How to solve for contribution margin per unit?

Glocker Company makes three products in a single facility. These products have the following unit product costs:

	Product
	A			B			C
Direct materials	$	33.90		$	50.40		$	56.80
Direct labor	$	21.30		$	23.90		$	14.70
Variable manufacturing overhead	$	2.30		$	1.70		$	0.40
Fixed manufacturing overhead		6.40			4.00			4.60
Unit product cost		$63.90			$80.00			$76.50
Additional data concerning these products are listed below.
Mixing minutes per unit		1.10			0.70			0.20
Selling price per unit	$	69.00		$	91.40		$	84.90
Variable selling cost per unit	$	1.70		$	2.20		$	2.00
Monthly demand in units		3,100			4,400			2,400

The mixing machines are potentially the constraint in the production facility. A total of 6,870 minutes are available per month on these machines. Direct labor is a variable cost in this company.