Multiple choice

A 330 meter long toy train crosses another 110 meter long toy train coming from opposite direction in 55 seconds. If the speed of a toy train is 12 km./hr. What is the speed of second toy train? एक 330 मीटर लम्बी खिलौना ट्रेन विपरीत दिशा से आ रही 110 मीटर लम्बी दूसरी खिलौना ट्रेन को 55 सेकेण्ड में पार कर लेती है यदि एक खिलौना ट्रेन की चाल 12 किमी./घं. हो तो दूसरी खिलौना ट्रेन की चाल क्या होगी?

  1. 12.8 km./hr.

  2. 14 km./hr.

  3. 16 km./hr.

  4. 16.8 km./hr.

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D Correct answer
Explanation

Total distance covered = sum of train lengths = 330 + 110 = 440 m = 0.44 km. Time = 55 seconds = 55/3600 hours. Relative speed = Distance/Time = 0.44/(55/3600) = 28.8 km/hr. Since trains move in opposite directions, relative speed = sum of individual speeds: 12 + v = 28.8, giving v = 16.8 km/hr.