The cost for each travel on this cab company can be expressed as a sum of the fixed fee and the price per mile multiplied by the distance in miles of the travel. Therefore:
[tex]c(m)=2+0.5\cdot m[/tex]If Sarah paid $7.5 for her cab, then c(m)=7.5 and we can use this value on the expression above to solve for "m". We have:
[tex]\begin{gathered} 7.5=2+0.5\cdot m \\ 0.5\cdot m=7.5-2 \\ 0.5\cdot m=5.5 \\ m=\frac{5.5}{0.5}=11 \end{gathered}[/tex]She traveled 11 miles.