[tex] \frac{x}{y} = \frac{3}{4} = > x = \frac{3y}{4} [/tex]
[tex] \frac{x + y}{4 } + 30 = 310[/tex]
[tex] \frac{x + y}{4} = 310 - 30 = 280[/tex]
[tex]x + y = 280 \times 4 = 1120[/tex]
[tex] \frac{3y}{4} + y = 1120[/tex]
[tex] \frac{3y + 4y}{4} = \frac{1120 \times 4}{4} [/tex]
[tex]7y = 1120 \times 4[/tex]
[tex]y = \frac{1120 \times 4}{7} = 160 \times 4 = 640[/tex]
[tex]x = \frac{3y}{4} = \frac{3 \times 640}{4} = 480[/tex]
