Multiple choice

A $280 m$ train moving with an average speed of $108 km/h$ cross a platform in $12$ seconds.A boy crosses the same platform in $10$ seconds.What is the speed of boy in $m/s$?

  1. $5 m/s$
  2. $8 m/s$
  3. $10 m/s$

  4. Cannot be determined
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The train's speed is 108 km/h = 30 m/s. In 12 seconds it covers 360 m, so the platform is 360 - 280 = 80 m long, and the boy's speed is 80/10 = 8 m/s.

AI explanation

Convert the train's speed of 108 km/h to m/s by multiplying by 5/18, which gives 30 m/s. When crossing the platform in 12 seconds, the total distance covered is 30 m/s multiplied by 12 s, resulting in a platform length of 360 m. The boy crosses this same 360 m platform in 10 seconds, so his speed is 360 divided by 10, which equals 8 m/s.

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