Tirri Corporation has provided the following information:

	Cost per Unit			Cost per Period
Direct materials	$	7.50
Direct labor	$	3.85
Variable manufacturing overhead	$	1.55
Fixed manufacturing overhead				$	24,400
Sales commissions	$	1.05
Variable administrative expense	$	0.60
Fixed selling and administrative expense				$	8,800

If the selling price is $28.10 per unit, the contribution margin per unit sold is closest to: