Correct Answer: 36 sec
Explanation:
Step 1: Convert speeds from km/h to m/s
Speed of train = 45 km/h = (45 × 1000) / 3600 = 12.5 m/s Speed of jogger = 9 km/h = (9 × 1000) / 3600 = 2.5 m/s
Step 2: Find the relative speed
Since both are moving in the same direction, subtract the jogger’s speed from the train’s speed.
Relative speed = 12.5 - 2.5 = 10 m/s
Step 3: Total distance to be covered to completely pass the jogger
The jogger is 240 meters ahead, and the train is 120 meters long. So, the train has to cover:
Distance = 240 + 120 = 360 meters
Step 4: Time to pass the jogger
Time = Distance / Relative Speed = 360 / 10 = 36 seconds
Answer: 36 seconds
The train will take 36 seconds to pass the jogger completely.
This is a classic example of a relative speed problem where both the train and the person are moving in the same direction. Understanding relative motion is crucial for solving such questions accurately in time-based aptitude exams.
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