Answer:
30.72 miles per gallon is the best approximate for the average gas mileage at a speed of 60 miles per hour
Explanation:
Given the equation:
,....[1]
where,
y is the average gas mileage (in miles per gallon)
x is the speed (in miles per hour)
We have to find the the average gas mileage at a speed of 60 miles per hour.
⇒
miles per hour.
Substitute in [1] we have;
⇒
⇒

Simplify:
y = 30.72 miles per gallon
Therefore, the best approximate for the average gas mileage at a speed of 60 miles per hour is, 30.72 miles per gallon