Answer: [tex]\$18,629[/tex]
Step-by-step explanation:
Given
The unit cost is given by
[tex]C(x)=0.6x^2-168x+30,389[/tex]
find the derivative of the unit cost and equate it to zero to obtain the minimum value
[tex]C'(x)=0.6\times 2x-168\\\Rightarrow 0.6\times 2x-168=0\\\Rightarrow 1.2x=168\\\\\Rightarrow x=\dfrac{168}{1.2}\\\\\Rightarrow x=140[/tex]
Substitute 140 for [tex]x[/tex] in the cost function, we get
[tex]C(140)=0.6[140]^2-168(140)+30,389\\C(140)=11,760-23,520+30,389\\C(140)=\$18,629[/tex]