з) 3 3/5 : 1 11/25;

$$3 \frac{3}{5} : 1 \frac{11}{25} = \frac{18}{5} : \frac{36}{25} = \frac{18}{5} \cdot \frac{25}{36} = \frac{18 \cdot 25}{5 \cdot 36} = \frac{18 \cdot 5 \cdot 5}{5 \cdot 18 \cdot 2} = \frac{5}{2} = 2 \frac{1}{2}$$