Выполните действия: а) \(\left(3\frac{7}{30}-1\frac{5}{12}\right):18\frac{1}{6}\);

\(3\frac{7}{30}=\frac{97}{30}\), \(1\frac{5}{12}=\frac{17}{12}\), \(18\frac{1}{6}=\frac{109}{6}\).

\(\left(3\frac{7}{30}-1\frac{5}{12}\right):18\frac{1}{6}=\left(\frac{97}{30}-\frac{17}{12}\right):\frac{109}{6}=\left(\frac{194}{60}-\frac{85}{60}\right):\frac{109}{6}=\frac{109}{60}\cdot\frac{6}{109}=\frac{1}{10}.\)

Ответ: \(\frac{1}{10}\).