15. \(\left(\frac{1}{30}+\frac{7}{10}\right)\cdot6\)

\(\frac{1}{30}+\frac{7}{10}=\frac{1}{30}+\frac{21}{30}=\frac{22}{30}=\frac{11}{15}\).

\(\frac{11}{15}\cdot6=\frac{22}{5}=4\frac{2}{5}\).

Ответ: \(4\frac{2}{5}\).