Today is your 25th birthday (Happy Bday!). You plan on retiring 35 years from today. Every month you work, starting today (t=0), you wish to put an equal amount of money into a savings account with your last deposit on the day you retire. After you retire, you will need to withdraw $10,000 a month with your last withdrawal on your 80th birthday (first withdrawal is one month after you retire). Also when you turn 80, you plan on giving $100,000 to your grandchildren.

If the annual rate of interest is 9% (compounded monthly), how much do you need to deposit each month into your savings account?