\[\frac{x + 2y}{2x} = 3\]
\[x + 2y = 6x\]
\[2y = 5x\]
\[y = 2,5x;\]
\[\frac{x}{y} - \frac{x - y}{3x} = \frac{x}{2,5x} - \frac{x - 2,5x}{2x} =\]
\[= \frac{10}{25} + \frac{1,5x}{2x} = 0,4 + 0,75 = 1,15.\]