Multiple choice

A train crosses an electric pole in 18 seconds and crosses 250 m long tunnel in 36 seconds. What is the speed of the train?

  1. 40 kmph

  2. 50 kmph

  3. 60 kmph

  4. 80 kmph
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let L be the length of the train and v be its speed. From the first condition, L = v * 18. From the second, L + 250 = v * 36. Substituting the first into the second gives 18v + 250 = 36v, so 18v = 250, v = 250/18 m/s. Converting to kmph: (250/18) * (18/5) = 50 kmph.

AI explanation

Let the length of the train be L and its speed be S. The equations for crossing the pole and the tunnel are L equals 18 times S, and L plus 250 equals 36 times S. Substituting the first equation into the second gives 18 times S plus 250 equals 36 times S, which means 18 times S equals 250. The speed of the train is 250 divided by 18, which equals 125 by 9 m/s. Converting this to kmph gives 125 by 9 multiplied by 18 by 5, resulting in 50 kmph. The speed of the train is 50 kmph.

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