[tex]\it \{x,\ y\}\ i.\ p.\ \{2,\ 5\} \Rightarrow x > y\\ \\ \\ x+y=350\ \ \ \ \ (1)\\ \\ \\ \{x,\ y\}\ i.\ p.\ \{2,\ 5\} \Rightarrow 2x=5y|_{+5x } \Rightarrow 2x+5x=5x+5y \Rightarrow 7x = 5(x+y)\Rightarrow \\ \\ \\ \stackrel{(1)}{\Longrightarrow}\ 7x=5\cdot350|_{:7} \Rightarrow x = 5\cdot50 \Rightarrow{x} = 250\ \ \ \ \ (2)\\ \\ \\ (1),\ (2) \Rightarrow 250+y=350 \Rightarrow y = 100[/tex]
