Answer :
Recall the formula for determining the interest using simple interest
[tex]\begin{gathered} I=Prt \\ \text{where} \\ P\text{ is the principal amount} \\ r\text{ is the rate in decimal form} \\ t\text{ is time} \end{gathered}[/tex]Convert the rate into decimal form by dividing by 100%
[tex]7\%\div100\%=0.07[/tex]Substitute the following values
P = $1300, r = 0.07, t = 6/12 (12 months in a year, only 6 months has passed)
[tex]\begin{gathered} I=Prt \\ I=1300\cdot0.07\cdot\frac{6}{12} \\ I=91\cdot\frac{1}{2} \\ I=45.5 \end{gathered}[/tex]Therefore, Margo will pay back $45.50 in interest.