A company is considering replacing an old piece of machinery, which cost $400,000 and has $175,000 of accumulated depreciation to date, with a new machine that has a purchase price of $550,000. The old machine could be sold for $250,000. The annual variable production costs associated with the old machine are estimated to be $72,500 per year for eight years. The annual variable production costs for the new machine are estimated to be $24,000 per year for eight years. 

a. Prepare a differential analysis dated May 29 to determine whether to continue with (Alternative 1) or replace (Alternative 2) the old machine.

b. What is the sunk cost in this situation?