91Ó°ÊÓ

Here,

For every three individuals, there are two automobiles.

Each automobile travels 12,000 miles each year on average.

The typical automobile achieves a mileage of 15 miles per gallon.

$P=$ Number of population

As a result, the average automobile consumes $12000/15=800$ gallons of gas every year.

1 gallon $=3.78541$ litres is the gallon to litre conversion factor.

As a result, the typical automobile consumes $3028.328$ gallons of gas per year $(800×3.78541)$

In 2017, the United States had a population of $325.7$ million people.

Because there are two automobiles for every three persons, the total number of cars is $\frac{2}{3}×325.7$ million $=217.1333333$ million.

If each automobile consumes $3028.328$ litres of gas per year on average, the total annual gas consumption would be $3028.328×217.13333333$ million$=657,550.9531$ million litres.

That's an estimate based on the population of the United States, the car-to-person ratio, the average number of miles travelled per year, and the average gas consumption at the time the study was conducted.

To put it another way, it will alter from year to year as the various elements change. The amount of litres per gallon is the only item that will remain consistent. $=325.7×{10}^6×\frac{2\text{cars}}{3\text{people}}×\frac{10000\text{mile}/\text{year}}{1\text{car}}×\frac{1\text{gallon}}{20\text{mile}}×\frac{1\text{year}}{365\text{days}}$

Therfore it can be said that $3×{10}^8$ gallons /day , gasoline are used by people in the United States