18 - University Physics with Modern Physics

Question

How many gallons of gasoline are used in the United States in one day? Assume that there are two cars for every three people, that each car is driven an average of 10,000 miles per year, and that the average car gets 20 miles per gallon.

Step-by-Step Solution

Answer

$2.98\times {10}^8 gallons/day$ gasoline is used in the US.

Gallons of gasoline used in one year

Given data:

Each car is driven an average of 10000 miles per year.

The gasoline used by each car is 20 miles per gallon.

 Considering the population of US is 325.7 million people.

 There are two car for every three people, then the number of car in US will be,

 $$\begin{gathered} n=\frac{2}{3}\times 325.7 million \\ n\approx 218 million cars \end{gathered}$$ 

 The gasoline used by each car will be,

 $$\begin{gathered} m=\frac{10000 miles per year}{20 miles per gallon} \\ m= 500 gallons/year \end{gathered}$$

Calculation of usage of gasoline

The total gasoline use in one year will be,

 $$\begin{gathered} x=mn \\ x=500 gallons/year\times 218 millions/cars\times \frac{{10}^6}{1 million} \\ x=1.09\times {10}^{11} gallons/year \end{gathered}$$

 

The amount of gasoline required each day will be,

 $$\begin{gathered} x=1.09\times {10}^{11} gallons/year\times \frac{1 year}{365 days} \\ x=2.98\times {10}^8 gallons/day \end{gathered}$$

 

Thus, the number of gallons used in each day is $2.98\times {10}^8 gallons/day$  .