Using cross multiplication:
[tex]\begin{gathered} \frac{11}{\frac{4}{x}}=\frac{2}{5} \\ x=\frac{11}{4}\cdot\frac{5}{2} \\ x=\frac{55}{8}mi=6\frac{7}{8}mi \end{gathered}[/tex]Convert a mixed number to a fraction:
[tex]a\frac{c}{b}=\frac{a\cdot b+c}{b}[/tex]