 Rarely does a company sell just one product, so break-even becomes more complicated based on the sales mix. The sales mix is the relative percentage in which a company sells its products. You can see an example of a sales mix here on the slide. Sales mix is an important concept because rarely do different products have the same contribution margin. In order to determine break-even for multiple products, we need to determine the weighted average contribution margin. In doing so, our formulas get tweaked a little bit. We will divide fixed costs plus operating income by the weighted average unit contribution margin. In order to figure out the weighted average unit contribution margin, we need to do a couple of steps. First, let's multiply the product contribution margin times the sales mix. Once we add all of these amounts up, we have the total unit contribution margin. Then let's divide that total number of products sold to equal the weighted average contribution margin. So let's assume the following. Product A has a contribution margin of $20. Product B has a contribution margin of $10. And product C has a contribution margin of $5. Let's assume the sales mix is 60% A, 30% B, 10% C, and our fixed costs are $10,000. So first, we multiply the product contribution margin by the product mix. In this case, I used 10 units because that gives me 6 plus 3 plus 1 for a total of 10. So product A is 20 times 6. Product B is 10 times 3. And product C is 5 times 1. This gives us a total contribution margin of $155. Then we divide it by the 10 units and we get a weighted average contribution margin of $15.50. So break even based on the given sales mix is 645 units.