Whirly Corporation$$s contribution format income statement for the most recent month is shown below:

Total Per Unit

Sales $(7,400$ units$)$ $ $259,000$ $ $35\mathrm{.}00$

Variable expenses $133,20018\mathrm{.}00$

Contribution margin $125,800$ $ $17\mathrm{.}00$

Fixed expenses $54,400$

Net operating income $ $71,400$

Required:

$($Consider each case independently$)$:

What would be the revised net operating income per month if the sales volume increases by $80$ units?