Which function is an example of exponential decay?
1 answer:
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Answer:
15 billions gallons are saved a year with the fuel efficiency increased to 28 mi/gal.
Step-by-step explanation:
This problem can be solved by the use of rules of three.
The first step is find how many gallons are used with the efficiency of 21mi/gal:
1gal are used for 21 miles. How many gal are needed for 12,600 miles. So
1 gal - 21 miles
x gal - 12,600 miles
21x = 12,600
x = 600 gallons
Each passenger uses 600 gallons a year.
There are 100 million passengers a year, so:
1 passenger - 600 gallons
100,000,000 passengers - x gallons
x = 600*100,000,000
x = 60,000,000,000
With the efficiency at 21mi/gal, 60 billion gallons are used a year.
Now with the efficiency at 28 mi/gal
Same logic as above:
1gal - 28 miles
x gal - 12,600 miles
28x = 12,600
x = 450 gallons
Each passenger uses 450 gallons a year of gasoline.
There are 100 million passengers a year, so:
1 passenger - 450 gallons
100,000,000 passengers - x gallons
x = 450*100,000,000
x = 45,000,000,000
With the efficiency at 28mi/gal, 45 billion gallons are used a year. It means that 60 billion - 45 billion = 15 billions gallons are saved a year with the fuel efficiency increased to 28 mi/gal.