Juliens credit card charges an APR (annual percentage rate) of 18%. His credit card statement is monthly His bank savings account pays an interest rate of 3.6%, compounded monthly. If Julien withdraws $300 from his bank account to pay a credit card balance that would otherwise not be paid over the upcoming year, how much money will he save?

1. $58.69
2. $47.71
3. $43.20
4. $38.97

The answer is $47.71, but I would like to know the steps to get the answer