a certain car uses 12 gallons of gasoline in traveling 420 miles . in order for the car to travel the same distance using 10 gallons of gasoline , by how many miles per gallon must the car ’ s gas mileage be increased ?
"420 / 10 = 42 the difference is 42 - 35 = 7 . answer d"
subtract(divide(420, 10), divide(420, 12))