Math help

[Quiky One]

How would you set up an equation to see how many miles you would have to drive to break even on MPG improvement mods.

Say gas is $3.00 and you currently get 18 MPG. After $2k in mods you get 20. How would you set that up?

Thanks Jason

 

[salvageV6]

I didn't really set up an equation but just looked at the facts in this case.

After 9 gallons of gas you get an extra 18 miles with the mods.

Therefore you save $3 at that point one gallon of gas savings for the 18 miles using the old numbers.

Trying to save $2000 will take 2000/3= 666.66666666 savings in miles and gas gallons.

Therefore you multiply your 18 miles times that number to get:

12000 miles.

You probably could set up a ratio or proportion to do it also.

 

[TURBOTWIN2]

Silly decimal points! Don't you hate 'em? Actually I get 120,000 miles for break even point.
Cost per mile at 18 mpg at $3.00/gallon, divided by 18 mpg = 16.667 cents per mile or .1667.
Cost per mile at 20 mpg at $3.00/gallon, divided by 20 mpg = 15 cents per mile or .15.
So, .1667 minus .15 = .01667 cents per mile savings or .01667. 1 and 2/3 cents per mile savings.
$2000.00 divided by .01667 is 120,000 miles to break even.
Every 60 miles you drive would save you one dollar. 60 (miles per 1 dollar of savings) times 2000 (dollars worth of mods) is 120,000 (miles to break even).
If gas is cheaper, it would take longer to recoup, more expensive, shorter time frame. HTH.

 

[Quiky One]

Thanks!

Jason