A train crosses a bridge of length 200 m in 10 seconds and a lamp post on the bridge in 5 seconds. What is the length of the train in metres?	Choices
A) 375 m  B) 750 m  C) 200 m  D) 800 m  E) 300 m
Let Length of Train = L   Case-1: Distance = 200+L (While crossing the bridge)   Time = 10 Seconds   i.e. Speed = Distance / Time = (200+L)/10   Case-2: Distance = L (While passing the lamp post)   Time = 5 Seconds   i.e. Speed = Distance / Time = (L)/5   But Since speed has to be same in both cases so   (200+L)/10 = (L)/5   i.e. 2L = L + 200   i.e. L = 200   Answer: option 200 m
<result>C</result>
A train crosses a bridge of length 200 m in 10 seconds and a lamp post on the bridge in 5 seconds. What is the length of the train in metres?