still be considered sideways.

What jumps when it walks and sits when it stands?

Replace the letters of words with a number so that the below equation holds true

BASE +
BALL
---------
GAMES
----------

There is something which you can be arrested for attempting but not for successfully completing.