[tex]\begin{gathered} t=\text{7 months} \\ r=7.2\text{ \%, but it must be monthly} \\ r=\frac{7.2\text{ \%}}{12}=0.6\text{ \%}=0.006 \\ I=231 \\ C=loan \\ I=Crt \\ Solving\text{ C} \\ C=\frac{I}{rt} \\ C=\frac{231}{\left(0.006\right)\left(7\right)} \\ C=5,500 \\ She\text{ borrowed \$5,500} \end{gathered}[/tex]
