\(\frac{25}{15} = \frac{5 \cdot 5}{3 \cdot 5} = \frac{5}{3}\)
\(\frac{a^2}{1} \cdot \frac{1}{b} \cdot \frac{y}{y} = a^2 \cdot \frac{1}{b} \cdot 1 = \frac{a^2}{b}\)
\(\frac{5}{3} \cdot \frac{a^2}{b} = \frac{5a^2}{3b}\)
Ответ: \(\frac{5a^2}{3b}\)