(Present value of an annuity) What is the present value of the following annuities? a. $2,400 a year for 9 years discounted back to the present at 9 percent. b. $80 a year for 3 years discounted back to the present at 7 percent. c. $250 a year for 13 years discounted back to the present at 12 percent. d. $550 a year for 6 years discounted back to the present at 5 percent. a. What is the present value of $2,400 a year for 9 years discounted back to the present at 9 percent? (Round to the nearest cent.)