A train crosses a bridge of length 2500 m in 120 seconds and a lamp post on the bridge in 30 seconds. What is the length of the train in metres ?  Choose the correct choice from the following choices:  A) 375 m  B) 750/3 m  C) 2500/3 m  D) 800 m  E) 300 m
Let Length of Train = L   Case-1: Distance = 2500+L (While crossing the bridge)   Time = 120 Seconds   i.e. Speed = Distance / Time = (2500+L)/120   Case-2: Distance = L (While passing the lamp post)   Time = 30 Seconds   i.e. Speed = Distance / Time = (L)/30   But Since speed has to be same in both cases so   (2500+L)/120 = (L)/30   i.e. 4L = 2500 + L   i.e. 3L = 2500   i.e. L = 2500/3   Answer: option 2500/3 m
<result>C</result>
A train crosses a bridge of length 2500 m in 120 seconds and a lamp post on the bridge in 30 seconds. What is the length of the train in metres ?