(Compound annuity) What is the accumulated sum of each of the following streams of payments? a. $510 a year for 8 years compounded annually at 11 percent. b. $108 a year for 6 years compounded annually at 7 percent. c. $36 a year for 11 years compounded annually at 12percent. d. $26 a year for 4 years compounded annually at 5 percent. a. What is the accumulated sum of $510 a year for 8 years compounded annually at 11 percent? $ (Round to the nearest cent.) b. What is the accumulated sum of $108 a year for 6 years compounded annually at 7 percent? $ (Round to the nearest cent.) c. What is the accumulated sum of $36 a year for 11 years compounded annually at 12 percent? $ (Round to the nearest cent.) d. What is the accumulated sum of $26 a year for 4 years compounded annually at 5 percent? $ (Round to the nearest cent.)