Please provide steps using a BA II Plus Financial calculator. If you're unable to provide steps with calculator, please be specific in steps. Thank you.

Your aunt has $270,000 invested at 5.5%, and she now wants to retire. She wants to withdraw $45,000 at the beginning of each year, beginning immediately. She also wants to have $50,000 left to give you when she ceases to withdraw funds from the account. For how many years can she make the $45,000 withdrawals and still have $50,000 left in the end?