ஒரு ரயிலானது ஒரு தந்தி கம்பம் மற்றும் 300 மீ நீளமுள்ள பாலத்தை முறையே 8,20 நொடிகளில் கடக்கிறது. எனில் ரயிலின் வேகம் என்ன? A train crosses a telegraph pole and a 300m long bridge in 8,20 seconds respectively. What is the speed of the train?

Let the length of the train be L and its speed be v. Crossing the telegraph pole means the train covers its own length in 8 seconds, so L = 8v. Crossing the 300 m bridge means the train covers L + 300 meters in 20 seconds, so L + 300 = 20v. We substitute the first equation into the second to get 8v + 300 = 20v, which gives 12v = 300 and v = 25 m/s. Converting this speed to km/h gives 25 * (18/5) = 90 km/h. The speed of the train is 90 km/h.

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