A 300-metre-long train crosses a platform in 39 seconds while it crosses a signal pole in 18 seconds. What is the length of the platform?  Choose the correct option:
A) 320 metres B) 650 metres C) 350 metres D) Data inadequate E) None of these
When a train crosses a platform, it crosses a distance equal to the sum of the length of the platform and that of the train. But when a train crosses a signal pole, it crosses the distance equal to its length only.   Here, time taken by the train to cross a signal pole = 18 seconds   Hence, speed of the train = 300⁄18 m/sec   The train takes 21 = (39 – 18) seconds extra in order to cross the platform.   Hence, length of platform = 21×300/18=350m   Answer 350 metres
<result>C</result>
A 300-metre-long train crosses a platform in 39 seconds while it crosses a signal pole in 18 seconds. What is the length of the platform?