In this question, the interest rate is 0.02% and you need to have $9.99 interest to cover the fee. To find the bank account needed, you need to divide the target interest value with the interest rate. The calculation would be:
interest = bank account * interest rate
$9.99 = bank account * 0.02%
bank account = $9.99/ 0.02% (don't forget the % mean 1/100)
bank account = $49,950