48. 3 2/5:7/51−5/21

\(3\frac{2}{5}:\frac{7}{51}=\frac{17}{5}\cdot\frac{51}{7}=\frac{867}{35}\).

\(\frac{867}{35}-\frac{5}{21}=\frac{2601}{105}-\frac{25}{105}=\frac{2576}{105}=24\frac{56}{105}=24\frac{8}{15}\).

Ответ: 24\(\frac{8}{15}\)