A hint to get started
Track beginning-of-month deposits and monthly interest
A student deposits $10 on 1 January 2009 into an account paying compound interest on the last day of each month, then another $10 on the first day of each later month.
(a) How much interest has the original $10 earned after two years?
(b) What is the total balance after two years?
(c) After how many complete months does the total first exceed $2000?
[2008/I/10(ii)(modified)]
CJC · Discussion · Question 18
A deposit made at the start of the month earns interest at that month’s end.