A car traveled from A to B at an average speed of 40 miles p

A car traveled from A to B at an average speed of 40 miles per hour and then immediately traveled back from B to A at an average speed of 60 miles per hour. What was the car

d = 40t1
t1 = d/40
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d = 60t2
t2 = d/60
Avg = 2d/(t1 + t2)
Avg = 2d/(d/40 + d/60)
Avg = 2/(1/40 + 1/60) = 2/(25/600) = 1200/25
Avg = 48 mph
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