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Puzzle ID:#960
Fun:*** (2.35)
Difficulty:** (1.82)
Submitted By:Michelle***




A car travels at a speed of 30 mph over a certain distance, and then returns over the same distance at a speed of 20 mph. What is the average speed for the total trip?

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24 mph. Most people are quick to answer 25 mph, but this is not correct, as we will see. Let the distance traveled be 60 miles each way. Then, the trip out = 60/30 = 2 hours, and the trip back = 60/20 = 3 hours. Therefore: the 120 mile trip = 120/5 = 24 mph.

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