Fill in the missing amounts in each of the eight case situations below. Each case is independent of the others. (Hint: One way to find the missing amounts would be to prepare a contribution format income statement for each case, enter the known data, and then compute the missing items.) 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 18,000 12,000 7,200 $ 216,000 $ 111,000 120,000 S 360,000 81,000 60,000 38,100 120,000 $ 9,600 $ 11,100 $ (12,000) $ 10 $ 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 Sales S 520,000 $ 420,000 $ Variable expenses 273,000 Case #4 620,000 434,000 Fixed expenses 105,000 136,000 Operating income (loss) S 8,000 $ Average contribution margin (percentage) 20% 26,000 $ 60% (4,800)