Question
Train ‘A’ can cross a pole in 8 seconds and a 80
metre long platform in 12 seconds. If the ratio of length of train ‘A’ and train ‘B’ is 2:5, respectively, then find the time taken by train ‘B’ to cross a pole with a speed of 25 m/s.Solution
Let the length and speed of the train ‘A’ be ‘l’ metre and ‘s’ m/s, respectively. According to question, l = 8s Also, 12s = 8s + 80 Or, 4s = 80 Or, s = 20 Therefore, length of train ‘A’ = 8s = 160 metres Length of train ‘B’ = 160 × (5/2) = 400 metres Required time taken = 400 ÷ 25 = 16 seconds
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