Question 791282
A car travels along a certain road at an average speed of 40 km/h, and returns along the same road at an average speed of 60 km/h. Calculate the average speed for the round trip. (Don't say 50 km/h!)
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Avg speed for a round trip = 2*r1*r2/(r1 + r2)
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2*40*60/(40+60)
48 mi/hr
This is true regardless of the distance.
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