42. 3 2/5 : 1 2/3

$$3 \frac{2}{5} : 1 \frac{2}{3} = \frac{17}{5} : \frac{5}{3} = \frac{17}{5} \cdot \frac{3}{5} = \frac{17 \cdot 3}{5 \cdot 5} = \frac{51}{25} = 2 \frac{1}{25}$$

Ответ: $$2 \frac{1}{25}$$