Question
Train ‘A’ can cross a pole in 4 seconds and a 150
metre long platform in 10 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 = 4s Also, 10s = 4s + 150 Or, 6s = 150 Or, s = 25 Therefore, length of train ‘A’ = 4s = 100 metres Length of train ‘B’ = 150 × (5/2) = 250 metres Required time taken = 250 ÷ 25 = 10 second
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