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 20,100 13,400 8,040 S 241,200 $ 134,000 $ 402,000 160,800 93,800 67,000 42,880 134,000 $ $ 10,720 $ 10 $ 16.080 $ 13 (13,400) 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 $ 534,000 $434,000 $ 634,000 Variable expenses Fixed expenses 282,100 108,500 443,800 140,200 Operating income (loss) $ 8,700 $ 30,200 $ (4,000) Average contribution margin (percentage) 20% 60%