A salesman starts a trip with 15 gallons of gasoline in his tank. After traveling 220 miles he has 10 gallons of gasoline in his tank. Model this relationship with a linear equation relating the number of miles you can travel to the remaining gallons of gasoline. Explain what the x-intercept, the y-intercept, and the slope represent in this situation.

Answer 1

he drives 220 mi on 5 gal ... 44 mi/gal
... slope is the car's MPG

miles on remaining fuel is the range of the car
... range is DEPENDENT on gallons of fuel

gallons on x-axis ... range on y-axis

no fuel means no range
... both intercepts are zero (the origin)