Please help me to understand how to answer this question, step-by-step using a financial calculator.

You are operating an old machine that is expected to produce a cash inflow of $5,400 in each of the next three years before it fails. You can replace it now with a new machine that costs $24,000 but is much more efficient and will provide a cash flow of $12,000 a year for four years. Should you replace your equipment now? The discount rate is 16%.