Part filled by A in 1 h = \( \Large 3 \times \frac{1}{18} \) Part filled by B in 1 h = \( \Large \frac{1}{6} \) Part filled by (A + B) = \( \Large \frac{1}{18} \)+\( \Large \frac{1}{6} \) = \( \Large \frac{1+3}{18} \) = \( \Large \frac{4}{18} \) = \( \Large \frac{2}{9} \) Here, both the pipes together will fill the tank in \( \Large \frac{9}{2} \) h or \( \Large 4\frac{1}{2} \)