a) PMT = $123.25 + $123.25 = $246.50
b) The future value of the account after 11 years can be calculated using the formula for compound interest: FV = PV(1 + r/n)^(nt), where PV is the initial investment, r is the annual interest rate (6.3% = 0.063), n is the number of compounding periods per year (12 for monthly compounding), and t is the number of years. In this case, PV = $246.50, r = 0.063/12 = 0.00525, n = 12, and t = 11.
FV = $246.50(1 + 0.00525/12)^(12*11)
FV = $246.50(1 + 0.0004375)^132
FV = $246.50(1.0004375)^132
FV β $488.90
c) To find the future value of the account after the extra 14 years, we use the same formula but with t = 14.
FV = $488.90(1 + 0.00525/12)^(12*14)
FV = $488.90(1 + 0.0004375)^168
FV = $488.90(1.0004375)^168
FV β $988.24
d) The total interest earned over the course of the 25-year investment can be found by subtracting the total contributions from the total future value of the account:
Total interest = FV - (PMT*12*25)
Total interest = $988.24 - ($246.50*12*25)
Total interest = $988.24 - $73950
Total interest β $248.24