Multiple choice

Two trains are travelling on parallel tracks in opposite directions. Train A is 130 metres long and travels at a speed of 90 km/h. Train B is 185 metres long and travels at a speed of 72 km/h. How long does it take for the two trains to completely pass each other?

  1. 4 seconds

  2. 6 seconds

  3. 7 seconds

  4. 9 seconds

  5. 11 seconds
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Total distance to cover = 130 + 185 = 315 meters. Relative speed = 90 + 72 = 162 km/h. Convert to m/s: 162 * (5/18) = 45 m/s. Time = Distance / Speed = 315 / 45 = 7 seconds.

AI explanation

Using the formula for relative speed, the combined speed of the two trains traveling in opposite directions is 90 km/h plus 72 km/h, totaling 162 km/h. Converting this to meters per second gives 162 multiplied by 5 by 18, which equals 45 m/s. The total distance to be covered for them to completely pass each other is the sum of their lengths, giving 130 m plus 185 m, which equals 315 m. The required time is distance divided by relative speed, giving 315 divided by 45, which is 7 seconds. The trains take 7 seconds to pass each other.

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