To save for Harman's post-secondary education starting in 18 years, his family deposits $1200 at the beginning of every year into an education fund earning inter-est at 4.15% compounded annually.

(a) What will be the balance in the fund after 18 years?

(b) How much of the balance will be interest?

(c) If the interest rate increases to 4.65% compounded annually, how much more interest is earned?