5 21 9 / 7 15 24 =

\( \frac{5}{7} : \frac{21}{15} : \frac{9}{24} = \frac{5}{7} \times \frac{15}{21} \times \frac{24}{9} = \frac{5 \times 15 \times 24}{7 \times 21 \times 9} = \frac{1800}{1323} = \frac{200}{147} \)

Ответ: \( \frac{200}{147} \)