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: b. Assume that more than one product is being sold in each of the following four case situations: (Enter "Contribution percent. Round your final answers to the nearest whole dollar amount.)