15) 2 2/3 : 2 2/7

\(2\frac{2}{3}=\frac{8}{3}\), \(2\frac{2}{7}=\frac{16}{7}\).

\(\frac{8}{3}:\frac{16}{7}=\frac{8}{3}\cdot\frac{7}{16}=\frac{7}{6}=1\frac{1}{6}\).

Ответ: 1 1/6.