A firm sells three products:

Product 1: $15 sales price per unit; $9 variable cost per unit. Product 2: $11 sales price per unit; $8 variable cost per unit. Product 3: $22 sales price per unit; $17 variable cost per unit.

In a typical year, 25% of sales units are Product 1, while 25% of sales units Product 2, and 50% of sales units are Product 3.

What is the firm's composite unit CM (just contribution margin for one composite unit)?

Simplify the sales mix so there is one unit of Product 1 per composite unit.