Multiple choice

A fast train measuring 220 m in length moves at a speed of 80 km/h. How much total time does it require to fully cross a matching train measuring 180 m in length that is approaching from the opposite direction at 64 km/h?

  1. 8 seconds

  2. 10 seconds

  3. 12 seconds

  4. 14 seconds

  5. none
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Relative speed = 80 + 64 = 144 km/h = 144 * (5/18) = 40 m/s. Total distance = 220 + 180 = 400 m. Time = 400 / 40 = 10 seconds.

AI explanation

Because the trains are moving in opposite directions, add their speeds of 80 km/h and 64 km/h to get a relative speed of 144 km/h. Converting this relative speed to m/s gives 40 m/s. The total distance is the sum of their lengths, which is 400 m, and dividing this by the relative speed of 40 m/s gives a time of 10 seconds.

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