15. \(\left(1\frac{11}{16}-3\frac{2}{3}\right)\cdot4\)

\(1\frac{11}{16}=\frac{27}{16}\), \(3\frac{2}{3}=\frac{11}{3}\).

\(\left(\frac{27}{16}-\frac{11}{3}\right)\cdot4=\left(\frac{81-176}{48}\right)\cdot4=-\frac{95}{12}\).

Ответ: \(-\frac{95}{12}=-7\frac{11}{12}\).