What was their average speed?

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 only 4 miles per hour for the same distance. Not counting resting time, what was their average speed?

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The correct answer is 4.8, not 5, miles per hour. The answer is obtained by dividing the distance covered by the time elapsed, and any distance will do. Take a 12-mile run, for instance. That will take them two hours out and three hours back. It, therefore, took them five hours to travel 24 miles.

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