Chapter 20 - Weighted Average CM Unit, CM Ratio, and Contribution Margin Per Unit of Limited Resource 3. Contribution margin per unit of Limited Resource a. Data for Charlie Company is shown below. Find the Contribution Margin per Unit of Limited Resource Contribution Limited Resource Contribution Product (Machine Hours Margin per unit of Margin Per Unit Required) limited resource Product A $125 .75 Product B $65 25 I b. *If total machine hours are limited to 1200, what is total contribution margin if they produce only the most profitable product