Final answer:
To find the total number of gallons of gas needed to drive a certain number of miles in the city and on the highway, you need to calculate the separate amounts for each type of driving and then add them together. The answer is A) x.
Step-by-step explanation:
To find the total number of gallons of gas needed, we need to calculate the separate amounts for city driving and highway driving and then add them together. Let's use the variable x to represent the miles driven.
For city driving, the car averages 18 miles per gallon. So for 6x miles in the city, it would require 6x/18 gallons of gas.
For highway driving, the car averages 27 miles per gallon. So for 18x miles on the highway, it would require 18x/27 gallons of gas.
Adding these two amounts together, the total number of gallons of gas needed is (6x/18) + (18x/27). Simplifying this expression, we get (1/3)x + (2/3)x = (3/3)x = x.
Therefore, the answer is A) x.