Question
Train 'A' takes 36 seconds to pass a boy standing on a
platform, moving at a speed of 15 m/sec. The speeds of trains 'A' and 'B' are in the ratio of 5:6, and train 'B' is 372 meters longer than train 'A'. What is the time taken by both trains to cross each other when they are running in opposite directions?Solution
Length of train 'A' = 15 X 36 = 540 metres The length of train 'B' = 540 + 372 = 912 metres Speed of train 'B' = 15 X (6/5) = 18 m/s Relative speed of train 'B' w.r.t train 'A' when travelling towards each other: = 15 + 18 = 33 m/s Therefore, required time = (540 + 912) ÷ 33 = 44 seconds
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