Use the present value table in Appendix A and Appendix B to compute the NPV of each of the following cash inflows: a$.$ $$21250$ received at the end of $15$ years. The discount rate is $5$ percent. b$.$ $$6320$ received at the end of four years and $$12750$ received at the end of eight years. The discount rate is $7$ percent. c$.$ $$1440$ received annually at the end of each of the next seven years. The discount rate is $6$ percent. d$.$ $$45750$ received annually at the end of each of each of the next three years and $$82,000$ received at the end of the fourth year. The discount rate is $6$

percent.