please show all work/formulas not in excel. will upvote thank you.

Calculate the time present value of the following two streams of cash flows (CF). Assume 5% interest rate per period. CFO) means the cash flow at period A) CEO) - $10, CF(t)-S5, CF(2) 510. Starting from period 3 (including period 3), CF is $20 forever. 1 B) CROS0. Starting from period 1 (including period 1). CF is $10 forever, except for period 10, when the CE(10) - $20