6 +31.3 7.16 11 7 11.

$$7 \frac{6}{7} \cdot 1 \frac{6}{11} + 3 \frac{1}{7} \cdot \frac{3}{11} = \frac{7 \cdot 7 + 6}{7} \cdot \frac{1 \cdot 11 + 6}{11} + \frac{3 \cdot 7 + 1}{7} \cdot \frac{3}{11} = \frac{49 + 6}{7} \cdot \frac{11+6}{11} + \frac{21+1}{7} \cdot \frac{3}{11} = \frac{55}{7} \cdot \frac{17}{11} + \frac{22}{7} \cdot \frac{3}{11} = \frac{5 \cdot 17}{7} + \frac{2 \cdot 3}{7} = \frac{85}{7} + \frac{6}{7} = \frac{85+6}{7} = \frac{91}{7} = 13 $$

Ответ: 13