A 220 m. long train is running with a speed of 62 km./hr. What is the time in which it will cross a man running at the speed of 4 km./hr. who starts from the engine in the direction opposite to that of the train?
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16 sec.
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12 sec.
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10 sec.
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15 sec.
B
Correct answer
Explanation
The train length is 220 m and its speed is 62 km/hr. The man runs opposite to the train at 4 km/hr. Relative speed = 62 + 4 = 66 km/hr = (66 × 5/18) m/s = 55/3 m/s. Time = Distance/Speed = 220 ÷ (55/3) = 220 × 3/55 = 12 seconds. Since the man starts from the engine and runs opposite to the train, he needs to cover the entire train length.