14/5 : 7/2

$$\frac{14}{5} : \frac{7}{2} = \frac{14}{5} \cdot \frac{2}{7} = \frac{14 \cdot 2}{5 \cdot 7} = \frac{2 \cdot 2}{5 \cdot 1} = \frac{4}{5}$$