Решение:

и) $$ \frac{5}{8} : \frac{15}{28} = \frac{5}{8} \cdot \frac{28}{15} = \frac{5 \cdot 28}{8 \cdot 15} = \frac{5 \cdot 4 \cdot 7}{4 \cdot 2 \cdot 5 \cdot 3} = \frac{7}{2 \cdot 3} = \frac{7}{6} = 1\frac{1}{6} $$ Ответ: $$1\frac{1}{6}$$

к) $$ \frac{0.32}{4.8} = \frac{32}{480} = \frac{16 \cdot 2}{16 \cdot 30} = \frac{2}{30} = \frac{1}{15} $$ Ответ: $$\frac{1}{15}$$

л) $$0.8 - \frac{1}{6} = \frac{8}{10} - \frac{1}{6} = \frac{4}{5} - \frac{1}{6} = \frac{4 \cdot 6 - 1 \cdot 5}{5 \cdot 6} = \frac{24 - 5}{30} = \frac{19}{30}$$ Ответ: $$\frac{19}{30}$$

м) $$1.4 : \frac{2}{7} = \frac{14}{10} : \frac{2}{7} = \frac{14}{10} \cdot \frac{7}{2} = \frac{7 \cdot 2 \cdot 7}{5 \cdot 2 \cdot 2} = \frac{49}{10} = 4.9$$ Ответ: $$4.9$$