Multiple choice

A person standing on a railway platform noticed that a train takes 18 seconds to cross the platform of length 72 m. and it takes 12 seconds to cross him. Find the speed of the train (in km/hr.)? एक प्लेटफार्म पर खड़ा हुआ एक व्यक्ति यह ध्यान देता है कि एक ट्रेन 72 मी. लम्बाई के प्लेटफार्म को 18 सेकेण्ड में एवं उसे 12 सेकेण्ड में पार करती है। ट्रेन की चाल ज्ञात कीजिए। (किमी./घंटा)

  1. 42.3

  2. 43.2

  3. 46.5

  4. 45.6
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let train length = L and speed = v. Crossing platform: (L+72)/v = 18. Crossing person: L/v = 12, so L = 12v. Substituting: (12v+72)/v = 18 → 12v+72 = 18v → 6v = 72 → v = 12 m/s. In km/hr: 12 × (18/5) = 43.2 km/hr.

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