Question 32405
m(x)= 20x-x^2 
m(x) represents a parabola, opens downward (because of negative sign in x^2)
The maximum will be attained at its vertex.
x-coordinate of the vertex of a parabola ax^2 + bx + c is -b/2a
-b/2a = -20/(-2 ) = 10
Answer: 10