Mr. Harper's car used 5 gallons of gasoline to travel 150 miles. After he had some work done on the cars engine ,it used it used 6 gallons of gasoline to travel 210 miles. If the price of gasoline was $3.50 per gallon, how much money did Mr. Harper save per mile after the work was done on the cars engine? (Round your answers to the nearest cent.)

Answer:He saves $0.0175 per mileStep-by-step explanation:Before the work done on the car´s engine, it took 0.033 gallons to travel one mile ( 5 gallons /150miles =0.033). After this work, the car spends 0.028 gallons to travel one mile (6 gallons/210 miles =0.028). The difference between this two is:0.033 gallons/mile-0.028 gallons/mile= 0.005 gallons per mile.Now Mr.Harper´s saves 0.005 gallons per mile.In money he saves:$3,50/gallon*0.005 gallon/mile= $0.0175/mile (the unit of "gallon" cancel each other)Rounded to the nearest cent:He saves $0.0 per mile.