please do it by handwritten and by steps please

Question 1: Mohammad wants to open a jewellery shop. The price of diamonds is very volatile and the projected profits over the next five years are 100,000, 250,000, 10,000 , 200,000 and 50,000 respectively. After that profits will be a constant 150,000 per year for next 20 years at which time the shop closes. If 7% is the appropriate discount rate for the first five years and is 8% after that, what is the present value his profit/business