SOLUTION: A train covers its outward journey at 102 mph. It returns over same distance at 34 mph. What is the average speed of the train over the whole journey?

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Question 1072396: A train covers its outward journey at 102 mph. It returns over same distance at 34 mph. What is the average speed of the train over the whole journey?
Found 2 solutions by josgarithmetic, Alan3354:
Answer by josgarithmetic(39621) About Me  (Show Source):
You can put this solution on YOUR website!
system%28102%2Ax=d%2C34%2Ay=d%29

Total time,x%2By=d%2F102%2Bd%2F34
Total distance, 2d

Average rate of the whole journey, %282d%29%2F%28d%2F102%2Bd%2F34%29
2%2F%281%2F102%2B1%2F34%29

2%2F%281%2F102%2B3%2F102%29

2%2F%284%2F102%29

1%2F%282%2F102%29

highlight%2851%29

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
A train covers its outward journey at 102 mph. It returns over same distance at 34 mph. What is the average speed of the train over the whole journey?
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Avg = 2*102*34/(102+34) = 51 mi/hr
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It's similar to parallel resistors, parallel flows and parallel work.