CMA Foundation · Fundamentals of Business Mathematics and Statistics · Time and Distance
Two trains of lengths 120 m and 180 m run on parallel tracks in opposite directions at 40 km/h and 68 km/h respectively. How long will they take to completely cross each other?
They take 10 seconds to cross. Moving in opposite directions, their relative speed is 108 km/h, or 30 m/s, and they must cover the sum of their lengths, 300 m, so time equals 300 divided by 30.
- A8 seconds
- B10 seconds
- C12 secondsCorrect
- D15 seconds
Explanation
Relative speed in opposite directions = 40 + 68 = 108 km/h = 30 m/s. Total distance = 120 + 180 = 300 m. Time = 300/30 = 10 seconds. Check: 108 × 5/18 = 30, so the time is 10 s, not 12.
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