[tex] \frac{1}{3} < x < \frac{5}{7} \\ \frac{7}{21} < x < \frac{15}{21} \\ \frac{6}{7} = \frac{6 \times 3}{7 \times 3} = \frac{18}{21 } \\ \frac{1}{2} = \frac{1 \times 10.5}{2 \times 10.5} = \frac{10.5}{21} \\ \frac{3}{2} = 1 \frac{1}{2} [/tex]

Ответ: В) ½