Multiple choice

A train X speeding with 120 kmph crosses another train Y running in the same direction in 2 minutes If the lengths of the trains X and Y be 100 m and 200 m respectively what is the speed of train Y?

  1. 111 km/hr

  2. 123 km/hr

  3. 127 km/hr

  4. 129 km/hr
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Relative speed = (L1+L2) / Time = (100+200)m / 120s = 300/120 = 2.5 m/s. 2.5 m/s = 2.5 * 18/5 = 9 km/hr. Since they are in the same direction, V_x - V_y = 9. 120 - V_y = 9, so V_y = 111 km/hr.

AI explanation

Since the trains are moving in the same direction, the relative speed is the difference between their speeds. The total distance to cross is the sum of their lengths, which is 100 m + 200 m = 300 m. The time taken is 2 minutes, or 120 seconds, so the relative speed in meters per second is 300 divided by 120, equaling 2.5 m/s. Converting this to kilometers per hour by multiplying by 18/5 gives a relative speed of 9 km/hr. Since train X is speeding at 120 kmph, the speed of train Y is 120 - 9 = 111 km/hr.

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