• # question_answer A man sitting in a train travelling at the rate of 50 km/hr observes that it takes 9 seconds for a goods train travelling in the opposite direction to pass him. If the goods train is 187.5 m long, then its speed is A)  48 km/hr B)  28 km/hr C)  38 km/hr           D)  25 km/hr

[d] Let speed of good train = x km/h $=459=36\,km/hr.$ $t=\frac{187.5}{\left( 50+x \right)\times \frac{5}{18}}$ $450+9x=187.5\times \frac{18}{5}$ 450 + 9x = 675 x = 25 $\therefore$ Speed of good train = 25 km/h