Problems on Trains
2.  A train 125 m long passes a man, running at 5 km/hr in the same direction in which the train is going, in 10 seconds. The speed of the train is:  
Answer: Option B Explanation:
= 45 km/hr. Let the speed of the train be x km/hr. Then, relative speed = (x – 5) km/hr. x – 5 = 45 x = 50 km/hr. 
3.  The length of the bridge, which a train 130 metres long and travelling at 45 km/hr can cross in 30 seconds, is:  
Answer: Option C Explanation:
Time = 30 sec. Let the length of bridge be x metres.
2(130 + x) = 750 x = 245 m. 
4.  Two trains running in opposite directions cross a man standing on the platform in 27 seconds and 17 seconds respectively and they cross each other in 23 seconds. The ratio of their speeds is:  
Answer: Option B Explanation:
Let the speeds of the two trains be x m/sec and y m/sec respectively. Then, length of the first train = 27x metres, and length of the second train = 17y metres.
27x + 17y = 23x + 23y 4x = 6y

5.  A train passes a station platform in 36 seconds and a man standing on the platform in 20 seconds. If the speed of the train is 54 km/hr, what is the length of the platform?  
Answer: Option B Explanation:
Length of the train = (15 x 20)m = 300 m. Let the length of the platform be x metres.
x + 300 = 540 x = 240 m. 