These are the correct answers to the problem but I am completely lost on how to solve them.

please show the steps to solving this problem... even if your answer is a little different. these answers are directly from the textbook.

140. Wei Min opens a retirement account that pays 8%/year/month. For the next 30 years he deposits $300 per month into it, with all deposits occurring at the end of the month. On the day of the last deposit, Wei Min retires. As a benefit to retirees, the bank increases the interest rate to 12%/year/quarter from that time on. His first withdrawal will occur exactly 2 years after his last deposit. He then plans to make equal quarterly withdrawals from the account. a. What is the balance of the account immediately after the last monthly deposit? ANSWER $477,120.00 b. What is the balance of the account one quarter before the first quarterly withdrawal? ANSWER $549,899.47 c. What quarterly amounts can be withdrawn to last for 15 years? ANSWER O $19,867.87