Question

lois invests 650 every 6 months at 4.6%/a compounded semi-annually for 25 years. How much interest will she earn after the 25th year

Answer 1

Future value annuity is given by:
FV=P[((1+r)^n-1)/r]
From the information:
P=650
r=0.046/2=0.023
n=25*2=50

Plugging our values in the formula we get:
FV=650[((1+0.023)^50-1)/0.023]
FV=59837.365