The area of a region under a curve is greater than the area of an inscribed rectangle and less than the area of a circumscribed rectangle. Intuitively, we understand that somewhere \"between\" the inscribed and circumscribed rectangles there is a rectangle whose area is precisely equal to the area of the region under the curve: ba (x)dx = f (c)(b a) The average value of a function on the interval [a; b] is determined by Average value = 1 b a f (x)dx ba The eciency e (in %) of an automobile engine is given by e = 0.768s - 0.00004s^3 Where \"s\" is the speed (in km/h) of the car. Find the average eciency with respect to the speed for s = 3{{a]} km/h to s = 8 {[d]} km/h. Round the answer to one decimal place. {[a]} = 2, then s = 32 km/h, and if {[d]} = 4, then 8{[d]} = 84 km/h