Answer:
300 miles at 80 mph would take 3.75 hours.
Step-by-step explanation: If time is held constant, on the other hand, rather than distance, then the mean speed would be the average. 3 hours at 60 mph followed by 3 hours at 100 mph would yield an average speed of 80 mph. 180 miles, then 300 miles is 480 miles in 6 hours, or 80 mph.
