\[m < n;\ \ \ \ так\ как:\]
\[\frac{3}{7}m = \frac{n \cdot 15}{100}\]
\[\frac{3}{7}m = \frac{5 \cdot 3}{5 \cdot 20}n\]
\[\frac{3}{7}m = \frac{3}{20}n\]
\[\frac{3}{7} > \frac{3}{20} \Longrightarrow m < n.\]