$$\frac{3}{4}: (\frac{1}{2} + \frac{7}{16}) = \frac{3}{4} : (\frac{8}{16} + \frac{7}{16}) = \frac{3}{4} : \frac{15}{16} = \frac{3}{4} \cdot \frac{16}{15} = \frac{4}{5}$$
Ответ: $$rac{4}{5}$$