\[\boxed{\mathbf{328\ (328).}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[\frac{3}{5} = \frac{6}{10} = 0,6;\ \ \ \ \ \frac{3}{4} = \frac{75}{100} = 0,75\]
\[0,6 \cdot 0,75 = 0,45 = \frac{45}{100} = \frac{9}{20}.\]