It took Brenda 10 hours to drive from A to B when she averag

It took Brenda 10 hours to drive from A to B when she averaged 50 miles per hour. Pulling a trailer on the return trip from B to A, she averaged 40 miles per hour. How many hours did the return trip take?

Solution

10 hrs at 50 mph means the distance from A to B is 500 miles
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Time for the return trip = distance/rate = 500/40 = 12.5 hours