please show work and explain

1) Refer to the following table of cash flows End of vear 0 12 S15,000 S15,000 S15,000 $15,000 Cash flow $15,000 What is the annual worth of these cash flows over 20 years when MARR-15% per year? 2) Refer to the following table of cash flows: End of vear Cash flow 12 $5,000 0 5,000 5,000 $5,000 What is the annual worth of these cash flows over 16 years when MARR-15% per year? 3) Refer to the following table of cash flows End of year Cash flow 0 $15,000 12 $5,000 $5,000 $5,000 S15,000 What is the annual worth of these cash flows over 20 years when MARR-15% per year