$$1\frac{8}{17}: \left(\frac{12}{17}+2\frac{7}{11}\right) = \frac{25}{17} : \left(\frac{12}{17} + \frac{29}{11}\right) =$$
$$\frac{25}{17}: \left(\frac{12 \cdot 11 + 29 \cdot 17}{17 \cdot 11}\right) = \frac{25}{17} : \left(\frac{132 + 493}{187}\right) = \frac{25}{17} : \frac{625}{187} = $$
$$\frac{25}{17} \cdot \frac{187}{625} = \frac{25 \cdot 11 \cdot 17}{17 \cdot 25 \cdot 25} = \frac{11}{25} = 0,44$$
$$\mathbf{Ответ: 0,44}$$