\[1)\ 3\frac{1}{6} - 1\frac{1^{\backslash 2}}{3} = 3\frac{1}{6} - 1\frac{1 \cdot 2}{6} = 2\frac{7}{6} - 1\frac{2}{6} =\]
\[= 1\frac{5}{6}\ (ч) - на\ путь\ из\ B\ в\ C.\]
\[2)\ 3\frac{1}{6} + 1\frac{5}{6} = 4\frac{6}{6} = 5\ (ч) - на\ путь\ \]
\[из\ A\ в\ C.\]
\[Ответ:\ 5\ ч.\ \]