You have the following end of year cash flows:
Y0 = $400
Y1 = $300
Y2 = $200
Y3 = $100
Y4 = $0
Y5 = $0
Y6 = $0
Y7 = $500
Y8 = $500
Y9 = $500
Equate the following cash flows to equal cash flows in years 5,6,7,8 and 9. Let i = 8% per year. Use a uniform gradient factor in your solution.