A Reboiler costs 90,000RO with a life of 6 years and has no salvage value. It needs an annual maintenance expenditure of 1200RO for cleaning the tube and shell arrangement. The interest rate is 12%. Calculate the following: Present worth at zero time of the annual maintenance ii) Future worth of annual maintenance for each year of operation iii) Calculate the depreciation and asset value at the end of 4th year using straight line depreciation method