Answer:
50%
Step-by-step explanation:
The formula and the computation of the contribution margin ratio is shown below:
Contribution margin ratio = (Contribution margin per unit) ÷ (selling price per unit) × 100
where,
Contribution margin per unit = Selling price per unit - Variable expense per unit
= $40 per unit - $20 per unit
= $20 per unit
So, the CM ratio is
= ($20 per unit) ÷ ($40 per unit) × 100
= 50%