please explain how to solve each question and what formuals to input in excel

H. 1 If you require a 20% return on your investment, what is the most could you pay at the beginning of this year for each of the following cash flow streams? (Do not use dated cash flows on this problem.) 4 Stream A: $1000 at the end of this and the following two years. 5 Answer: 10 Stream B: $1000 at the beginning of this and the following two years. 11 Answer: 12 13 14 15 16 17 Stream C: $1000 at the middle of this and the following two years. 18 Answer: 19 20 21 22 23 24