For x1= 120$, x2= 9%

I need full detailed written steps please do not use excel or any other tables.

Question(4): A power plant is being considered in the dead sea location. For an initial investment of $X1 million, annual net revenues are estimated to be $15 million in years 1-5 and $20 million in years 6-20. Assume no residual market value for the plant a. What is the simple payback period for the plant? b. What is the discounted payback period when the MARR is x2% per year? c. Using an equivalency technique (FW, PW, or AW), MARR is x2% per year, would you recommend investing in this project