Outflow at time 0: (300,000) Net inflow of 90,000 per year (120,000 – 30,000) for 5 years, so multiply 90,000 by the 5 year annuity discount factor at 10%. Inflow at time 5 of 20,000, so multiply 20,000 by the present value factor for 5 years at 10%.
(I assume that you have watched our free lectures on how to do the discounting?)