On the highway, a car can travel 21 miles per gallon of gas. If the car travels for 4 hours on the highway at a rate of 65 miles per hour, how many gallons of gas should the car use, to the nearest tenth of a gallon?

Sanderson is having trouble with his assignment. his shown work is as follows: − 3 7 7 3 = − 3 7 × 7 3 = − 21 21 = −1 however, his answer does not match the answer that his teacher gives him. complete the description of sanderson's mistake. find the correct answer.