what does the below math rebus puzzle mean?

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?

I’m tall when I’m young, and I’m short when I’m old. What am I?

The product of three consecutive numbers is 7980.
Then the sum of these consecutive numbers would be?

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

How can you make the following equation true by drawing only one straight line: 5+5+5=550 ?

With pointed fangs I sit and wait; with piercing force I crunch out fate; grabbing victims, proclaiming might; physically joining with a single bite. What am I?

As you can see that fifteen matches have been used to form an arrangement. What you have to do is remove any six of them to make them ten.

John buys rice at Rs.60/kg from Britain and then sells them at Rs.5/kg in India. As a result of this, he becomes a millionaire. How come?

If your uncle’s sister is not your aunt, what relation is she to you?