Answers

2016-04-27T18:00:09+05:30
The train crosses 90 km in 1 hour i.e. 3600 seconds 
so in 36 seconds it will cover    90/3600 x 36 = 9/10 km.

now 9/10 km is the length of  platform + length of the train

again length of the platform is double the train.
so (3 x length of train )= 9/10 km
so length of train is 9/10 x 1/3 = 3/10 km = 300 mtrs.
so the length of the platform is 600metres

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