You are considering investing in a security that will pay you ​$4000 in 25 years. a. If the appropriate discount rate is 9 percent​, what is the present value of this​ investment? b. Assume these investments sell for ​$1578 in return for which you receive ​$4 comma 000 in 25 years. What is the rate of return investors earn on this investment if they buy it for ​$1 578​?