i need help solving this

A three-year project has an initial fixed asset investment of $200,000, an initial NWC investment of $50,000 and an annual OCF of $70,000. The fixed asset is fully depreciated straight-line over the life of the project. At the end of the project, it will be worthless. The required return is 10% and tax rate is 20% (a) What is the project's NPV? (6 pts) (b) The initial fixed asset investment and annual OCF are accurate within +10%, what are the fixed asset investment and annual OCF would you use for the worst case and best case scenarios? (4 pts)