You plan on retiring after you turn $40.$ When you retire, you want to receive annual payment of $$50,000$ on your birthday beginning with your $41$st birthday up until your $80$th birthday. How much would you have to invest on your $20$th birthday at $6\%$ interest per year in order to fund that retirement cash flow

stream? You may assume that your account continues to earn interest after you start receiving the birthday payments.