Having trouble with the last 3. please help !!

i apologize. here is the diagram

8) You are currently paying $250 per month to lease your office phone equipment. You have three years left on a five-year lease. What would have been an equivalent purchase price two years ago? The effective interest rate per month is 1%. 9) An investor holds a time payment purchase contract on some machine tools. The contract calls for the payment of $140 at the end of each month for a five-year period. The first payment is due in one month. He offers to sell you the contract for $6800 cash today. If you otherwise can make 1% per month on your money, would you accept or reject this offer. 10) Bonus: Find the present net equivalent value (present value) of the diagram in problem 5. (C0900 3 h br 15