Formula please

You believe you have discovered a new medical device. You anticipate it will take additional time to get the device fully operational. fun elinical trials, obtain FDA approval, and sell to a buyer for $250,000. Assume a discount rate of 7% compounded annually. What is the value today of discovering the medical device. assuming you sell it for $250,000 in (a) two years, (b) three years, or (c) four years? (EV of S1. PV of S1. EVA of S1, and PVA of S) (Use tables, Excel, or a financial calculator. Round your answers to 2 decimal places.)