Given that <span>Martin's unpaid credit card balance was $1539.39 and his APR is 13.2%.
APR is the annual interest rate, to get the monthly interest rate, we divide the APR by 12.
Thus, monthly interest rate is </span>
The interest charge for the month is given by
, where P is the previous balance, i is the monthly interest rate.
Thus, interest charge is
The balance after the monthly interest charge = $1,539.39 + $16.93 = $1,556.32
Therefore, the balance after the new transaction is given by $1,556.32 + $178 = $1734.32
APR is the annual interest rate, to get the monthly interest rate, we divide the APR by 12.
Thus, monthly interest rate is </span>
The interest charge for the month is given by
Thus, interest charge is
The balance after the monthly interest charge = $1,539.39 + $16.93 = $1,556.32
Therefore, the balance after the new transaction is given by $1,556.32 + $178 = $1734.32