A 240 m long train overtakes a man walking at 6 km/h, in the same direction, in 9 seconds. How much time (in seconds) will it take to pass a 372 m long tunnel with the same speed?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 21.6
Speed = Distance/Time
Let the speed of train = x m/sec
Speed of the man = 6 km/h = 6 × 5/18 = 5/3 m/sec
According to the question
240 = (x – 5/3 ) × 9
⇒ 80 = (3x – 5)
⇒ 85 = 3x
⇒ x = 85/3 m/sec
Distance = Total distance covered by train and Tunnel = (240 + 372) m = 612 m
Speed = Distance/Time
⇒ [612/ (85/3)] = 21.6 sec