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 21,000 14,000 8,400 $ 252,000 $140,000 $ 420,000 168,000 98,000 70,000 44,800 140,000 $ $ 11,200 $ 10 $ 16,800 $ (14,000) 13 Sales 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 $540,000 $440,000 Case #2 Case #3 Case #4 $640,000 Variable expenses 286,000 448,000 Fixed expenses 110,000 142,000 Operating income (loss) $ 9,000 $ 32,000 $ (4,600) Average contribution margin (percentage) 20% 60%