61.35 7 10

$$1\frac{6}{7} \div 3\frac{5}{10} = \frac{13}{7} \div \frac{35}{10} = \frac{13}{7} \cdot \frac{10}{35} = \frac{13 \cdot 10}{7 \cdot 35} = \frac{130}{245} = \frac{26}{49}$$

Ответ: $$\frac{26}{49}$$.