Hi-Tech Incorporated produces two different products with the following monthly data: Cell GPS Total Selling price per unit 100 400 Variable cost per unit 40 240 Expected unit sales 21,000 9,000 30,000 Sales mix 70% 30% 100% Fixed costs $ 1,800,000 Assume the sales mix remains the same at all levels of sales. Required: a. Calculate the weighted average contribution margin per unit. b. How many units in total must be sold to break even? c. How many units of each product must be sold to break even? d. How many units in total must be sold to earn a monthly profit of $180,000? e. How many units of each product must be sold to earn a monthly profit of $180,000