Prepare a differential analysis. If an amount is zero, enter "0". If required, use a minus sign to indicate a loss. Should the machine be replaced? a. Compute the contribution margin per hour per cake. If required, round your answers to two decimal places. Chocolate cake Birthday cake Specialty cake b. Determine which cakes the company should try to sell more of first, second, and then last. 1st: 2nd: 3rd