(Present value?) What is the present value of the following future? amounts? a. ?$ 800 to be received 10 years from now discounted back to the present at 11 percent. b. ?$ 300 to be received 6 years from now discounted back to the present at 9 percent. c. ?$1,200 to be received 11 years from now discounted back to the present at 5 percent. d. ?$ 1,250 to be received 5 years from now discounted back to the present at 17 percent