Part filled by tap A in 1 min = \( \Large \frac{1}{60} \) Let tap B fills the tank in x min Then, part filled by tap, B in 1 min = \( \Large \frac{1}{x} \) According to the question, = \( \Large \frac{1}{60} \) + \( \Large \frac{1}{x} \) = \( \Large \frac{1}{40} \) = \( \Large \frac{1}{x} \) = \( \Large \frac{1}{40} \) - \( \Large \frac{1}{60} \) => \( \Large \frac{1}{x} \) = \( \Large \frac{3-2}{120} \) => \( \Large \frac{1}{x} \) = \( \Large \frac{1}{120} \) Therefore, Tap B can fill the tank in 120 min.