Multiple choice

The length of two trains is 240 m each. They cross a check post in 20 s and 30 s. If they travel in opposite directions towards each other, the time taken to cross each other is

  1. 12 s

  2. 16 s

  3. 20 s

  4. 24 s

  5. 28 s
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The speed of the first train is 240/20 = 12 m/s, and the second is 240/30 = 8 m/s. When moving in opposite directions, their relative speed is 12 + 8 = 20 m/s. The total distance to cover is 240 + 240 = 480 m, so time = 480 / 20 = 24 seconds.

AI explanation

Using the formula speed equals distance divided by time, the speeds of the two trains are 240 divided by 20 and 240 divided by 30, giving 12 m/s and 8 m/s. When moving in opposite directions, their relative speed is the sum, 20 m/s. The total distance to cross each other is the sum of their lengths, 480 m. The time equals distance divided by relative speed, 480 divided by 20, which is 24 s.

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