Hello, the correct answer for the problem is $3515.68 ; I have attempted it and keep getting an answer of $3421.64. I am familiar with most of the concepts involved however I think Im confusing the n term. Please post an explanation leading to the correct answer. Thank you for your help.

5.50 Beginning June 30, 1992, and every three months until December 31, 1996, Laura deposits $300 into her savings account. Starting September 30, 1997, she makes quarterly withdrawals of $500. What is the balance in her account after the withdrawal of June 30, 1999, if interest is at 74-8% until March 31, 1995, and 74-6% afterward? Ans. $3515.68