I need help finishing this problem. I was able to calculate until the after tax cash flow but I need help finding the NPW and the EAUW. I also need help in explaining if the company should or should not build the substation using the MARR

A telephone company is considering building a new automated switching distribution substation with a useful life of 20 years to support new suburban developments. The substation is located in a state in which the combined tax rate is 40%, and the telephone company uses a 15% real interest MARR to assess capital investment projects. Estimated real dollar revenues and costs are as follows: Category Building initial cost Building salvage cost Equipment initial cost Equipment salvage value 29,000 Annual revenues Revenue arithmetic gradient S 20,000 years 2 to 5 Annual revenues Amount S1,157,000 S 250,000 S 575,000 S 650,000 year 1 750,000 years 6 to 20 185,000 first 10 years S 230,000, years 11 to 15 S 275,000, years 16 to 20 S Annual operating expenses $ The substation will be put into service on the first day of the telephone company's fiscal year. Using MACRS depreciation, what will be the telephone company's after tax equivalent uniform annual worth for the substation