Ответ:

\[\frac{5}{6}+\frac{11}{12}=\frac{10}{12}+\frac{11}{12}=\frac{21}{12}=\frac{7}{4}.\]

\[\frac{8}{35}\cdot\frac{7}{4}=\frac{2}{5}.\]

Ответ: \(\frac{2}{5}\).