Mrs. Kay who is 24 years old plans to retire at the age of 60. Mrs. Kay would like to be able to withdraw $120,000 per year from her retirement account for 40 years after retirement beginning a year after her retirement. She already has $15,000 in her retirement investment account that earns 7% per year. After retirement she plans to take less risk so she will move her investment into an account that earns 4.5% per year. How much does she need to invest each year in order to reach her goal?
can you explain how you got the answer.