we make a relation
[tex]\begin{gathered} \frac{4}{5}mi\longrightarrow\frac{1}{4}h \\ \\ 1mi\longrightarrow x \end{gathered}[/tex]where x is the number of hours that she takes to walk 1 mile
we solve using cross multiplication
[tex]\begin{gathered} x=\frac{1mi\times\frac{1}{4}h}{\frac{4}{5}mi} \\ \\ x=\frac{\frac{1}{4}h}{\frac{4}{5}} \\ \\ x=\frac{5}{16}h \end{gathered}[/tex]to walk 1 mile she takes 5/16 of an hour
