Выполним действия по порядку.
$$\frac{3}{17} + \frac{5}{34} + \frac{1}{2} = \frac{3 \cdot 2}{17 \cdot 2} + \frac{5}{34} + \frac{1 \cdot 17}{2 \cdot 17} = \frac{6}{34} + \frac{5}{34} + \frac{17}{34} = \frac{6+5+17}{34} = \frac{28}{34} = \frac{14}{17}$$
$$1 - \frac{11}{28} = \frac{28}{28} - \frac{11}{28} = \frac{28-11}{28} = \frac{17}{28}$$
$$\frac{14}{17} \cdot \frac{17}{28} = \frac{14 \cdot 17}{17 \cdot 28} = \frac{14}{28} = \frac{1}{2}$$
$$9 : \frac{6}{11} = 9 \cdot \frac{11}{6} = \frac{9 \cdot 11}{6} = \frac{3 \cdot 11}{2} = \frac{33}{2} = 16\frac{1}{2}$$
$$148\frac{1}{4} : 9 = \frac{148 \cdot 4 + 1}{4} : 9 = \frac{593}{4} : 9 = \frac{593}{4} \cdot \frac{1}{9} = \frac{593}{36} = 16\frac{17}{36}$$
$$16\frac{1}{2} - 16\frac{17}{36} = 16\frac{18}{36} - 16\frac{17}{36} = \frac{1}{36}$$
$$\frac{1}{2} : \frac{1}{36} = \frac{1}{2} \cdot 36 = 18$$
Ответ: 18