a car travels 40 miles at an average speed of 80 mph and then travels 40 miles at an average speed of 40 mph. The average speed of the car for this 80 mile trip is: A) 80 mph B) 72.5 mph C) 60 mph D) 53.3 mph E) 40 mph

80mi/1.5hr = 160/3 mi/hr