If an automobile is able to travel 400 km on 47.2 l of gasoline, what is the gas mileage in miles per gallon?

Distance traveled = 400 km

Volume of gas = 47.2 L

Note that

1 km = 0.62137 mi, or 1 mi = 1.609 km

1 L = 0.264 gal (US)

Therefore

400 km = (400 km) * (0.62137 mi/km) = 248.548 mi

47.2 L = (47.2 L) * (0.264 gal/L) = 12.4608 gal

The gas mileage is

(248.548 mi) / (12.4608 gal) = 19.95 mi/gal

Answer: 20.0 miles per gallon (nearest tenth)