SOLUTION: A bicyclist rides for 2h at a speed of 10 mph and then returns at a speed of 20 mph. find the cyclist average speed for the trip?

Question 476190: A bicyclist rides for 2h at a speed of 10 mph and then returns at a speed of 20 mph. find the cyclist average speed for the trip?
Found 2 solutions by jorel1380, Alan3354:
Answer by jorel1380(3719) (Show Source): You can put this solution on YOUR website!
2hx10 mph=20 miles
20 miles/20 mph=1 hour
40 miles/3 hours=13.333 mph..
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
It's similar to parallel resistors, but times 2
Avg speed = 2*product/sum = 2*10*20/(10 + 20) = 400/30
= 13.33 mph
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Notice the distance is not relevant.
This was used in the Michelson-Morley experiment to disprove the existence of the ether, in 1840.
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