Why is it necessary to calculate a weighted-average contribution margin ratio for a multiproduct company when calculating

Question:

Why is it necessary to calculate a weighted-average ratio for a multiproduct company when calculating the break-even point for that company? Why can’t all of the products’ ratios just be added together and averaged?
Contribution Margin
Contribution margin is an important element of cost volume profit analysis that managers carry out to assess the maximum number of units that are required to be at the breakeven point. Contribution margin is the profit before fixed cost and taxes...