5- A defined benefit retirement plan offers to pay $6,000 per year for 20 years and increase the annual payment by 2% each year. What is the present value at retirement if the discount rate is 7 percent? 6- an investment offers a perpetual cash flow of $500 every year. The return you require on such an investment is 8 percent. What is the value of this investment? 7- Suppose that we are looking at a investment payout over a 20-year period. The first payment, made one year from now, will be $200,000. Every year thereafter, the payment will grow by 5 percent. What's the present value if the appropriate discount rate is 11 percent