Problem: (Compound annuity) What is the accumulated sum of each of the following streams of payments?
a. $500 a year for 10 years compounded annually at 5 percent
b. $100 a year for 5 years compounded annually at 10 percent
c. $35 a year for 7 years compounded annually at 7 percent
d. $25 a year for 3 years compounded annually at 2 percent.