Question 1134632
if a man walks a distance at 3 mph and jogs back the same route at 5 mph and the trip takes  one hour  how many miles did he travel
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Avg speed for a round trip = 2*R1*R2/(R1 + R2)  where R1 and R2 are the 2 speeds.
The distance is not relevant if they are equal.
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Avg speed = 2*3*5/(3+5) = 30/8 = 3.75 mi/hr
--> 3.75 miles round trip
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This is the basis of the famous Michelson-Morley experiment in the mid-17th century that disproved the existence of the "ether."
google it.
Learn something.