Scott’s Scooters Ltd. manufactures three different products, Models A, B, and C. The below per-unit data apply:

	Model A	Model B	Model C
Selling price	$110	$90	$50
Direct materials	70	40	20
Direct labour ($40/hour)	20	20	10
Variable costs ($60/machine hour)	6	10	4
Fixed manufacturing costs	10	10	10

a. If there is excess machine capacity, additional units of which model(s) should be produced first to maximize profit?

b. If there are a limited number of direct labour hours available and demand exceeds the total direct labour hours available, in what order should the models be produced to maximize total contribution margin?