The monthly total cost function, in dollars, for producing x swim goggles is given by
$C(x) = 0.08x^2 - 9x + 475$
$0 \le x \le 130$
Below are the derivative of the cost function and the average cost function,
respectively.
$\bullet C'(x) = 0.16x - 9$
$\bullet \overline{C}(x) = 0.08x - 9 + \frac{475}{x}$
Using $C(x)$, $C'(x)$, or $\overline{C}(x)$ (there is only one correct function to use),
what are the average costs at a production level of 81 goggles per month? Round to
cents
$5.12
$3.34
$3.96
$2.88
$4.12
