trouble with functions and domain/range

Question

Assume a car uses gas at a constant rate. After driving 25 miles since a full tank of gas was purchased, there was 9 gallons of gas left; after driving 70 miles since a full tank of gas was purchased, there was 7.2 gallons of gas left.

Use a function to model the amount of gas in the tank (in gallons). Let the independent variable be the number of miles driven since a full tank of gas was purchased. Find this function’s domain and range in this context.



Answer 1

So 1.8 gallons was used in 45 miles

45/1.8 = 25 mpg