Civil Services Prep

Prelims 2026 · CSAT / Quantitative Aptitude · Question 20

The speed of a train T is 100 km per hour and the speed of a person P is 4 km per hour. T crosses P in 15 seconds, if P travels along the direction of motion of T. If P travels along the opposite direction of T, then in how much time does T cross P, in seconds, approximately?<br/>

  1. 13.51
  2. 13.65
  3. 13.85
  4. 14.05

Answer

13.85

Same direction relative speed = 100 − 4 = 96 km/h = 26.67 m/s. Train length = 26.67 × 15 = 400 m. Opposite direction relative speed = 100 + 4 = 104 km/h = 28.89 m/s. Time = 400 / 28.89 ≈ 13.85 seconds.

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