4. Bob's Textile Company sells shirts for men and boys. The average selling price and variable cost for each product are as follows: Men's Boys Selling price $28.50 $24 Variable cost $19.00 $16 Total fixed costs $45,000 Required: 20 POINTS Assume the sales mix is 2 boy's shirts for each men's shirt: a. What is the weighted revenue per unit of composite average product, the weighted average variable cost, and the weighted contribution margin per unit of average product? b. What is the break-even point in units for each type of shirt? c. What is the operating income, assuming sales total 9,000 shirts