A company is operating an old machine that is expected to produce a cash inflow of $$5,000$ in each of the next $3$ years before it fails. It can be replaced now with a new machine cost $$20,000$ but is much more efficient and will provide a cash flow of $$10,000$ a year for $4$ years. What would you do$?$ What benefits and costs are there? Explain why you made these assumptions and considerations?