12) \(\frac{15}{28}\cdot1\frac{1}{6}\)

\(1\frac{1}{6}=\frac{7}{6}\).

\[\frac{15}{28}\cdot\frac{7}{6}=\frac{15}{24}=\frac{5}{8}.\]

Ответ: \(\frac{5}{8}\).