Use this income statement to answer the questions that follow. Sales ($50 per unit) $5,350 Less: Cost of goods sold ($32 per unit) 3,424 Gross margin 1,926 Less operating expenses: Salaries $7195 Advertising 390 Shipping ($3 per unit) 321 1,506 Operating Income $ 420 (a) What is the variable cost per unit? Variable cost per unit $