The fuel efficiency for a certain midsize car is given by

E(v) = −0.018v^2 + 1.440v + 3.9 where E(v)is the fuel efficiency in miles per gallon for a car traveling v miles per hour.
(a) What speed will yield the maximum fuel efficiency? Round to the nearest mile per hour.
1 mph

(b) What is the maximum fuel efficiency for this car? Round to the nearest mile per gallon.
2 mpg

1 answer

find the derivative, set it equal to zero and solve.