A boy invests a sum of $4000 on his 10th birthday in the year 1996, with an annual interest rate of 7%, compounded every six months. During some stage of the investment, the interest rate changes to an annual rate of 6%, still compounded every six months. On the boy's 18th birthday, the boy checks his account to see a sum of $6770. At what point in time did the interest rate change from 7% to 6%?
(In reply to
analytic solution by Charlie)
Yes! I agree that the interest change occurred when the boy was midway between his 15th and 16th birthday.
Edited on December 30, 2022, 6:28 am
re: analytic solution
