Question

Estimate the number of gallons of gasoline consumed by the total of all automobile drivers in the U.S., per year. Suppose that there are about 3 × 10^8 people in the United States, approximately half of the them have cars, each car drives an average of 12,000 mi per year, and consumes a gallon of gasoline for each 20 mi?

Answer 1

3 x 108 is roughly 300 people. Half of them have cars. Half of 300 = 150. 150 x 12000 = 1,800,000 miles driven. Each car gets 20mpg. Solve for the # of gallons consumed.

Answer 2

`G = 9 * 10^(10) gallons`

Step-by-step explanation:

Total number of people in US is
`N_p = 3 * 10^8`

Only half of them have cars. So, Number of cars in US

`N_C = (N_p)/(2) \\\\N_C = (3 * 10^8)/(2) \\\\N_C = 1.5 * 10^8`

Each cars drives 12000 miles, so total distance travelled by all of these cars combined

`D = N_C * 12000\\\\D = 1.5 * 10^8 * 12000\\\\D = 1.8 * 10^(12) miles`

To travel 20 miles, we need 1 gallon of gasoline

Amount of gasoline required to travel one mile is
`(1)/(20)` gallons

Amount of gasoline required to cover the distance 'D'.

`G = D * (1)/(20) \\\\G = 1.8 * 10^(12) * (1)/(20) \\\\G = 9 * 10^(10) gallons`

Amount of gasoline required to cover the distance 'D'.

`G = D * (1)/(20) \\\\G = 1.8 * 10^(12) * (1)/(20) \\\\G = 9 * 10^(10) gallons`