Speedy Quadcopters plans to sell a standard quadcopter (toy drone) for $70 and a deluxe quadcopter for $100. Speedy purchases the standard quadcopter for $50 and the deluxe quadcopter for $80. Management expects to sell two deluxe quadcopters for every three standard quadcopters. The company's monthly fixed expenses are $16,000. How many of each type of quadcopter must Speedy sell monthly to breakeven? To earn $13,000? = First identify the formula to compute the sales in units at various levels of operating income using the contribution margin approach. (Abbreviations used: Avg. = average, and CM = contribution margin.) ( Fixed expenses + Operating income ): Weighed-avg. CM per unit = Breakeven sales in units Next compute the weighted average contribution margin per unit. First identify the formula labels, then complete the calculations step by step. Standard Sale price per unit Deduct: Variable expense per unit Contribution margin per unit Sales mix in units Contribution margin Weighted average contribution margin per unit