Date:         Tue, 9 Sep 2003 23:57:54 -0400
Reply-To:     "Daniel L. Katz" <katzd54@YAHOO.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         "Daniel L. Katz" <katzd54@YAHOO.COM>
Subject:      Re: better gas mileage

well, just in case this wasn't a joke, note that the problem at hand isn't
simply a math problem. instead, the arithmetic relates to something
physical, and units are attached to the numbers. whence:

mpg = miles driven/gallons of fuel used = 198 mi/11 gal = 18 mi/gal.

further, we usually have some sense of the expected magnitude for the
result of a physical calculation, and the original sender was obviously
suspicious that 35 mpg wasn't reasonable.

as another example, suppose we wanted the average speed over the 198
miles, and knew that the trip took 4 hours and 15 minutes = 4.25 hours.
whence, mph = 198 mi/4.25 h = 46.6 mi/h. note that the entire time was
converted to hours before doing the actual mpg calculation.

keeping the units straight and having some idea beforehand as to the
likely magnitude of the result are powerful tools in the business of
physical calculations.


On Tue, 9 Sep 2003 22:20:54 -0400, Daniel L. Katz <katzd54@YAHOO.COM>
wrote:

>surely you're joking.
>
>
>On Tue, 9 Sep 2003 15:18:03 +0000, Joseph Fortino <fortinoj@SPEAKEASY.NET>
>wrote:
>
>>hello all,
>>
>>seems i'm getting about 30+ mpg, does this sound right after replacing
>the ECU and some other tune-up parts i'm getting way better mileage.
>>
>>trip meter read 198 miles
>>took 11 gal at station
>>16 gal tank right did the math and came up with 35mpg
>>
>>* is my math wrong * ;)
>>
>>Thanks,
>>Joe