How many gallons of gas are in the tanks on Day 13?

Question

You are using a gas-powered generator to run a motor that uses gas energy at a constant rate regardless of the level in the tank. You have the gas tank filled to maximum capacity on Day 0, and immediately start the generator. At the same time of day, on Day 4 the level in the tank reads 10.2 gallons, and on Day 10, the level in the tank reads 6.6 gallons.

Answer 1

In 6 days (10- 4), the gas has gone down 3.6 gallons.

That is 0.72 gallons peer day.

In the next three days it shall lose 2.16 gallons

 

What shall be the level?