Alice, Bob, and Cindy each drive 1000 miles per month. Alice averages 40 mpg, Bob averages 20 mpg, and Cindy averages 40 mpg. Computing the regular arithmetic mean of the 3 mpg will lead to an incorrect average. First, invert each mpg to get gpm then compute the arithmetic mean, then re-invert back to mpg ('Harmonic Mean'). Second, find the total number of miles driven and total number of gallons used, then divide. Execute one or both of these methods and compare/ contrast to the incorrect arithmetic mean. Each person plans on buying a newer, more efficient vehicle. Alice's new truck will get 13mpg. Bob is upgrading to a 28mpg car, and Cindy is looking at a 55mpg hybrid. Who will save more gasoline with these upgrades? What upgraded mpg would the other two need in order to save the same amount? First, compare the gpm for each person's new vehicle vs. old vehicle. Next, find out how many gpm are saved by each person. Finally, take the most saved gpm and apply that savings to the other two persons before inverting back. Second, compare the gallons used for each person's new vehicle vs. old vehicle (for each month). Next, take the largest saved number of gallons and apply it to the other two. Execute one or both of these methods and summarize.