\(\left\{{}\begin{matrix}y-\frac{5}{6}x=100\\y+x=540\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}\frac{11}{6}x=440\\y+x=540\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=240\\y+240=540\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=240\\y=300\end{matrix}\right.\)