Problema Solution

The United States is about the only country left that uses the units feet, miles, and gallons. You see some car SPECIFICATIONS in a magazine that give fuel efficiency as 20 kilometers per kilogram of fuel. Given that a MILE is 1.609 km, a gallon is 3.785 liters, and if a liter of gasoline has a mass of 0.729 kg, what is the car's fuel efficiency in miles per gallon?

Answer provided by our tutors

we need to convert km to miles:


1 mi = 1.609 km


1 km = (1/1.609) mi


and convert kg to gal:


1 l = 0.729 kg


1 kg = 1/0.729 l


1 gal = 3.785 l


1 l = 1/3.785 gal


1 kg = (1/0.729)(1/3.785) gal


now we have


20 km/kg = 20*(1/1.609)/((1/0.729)(1/3.785)) miles per gal


20 km/kg = 34.3 mi/gal


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20 kilometers per kilogram of fuel is equal to 34.3 miles per gallon of fuel.