Based on company records of similar equipment, a consulting civil engineer at Aerospatiale estimated for maintenance a presently owned, highly accurate steel rivet inserter whose purchase price when new is 85000$ and the maintenance cost is 11000$, 13000$, 16000$, 20000$ respectively. After fourth year the maintenance cost is 4500 N where N = 5,6,7,8 n-in year if the resale value decreased by 8% of purchase prince each year what is replacement policy