\[= \frac{3}{10} \cdot \left( 1\frac{9}{12} + 2\frac{4}{12} \right)\ :\left( 7\frac{3}{6} - \frac{14}{6} \right) =\]
\[= \frac{3}{10} \cdot 3\frac{13}{12}\ :5\frac{5}{6} = \frac{3 \cdot 49 \cdot 6}{10 \cdot 12 \cdot 35} =\]
\[= \frac{21}{100} = 0,21.\]