13. \(\frac{10}{13}\) qismi 120 ga teng bo'lgan sonni toping.

Sonning \( \frac{m}{n} \) qismi \( a \) ga teng bo'lsa, u holda sonni quyidagicha topish mumkin: \( x = a \div \frac{m}{n} = a \times \frac{n}{m} \).

Masalada berilgan:

• \( \frac{m}{n} = \frac{10}{13} \)
• \( a = 120 \)

Sonni topamiz:

\( x = 120 \div \frac{10}{13} = 120 \times \frac{13}{10} = \frac{120 \times 13}{10} = 12 \times 13 = 156 \)

Ответ: 156