Two youngsters were running as hard as they could. They averaged 6 miles per hour and then had to rest. On the way back they averaged 4 miles per hour for the same distance. Not counting resting time, what was their average speed?
4.8 miles per hour. 5 is incorrect. Take any distance (say 12 miles there and 12 miles back). They take two hours to cover the first 12 miles and three hours to cover the return trip. In 5 hours they covered 24 miles which is an overall average of 4.8 miles per hour.
