Answer:
Sadie's family car is more fuel efficient.
Step-by-step explanation:
Given;
Sadie's family car rating, S = 42 miles per gallon
Nanette's family car rating, N = 6 liters per 100 km
Sadie's family car rating, in liters per 100 km
[tex]= \frac{42 \ miles}{gallon} *\frac{1.609 \ km}{1 \ mile}*\frac{1 \ gallon}{3.79 \ liters} \\\\ = (\frac{42*1.609}{3.79} )\frac{km}{liter}\\\\ = (\frac{3.79}{42*1.609} )\frac{liter}{km}\\\\=(\frac{3.79}{42*1.609} )(\frac{100}{100}) \frac{liter}{km}\\\\= (\frac{3.79*100}{42*1.609} )(\frac{1}{100}) \frac{liter}{km}\\\\= (\frac{3.79*100}{42*1.609} ) \frac{liter}{100\ km}\\\\= 5.61 (\frac{liter}{100\ km})\\\\= \frac{5.61 \ liters}{100 \ km}[/tex]
Also, Nanette's family car rating, in liters per 100 km = 6 liters / 100km.
Thus, Sadie's family car uses lesser fuel, because of this Sadie's family car is more fuel efficient.