math question: best rebate option (per litre or km)?

[scrubbyfish]

I can apply for a fuel tax rebate.
I can apply for a refund based on litres, at $0.015 per litre, OR
I can apply for a refund based on kilometres, at $0.0015 per kilometre.

My car seems to cost 13 cents in fuel per km.
I seem to drive about 13000 kms per year.

Which is the better rebate? (Is more info needed?)

[deborah]

How many litres/100km does your car do?

[MDM]

The rebate numbers are equal if your car gets 10 kilometres per liter  (10 kpl = 0.015 $/l / .0015 $/km).

If your fuel efficiency is worse (<10 kpl), go for the refund based on litres because you will be buying more litres per kilometer.

If your fuel efficiency is better (>10 kpl), go for the refund based on kilometres because you will be driving more kilometres per litre.
 

[scrubbyfish]

Okay, I did a search for the info I was given in a different thread I started a while back (to figure out my cost per km). I found this from SoftwareGoddess:

...car does 28 MPG City / 35 Hwy.
Assuming that MPG is miles per *imperial* gallon:
28 MPG * 1.61 km per mile / 4.55 liters per imperial gallon = 9.9 km per liter or about 10.1 liters per 100 km.
So, for every 10 km of city driving, you use about 1 liter of gas.
At $1.268 per liter, it's about $0.12 per km in the city.

So, yes about 10kms per litre. So, according to what you're saying, MDM, in my case it's equal which I apply for, is that right? And if I suspect I might use more fuel than that per km (winter tires year round, etc), I should apply for the rebate based on litres, yes?

[deborah]

Yes. However, why don't you find out how much you are doing? Fill up your car and record the km reading x, drive then fill it up to the same point and record the new km reading y and the litres z. Km done = y-x. Litres/km  = z/(y-x)