What's the average of 5 MPG and 10 MPG?
The math isn't quite obvious to me, but if you go out camping and get 5 MPG on the way to the campground and turn around and get 10 MGP on the way back, your average MPG won't be 7.5 as you would expe...
Forum Discussion
dave54 wrote:
http://www.cut-the-knot.org/arithmetic/HarmonicMean.shtml
In math geek talk average and mean are not the same thing. There are different kinds of means, one of which is the arithmetic mean, commonly called average. This problem uses the harmonic mean.
This is the answer. Harmonic mean is used to average rates and MPG is a rate (miles PER gallon). So the average of 5mpg and 10mpg is 2 / ( 1/5 + 1/10 ).
