Archive for June, 2019

Real World Graduation, Question 85: Energy Efficiency

RealWorldGraduation_Question_85_Energy_Efficiency   <– PDF

Four people commute to work in the following ways. Person A drives a very fuel efficient car that gets 50 miles to the gallon; he drives alone 75 miles each way to work.  Person B drives alone in an old inefficient pickup truck that gets 12 miles to the gallon; he drives 12 miles each way.  Person C drives a car that gets 25 miles to the gallon.  He drives it alone 5 miles each way to a light-rail station.  There he gets on public light-speed rail; each train consists of 4 cars, and each car holds up to 30 people.  The train is electric, but its energy usage is the equivalent of 2 miles to the gallon, and his commute on the train is 20 miles each way.  Person D takes the city bus 16 miles each way; the bus gets 4 miles per gallon, and holds up to 60 people.  Assume that all the mileages are calibrated to the same blend of gasoline (although they may actually use different fuels).  Which person uses the most efficient means in of energy expenditure in the course of getting back and forth to work?

a) Person A

b) Person B

c) Person C

d) Person D

e) Indeterminate exactly, but it is either Person A or D

(The answer is on p. 2 of the PDF.)

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