Answer:
120 cars
Step-by-step explanation:
The given function is
[tex]C(x)=0.5x^2-120x+21,481[/tex]
and its parent function would be
[tex]f(x)=ax^2+bx+c[/tex]
So,
[tex]a=0.5[/tex]
[tex]b = -120[/tex]
and
[tex]c = 21,481[/tex]
The minimum cost would be found using:
[tex]x = -\frac{b}{2a}[/tex]
So just input a and b into the function:
[tex]x= -\frac{-120}{2(0.5)}[/tex]
[tex]x=-\frac{-120}{1}[/tex]
[tex]x = 120[/tex]
Therefore there must be 120 cars made to minimize the cost.