Sheridan Service has a line of credit loan with the bank. The initial loan balance was $6000. Payments of $2000 and $3000 were made after four months and nine months, respectively. At the end of one year, Sheridan Service borrowed an additional $4000. Six months later, the line of credit loan was converted into a collateral mortgage loan. What was the amount of the mortgage loan if the line of credit interest was 9% compounded monthly?