Answer
$1.4 \times 10^{11}$ US gallons
Work Step by Step
There are about 210 million licensed drivers in the United States. On average, each driver drives around 16,000 miles annually, and the average vehicle has a mile per gallon rating of 24.
This means that $3.36 \times 10^{12}$ miles are driven each year by Americans. Therefore, the total amount of gallons consumed annually is represented by $x$ in the proportion $\frac{3.36 \times 10^{12} miles}{x}$ $=$ $\frac{24 miles}{1 gallon}$.
Next, you must solve for $x$.
$\frac{3.36 \times 10^{12} miles}{x}$ $=$ ${24 mpg}$.
${3.36 \times 10^{12} miles}$ $=$ ${24 mpg} \times {x}$
$\frac{{3.36 \times 10^{12} miles}}{25 mpg}$ $=$ ${x}$
$x = 1.4 \times 10^{11}$ US gallons