Two trains A and B start from Howrah and Patna towards Patna and Howrah respectively at the same time. After passing each other, they take 4h 48 min and 3h 20 min to reach Patna and Howrah, respectively. If the train from Howrah is moving at 45 km/h, then the speed of the other train is

Given, a=45 km/h, y=?, \( \Large t_{1} \) = 4h 48 min and \( \Large t_{2} \) = 3 h 20 min

Using y = \( \Large a\sqrt{\frac{t_{1}}{t_{2}}}=45\sqrt{\frac{4 h \  and \  48 \  min}{3 h \  and \  20 \  min}} \)

= \( \Large 45\sqrt{\frac{\frac{24}{5}h}{\frac{10}{3}h}} \)

= \( \Large 45\sqrt{\frac{24 \times 3}{5 \times 10}} \)

= \( \Large 45 \times \sqrt{1.44}=45 \times 12 \) = 54 km/h