Investment Apprasial

Hi there, Im trying to do the mock and when it comes to section B i just cant get the NPV question right. Initial cost : 300,000 Scrap value : 20,000 Expected life 5 yrs Additional Revenue : 120,000 p.a Incremental costs : 30,000 p.a Cost of capital : 10% I know it is inflows minus the outflows then finding the rates within tables. Still cant get it to match ans. Could you help me with this? Thanks a million