Multiple choice

A boy in a train notices that he can count 31 telephone posts in 60 seconds. The distance between two posts is 60 metres. What is the speed of the train?

  1. 90 km/hr

  2. 108 km/hr

  3. 60 km/hr

  4. 120 km/hr

  5. N/A
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

31 posts mean 30 intervals. Total distance = 30 * 60 = 1800 meters. Time = 60 seconds. Speed = 1800/60 = 30 m/s. 30 m/s * 3.6 = 108 km/hr.

AI explanation

Since there are 31 telephone posts, there are 30 intervals between them. The total distance covered in 60 seconds is 30 multiplied by 60 metres, which equals 1800 metres or 1.8 kilometres. Since the train covers 1.8 km in 60 seconds, or one minute, its speed is 108 km/hr.

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