Martin's unpaid credit card balance was $1539.39. his apr is 13.2%. what is his new balance after he makes one new transaction for $178 $1486.48 $1556.32 $1734.32 $1920.59

Given that 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 

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