Labor

$($workers per day$)$ Output

$($units per day$)$

$00$

$110$

$215$

$318$

$420$

$521$

Cindy's Sweaters' production function is shown in the above table. Cindy rents two knitting machines for $$30$ a day each and hires workers at a wage rate of $$40$ a day. What is the marginal cost of the $19$th sweater?

Group of answer choices

$$8\mathrm{.}00$

$$40\mathrm{.}00$

$$20\mathrm{.}00$

$$10\mathrm{.}00$