Car A: 24.8 Miles per gallon. Car B: 21 Miles per gallon Car C: 18.75 Miles per gallon
Car A is the answer. Make sure when you are putting work you multiply each number at the start of this answer with 0.62. That'll be how many Kilometers per gallon. Just divide the amount of Miles by the gallons for unit rate.
I know yours is an equation which is why I did not go any further because this is the standard form you are looking for. I would rewrite mine to get my hyperbola standard form. However the one I have provided is the form you need where mine would be.