5:25 16

$${\frac{5}{16}} : 25 = {\frac{5}{16}} \cdot {\frac{1}{25}} = {\frac{5}{16 \cdot 25}} = {\frac{5}{16 \cdot 5 \cdot 5}} = {\frac{1}{16 \cdot 5}} = {\frac{1}{80}}$$

Ответ: $$\frac{1}{80}$$