Решение:
\[ 1\frac{5}{6} : 1\frac{1}{2} = \frac{11}{6} : \frac{3}{2} = \frac{11}{6} \times \frac{2}{3} = \frac{11}{3} \times \frac{1}{3} = \frac{11}{9} \]
\[ 2\frac{2}{3} + \frac{11}{9} = \frac{8}{3} + \frac{11}{9} = \frac{8 \times 3}{3 \times 3} + \frac{11}{9} = \frac{24}{9} + \frac{11}{9} = \frac{35}{9} = 3\frac{8}{9} \]
Ответ: \[ 3\frac{8}{9} \]