MPG Math Question

[Matt Herring]

Can anyone tell me the answer to this...I'm either too lazy or not "edimicated" enough to figure it out...

I recently moved and have a new route to work. My new route is 11 miles one way and my scanguage on my first two trips to work has registered roughly 20 mpg on the trip.

My old commute was 4 miles one way and my last several trips averaged roughly 17 mpg on the scanguage.

Here's the question...

Obviously, the new commute is producing better mpg results (mainly due to better coasting hills and the ability to drive in less crowded traffic on higher mph roads). But, I'm wondering over the course of a tank does the added mpg on the new route actually save me money considering I am driving 11 miles to work now instead of 4 miles (or 22 miles roundtrip vs. 8)? What mpg on my new route would I have to get to equal my usage on the old route?

You can estimate the new route vs. old route on a 400 mile tank.

Any answers are greatly appreciated! Thanks!

[Matt Herring]

I did a little math...or attempted to...

I get 3 more mpg on the new route vs. the old route so at $2 a gallon I think I save $6 a tank (based on a 400 mile tank). But...because my daily round trip commute is 22 miles and not 8 miles I use more fuel. So...still wondering what mpg I would need to pull on the new route to break even vs. the old route. Kind of looking for a "goal" on the new route to at least keep my fuel conservation numbers equal or near my old route.

[KJSatz]

An 8 mile round trip at 17 miles per gallon gives you (8 miles)/(17 miles/gallon) = .47 gallons.

To travel 22 miles using .47 gallons you would need to get (22 miles)/(.47 gallons) = 47 miles per gallon.

[jkline27]

Originally Posted by KJSatz

An 8 mile round trip at 17 miles per gallon gives you (8 miles)/(17 miles/gallon) = .47 gallons.

To travel 22 miles using .47 gallons you would need to get (22 miles)/(.47 gallons) = 47 miles per gallon.

This seems to make sense to me.