
Bradford T. answered 09/29/21
Retired Engineer / Upper level math instructor
The revenue is:
R(x) = 400x-0.25x2
This is the equation for a parabola. The maximum can be found at the vertex of the parabola using the formula:
x=-b/2a from the parabolic equation ax2+bx+c where a=-0.25, b=400 for this case
x = -400/(2(-0.25)) = 400/0.5 = 800
R(800) = 400(800)-8002/4 = 240000 - 640000/4 = $80000