$\"\"$

The car drives $\"\"$ miles a year and gets $\"\"$ miles per gallons.

The average cost of the fuel is $\"\"$ dollars per gallon.

$\"\"$ .

Annual cost of the fuel $\"\"$

Annual cost of the fuel $\"\"$ .

$\"\"$ .

Differentiate with on each side with respect to $\"\"$ .

$\"\"$

Complete the table.

\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \

The slope of the cost function is much steeper for $\"\"$ miles per gallon than $\"\"$ miles per gallon.

Hence it would be more benefit if the driver drives the car with $\"\"$ miles per gallon.

$\"\"$

Annual cost of the fuel is $\"\"$ .

\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \

It would be more benefit to drive the car with $\"\"$ miles per gallon.