\(\dfrac{0.\left(3\right)+0.\left(384615\right)+\dfrac{3}{13}x}{0.0\left(3\right)+13}=\dfrac{50}{85}\)
\(\Leftrightarrow\dfrac{\dfrac{28}{39}+\dfrac{3}{13}x}{\dfrac{391}{30}}=\dfrac{10}{17}\)
\(\Leftrightarrow x\cdot\dfrac{3}{13}+\dfrac{28}{39}=\dfrac{23}{3}\)
\(\Leftrightarrow x\cdot\dfrac{3}{13}=\dfrac{271}{39}\)
\(\Leftrightarrow x=\dfrac{271}{9}\)