A jogger running at 9 kmph alongside a railway track in 240 metres ahead of the engine of a 120 metres long train running at 45 kmph in the same direction. In how much time will the train pass the jogger?

Given Data

• Jogger is 240 m ahead of the engine
• Train length = 120 m
• Speeds: train = 45 km/hr, jogger = 9 km/hr, same direction
• Required: time for the train to pass the jogger completely

Step 1: Relative speed (same direction ⇒ difference)
v_rel = 45 − 9 = 36 km/hr = 36 × (5/18) = 10 m/s

Step 2: Relative distance to cover
To completely pass the jogger, the train's front must cover 240 m gap + train length 120 mDistance = 240 + 120 = 360 mt = 360 ÷ 10 = 36 s

Checks & Common Pitfalls

• Add existing gap to train length for complete passing.
• Keep units consistent when converting speeds.

Final Answer
The train passes the jogger in 36 s.