From Wikipedia, the free encyclopedia. Phototoxicity, also called photoirritation, is a chemically induced skin irritation, requiring light, that does not involve the immune system. It is a type of photosensitivity. The skin response resembles an exaggerated sunburn.
The contribution margin ratio is the difference between a company's sales and variable expenses, expressed as a percentage. The total margin generated by an entity represents the total earnings available to pay for fixed expenses and generate a profit.
Iversonâs contribution margin ratio is 60%, so if it wants to break even, it needs to either reduce its fixed expenses by $60,000 or increase its sales by $100,000 (calculated as $60,000 loss divided by 60% contribution margin ratio).o calculate the contribution margin ratio, divide the contribution margin by sales. The contribution margin is calculated by subtracting all variable costs from sales.