15. Problem 5.15 (Present Value of an Annuity) eBook Find the present values of these ordinary annuities. Discounting occurs once a year. Do not round intermediate calculations. Round your answers to the nearest cent. a. $1,000 per year for 12 years at 10%. b. $500 per year for 6 years at 5%. c. $800 per year for 6 years at 0%. d. Rework previous parts assuming they are annuities due. Present value of $1,000 per year for 12 years at 10%:$ Present value of $500 per year for 6 years at 5%: $ Present value of $800 per year for 6 years at 0%: $