2. a) \(\frac{3}{4} : \frac{5}{8}\), б) \(5 : 1 \frac{1}{9}\)

a) \(\frac{3}{4} : \frac{5}{8} = \frac{3}{4} \cdot \frac{8}{5} = \frac{3 \cdot 8}{4 \cdot 5} = \frac{3 \cdot 2}{1 \cdot 5} = \frac{6}{5} = 1 \frac{1}{5}\) б) \(5 : 1 \frac{1}{9} = 5 : \frac{10}{9} = 5 \cdot \frac{9}{10} = \frac{5 \cdot 9}{10} = \frac{1 \cdot 9}{2} = \frac{9}{2} = 4 \frac{1}{2}\)