Multiple choice

A train speeding at $120$ km/hr crosses an electric pole in $9$ seconds and a platform in $24$ seconds. What is the length of the platform?

  1. $500$ m
  2. $800$ m
  3. $300$ m
  4. $1100$ m
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A Correct answer
Explanation

Speed = 120 km/hr = 120 * 5/18 = 100/3 m/s. Length of train = 100/3 * 9 = 300m. Time to cross platform = (300 + L) / (100/3) = 24. 300 + L = 800. L = 500m.

AI explanation

Convert the train's speed to meters per second by multiplying 120 by 5/18, which gives 100/3 m/s. The length of the train is the speed multiplied by the time it takes to cross a pole, so 100/3 times 9 equals 300 meters. When crossing the platform, the total distance covered is the train's length plus the platform's length, meaning 100/3 times 24 equals 300 plus the platform. Solving 800 = 300 + the platform gives a platform length of 500 meters.

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