A jogger running at 15 km/hr alongside a railway track 280 metres ahead of the…
2025
A jogger running at 15 km/hr alongside a railway track 280 metres ahead of the engine of a 180 metres long train running at 65 km/hr in the same direction. In how much time will the train pass the jogger?
Answer: A. 33.12 sec — Key steps to solve: Convert speeds from km/h to m/s. Train speed: 65 km/h = 65 × 5/18 = 325/18 m/s ≈ 18.06 m/s. Jogger speed: 15 km/h = 15 × 5/18 = 75/18 m/s…
- A.
33.12 sec
- B.
34.56 sec
- C.
35.15 sec
- D.
32.89 sec
Attempted by 6 students.
Show answer & explanation
Correct answer: A
Key steps to solve:
Convert speeds from km/h to m/s.
Train speed: 65 km/h = 65 × 5/18 = 325/18 m/s ≈ 18.06 m/s.
Jogger speed: 15 km/h = 15 × 5/18 = 75/18 m/s = 4.1667 m/s.
Find relative speed (train relative to jogger).
Relative speed = (325/18 − 75/18) = 250/18 = 125/9 m/s ≈ 13.8889 m/s.
Determine the distance the train must cover relative to the jogger for the train to pass completely.
Initial distance from engine to jogger = 280 m. The train length = 180 m. Total distance = 280 + 180 = 460 m.
Compute time = distance ÷ relative speed.
Time = 460 ÷ (125/9) = 460 × 9/125 = 4140/125 = 33.12 s (approximately).
Answer: 33.12 sec (approximately).