We have two vehicles
A: old truck that does 17 mpg (13.84 l/100km)
B: old car that does 47 mpg (5.00 l/100km)
We are looking to replace one of these vehicles with a new one (of the same size)
C: new truck 19 mpg (12.38l/100km)
D: new car 61 mpg (3.85l/100km)
So which vehicle should we replace to save fuel? The old truck or the old car to end up with.
- AD (old truck + new car)
- BC (new truck + old car)
Read bellow once you have your anwser:
The way I solved this:
A: Old truck 13.84 l/100km + D: new car 3.85 l/100km = 17.69 l/100km,
B: New truck 12.38 l/100km + C: old car 5.00 l/100km = 17.39 l/100km
Combination BC uses less fuel.(0.31l less). Now using mpg:
17mpg + 61mpg = 78mpg
19mpg + 47mpg = 66mpg
Making the combination AD a better choice.
Why the exact opposite answer? What am I missing here?