Question

An airplane that flies from New York City to Los Angeles for Speedy State Airlines flies at an average speed of

450 mph and uses an average of 0.5 gal of fuel every second.
1. Determine the plane's fuel efficiency, in miles per gallon, by first converting the plane's speed into miles per
second.

Answer 1

0.25 mpg

Explanation:

Given the speed of an airplane is 450 mph and its fuel consumption is 0.5 gal/second, you want the fuel efficiency.

Unit conversion

It is convenient to use the same unit of time in each of the given rates. The speed in miles per second is ..

(450 mi/h) × (1 h)/(3600 s) = 1/8 mi/s

Efficiency

The fuel efficiency is found by dividing the distance traveled in one second by the fuel used in one second:

η = (1/8 mi)/(0.5 gal) = 1/(8×0.25) mi/gal = 1/4 mi/gal

The plane's fuel efficiency is 1/4 mile per gallon.