The fuel economy of a car, measured in miles per gallon, is modeled by the function ƒ (s) = - 0.009s2 + 0.699s + 12 where s represents the speed of the car, measured in miles per hour. What's the fuel economy of the car when it travels at an average of 20 miles an hour?

25.62 = -.009 (20*2) +.699 (20) + 12

22.38 miles per gallon is the fuel economy of the car.

Step-by-step explanation:

The fuel economy of the car is modeled by the function f (s) = - 0.009s² + 0.699s + 12

Where s = speed of the car measured in miles per hour.

Now we have to find the fuel economy of the car when it travels at an average of 20 miles an hour.

Now we plug in the value of s = 20 miles per hour in the given function

f (20) = - 0.009 (20) ² + 0.699 (20) + 12

= - 3.6 + 13.98 + 12

= 22.38 miles per gallon

Therefore, at the speed of 20 miles and hour fuel economy of the car will be 22.38 miles per gallon.