Answer:
Weighted average unit contributIoN = $17
Explanation:
Weighted average contribution margin is applicable where a business sells more than one product in a constant mix or proportion. It gives an idea of how much is made on the average as contribution from th sale of a unit.
It is determined as follows
Step 1
Contribution per unit
Contribution per unit = selling price - unit variable cost
                     Sleek    Smooth    Potent
Selling price             30        50        70
Variable cost           (18)         (30)       (45)
Contribution  ($)         12          20       25
step 2
weighted average unit contribution
= (50%×12) +  (30%×20) + (20%×25)
= $17