The Mathematics Education Department
EMT 725, Lisa F. Garey

A Tangled Tale Problem

Click here for the Problem Statement

This is a problem that I have not been able to solve completely.

The entire trip took 5 hrs. The rates were 4 mph uphill, 3 mph on level ground, and 6 mph downhill.

Let the distance uphill and downhill be 2d = rt, where r=average rate for uphill & downhill, t=total time for uphill & downhill.



The total distance for the entire trip is given by the average rate multiplied by total time.

The average rate for uphill and downhill is 4.8 mph. The average rate for level ground is 3 mph. If the distances for level ground and uphill & downhill were equal, I could use the harmonic mean. However, this is not the case. I have tried proceeding as before, but I end with 1 equation and 2 unknowns.

 

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