Question
Train ‘A’ running with a speed of 54 km/hr. can
cross a standing goods train of 4 times its length in 20 seconds. Find the time taken by 240 meters long train ‘B’ which is coming from the opposite direction of train ‘A’, with a speed of 9 m/s, to cross-train ‘A’.Solution
Let the length of train ‘A’ be ‘x’ meters. Therefore, the length of the goods train = ‘4x’ meters Speed of train ‘A’ = 54 × (5/18) = 15 m/s According to the question, 4x + x = 15 × 20 => 5x = 300 => x = 60 Therefore, the time is taken by train ‘B’ to cross train ‘A’ = {(60 + 240)/ (15 + 9)} = 300/24=50/4=12.5second
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