[tex]\begin{array}{c c c}\sf Tempo &\sf Ratos&\sf Gatos\\\sf3&\sf3&\sf3\\\sf x&\sf100&\sf100\end{array}[/tex]
[tex]\sf300x=900[/tex]
[tex]\sf x=\dfrac{9\diagup\!\!\!\!0\diagup\!\!\!\!0}{3\diagup\!\!\!\!0\diagup\!\!\!\!0}[/tex]
[tex]\red{\boxed{\boxed{\sf x=3\,min}}} [/tex]
