Insiteful Instruments produces two models of binoculars. Information for each model is as follows:

	Model 100								Model 101
Sales price per unit					$	200							$	215
Costs and expenses per unit:
Direct materials	$	51							$	38
Direct labor		33								30
Manufacturing overhead (applied at the rate of $18 per machine-hour, 1/3 of which is fixed and 2/3 variable)		36								72
Variable selling expenses		30								15
Total costs and expenses per unit						150								155
Profit per unit					$	50							$	60
Machine-hours required to produce one unit						2								4

Total manufacturing overhead amounts to $180,000 per month, one-third of which is fixed. The demand for either product is sufficient to keep the plant operating at full capacity (10,000 machine-hours per month). Assume that only one product is to be produced in the future.

a. Prepare a schedule showing the contribution margin per machine-hour for each product.

b. Which of the two products should be discontinued?