please include formula and working, thank you.

Problem 3 (8 marks) Consider the following cash flows: Period 1 2 3 4 Cash Flow 5,000 3,000 2,000 4,000 a) If the interest rate is 9%, what is the present value of the cash flow stream if the cash flows occur at the end of the period? (2 marks) b) If the interest rate is 9%, what is the present value of the cash flow stream if the cash flows occur at the beginning of the period? (2 marks) c) If the interest rate is 9%, what is the future value of the cash flow stream if the cash flows occur at the end of the period? (2 marks) d) If the interest rate is 9%, what is the future value of the cash flow stream if the cash flows occur at the beginning of the period? (2 marks)