Shown here is an income statement in the traditional format for a firm with a sales volume of 7,800 units. Cost formulas also are shown: $34,100 23,060 $11,040 Revenues Cost of goods sold ($5,900 + $2.20/unit) Gross profit Operating expenses: Selling ($1,180 + $0.09/unit) Administration ($3,950 + $0.25/unit) Operating income 1,882 5,900 $ 3,258 Required: a. Prepare an income statement in the contribution margin format. b. Calculate the contribution margin per unit and the contribution margin ratio. c. Calculate the firm's operating income (or loss) if the volume changed from 7,800 units to 1. 11,700 units. 2. 3,900 units. d. Refer to your answer to part a for total revenues of $34,100. Calculate the firm's operating income (or loss) if unit selling price and variable expenses per unit do not change and total revenues 1. Increase by $10,500. 2. Decrease by $3,000