Question

A car with 15 gallons of gasoline drives 420 miles until the tank is empty. Write a linear equation that describes the amount of gas left in the car, y, after driving x miles.

Answer 1

g = 15 - m/28

Explanation:

let g = gasoline

let m = miles

• g = 15 - m/28

since you can drive 420 miles with 15 gallons of gas, you can drive 28 miles with one gallon (= 420/15 = 28)

e.g.

you drive 100 miles, then you will have:

g = 15 - 100/28 = 15 - 3.57 = 11.43 gallons of gas left

you drive 240 miles:

g = 15 - 240/28 = 6.43 gallons