This model can be used to predict the fuel consumption of a car, y y\,y miles per gallon, for a car travelling at x x\,x miles per hour.
y=55−0.015(x−50)2 y = 55 - 0.015(x - 50)^2 y=55−0.015(x−50)2Calculate the fuel consumption, in miles per gallon, of a car travelling at 70 miles per hour.
Deduce the speed at which the car has the greatest fuel efficiency.
State, giving reasons, the limitation on the values of xxx
