$4\mathrm{.}21$ Balloon Payments On $1$ September $2019,$ Susan Chao bought a motorcycle for $15,000.$ She paid $1,000$ down and financed

the balance with a $5-$year loan at a stated annual interest rate of $9\mathrm{.}6$ per cent, compounded monthly. She started the monthly

payments exactly $1$ month after the purchase $($i$.$e$.,1$ October $2019).$ Two years later, at the end of October $2021,$ Susan got a

new job and decided to pay off the loan. If the bank charges her a $1$ per cent prepayment penalty based on the loan Page $90$

balance, how much must she pay the bank on $1$ November $2021?$