Question
Length of a train is two-thirds of the length of a
platform. If the train crosses the platform in 45 seconds, then find the time taken by train to cross a pole.Solution
Let the speed of train be 'v' m/s and the length of platform be '3L' metres.
Length of train = (2/3) X 3L = '2L' metres
So, (3L + 2L) = '45v'
Or, 5L = 45v
So, 'L' = 9v ---------- (I)
Required time = (2L/v)
= (18v/v) [from equation (I) ]
= 18 seconds
Hence, option c.
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