Quang deposits $20,000 in a savings account with a discount rate of 4.8% convertible quarterly. He leaves his money in this account to accumulate for twelve years, then moves it to a fund which is accumulating at 5.4% per annum convertible continuously. If, starting at time 12 when he invests in the new fund, money is withdrawn levelly and continuously at a rate of $8,000 per annum, how long will Quang's money last?

Please show me how to do this (including all the steps) The answer is : 17.10632 yrs, including the 12 years prior to any withdrawls

Thanks!