Multiple choice

A train of length $150$ m takes $10$ sec to pass over another train $100$ m long coming from opposite direction. If the speed of the first train be $30$ km/hr, then what is the speed of the second train ?

  1. $54$ km/hr
  2. $60$ km/hr
  3. $72$ km/hr
  4. $36$ km/hr
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Relative speed = (150+100)m / 10s = 25 m/s = 90 km/h. Relative speed = v1 + v2 = 30 + v2 = 90. v2 = 60 km/h.

AI explanation

When two trains cross each other from opposite directions, the total distance covered is the sum of their lengths: 150 m + 100 m = 250 m. The relative speed is the total distance divided by the time taken, which is 250 m / 10 s = 25 m/s. Converting this relative speed to kilometers per hour gives 25 * 18/5 = 90 km/hr. Since the first train's speed is 30 km/hr, the second train's speed is found by subtracting this from the relative speed: 90 km/hr - 30 km/hr = 60 km/hr. The speed of the second train is 60 km/hr.

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