Pop quiz: Say you split your driving evenly between a 21 mpg SUV and a 75 mpg Vespa scooter. What would your average miles per gallon be? If you answered 48 mpg you're not alone, as that's what Vespa came up with in their infographic we posted last week (reposted above). The only problem is that that answer is wrong. The real average is 32.8 mpg.The reason for the large difference is that in order to correctly calculate average mpg, you can't simply add both numbers and divide by two. You have to first convert to gallons per mile (gpm), then average. We've discussed gpm before and have featured a graph on the subject here, but both of those posts are a few years old so we thought this was a good time for a refresher.

If Vespa is having trouble with the math, the average consumer isn't likely to fare much better. Of course, if we just switched over to the metric system and measured in liters/km, like most of the rest of the world, we wouldn't have this problem. Fat chance, we know.

In any case, it seems someone informed Vespa of this error after the infographic was released. The company quietly changed the infographic values on its website.


I'm reporting this comment as:

Reported comments and users are reviewed by Autoblog staff 24 hours a day, seven days a week to determine whether they violate Community Guideline. Accounts are penalized for Community Guidelines violations and serious or repeated violations can lead to account termination.


    • 1 Second Ago
  • From Our Partners

    You May Like
    Links by Zergnet
    Cars for Sale Near You

    Share This Photo X