Required: a. Assume that only one product is being sold in each of the following four case situations: Unit sold Sales Variable expenses Fixed expenses Operating income (loss) Contribution margin per unit Case #1 Case #2 Case #3 Case #4 16,200 10,800 6,480 $ 194,400 $ 108,000 $ 324,000 129,600 75,600 54,000 34,560 108,000 $ $ 8,640 $ 10 S 12,960 $ (10,800) 13 b. Assume that more than one product is being sold in each of the following four case situations: (Enter "Contribution margin ratio" in percent. Round your final answers to the nearest whole dollar amount.) Case #1 Case #2 Case #3 Case #4 Sales $ 508,000 $ 408,000 $ Variable expenses 265,200 608,000 425,600 Fixed expenses 102,000 132,400 Operating income (loss) $ 7,400 $ 22,400 $ (4,200) Average contribution margin (percentage) 20% 60%