you save 200 USD/month, you save those 200 USD per month in a bank account that offers a 5% interest rate compounded yearly, till the day you retire ( 25 years).

If you decide to do your deposits at the beginning of every month (so your first deposit will be done today) in a bank account that offers a 5% interest rate compounded monthly, and you continue doing so till the day you retire (25 years):

How much money will you have at the end?