A train takes 10 seconds to cross a pole and 20 seconds to cross a platform of length 200 m. What is the length of the train? एकट्रेन एक खम्भे को पार करने में 10 सेकेण्ड लेती है और एक 200 मी. लम्बे प्लेटफार्म को पार करने में 20 सेकेण्ड लेती है। ट्रेन की लम्बाई क्या है?
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50 m./मी.
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100 m./मी.
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150 m./मी.
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200 m./मी.
D
Correct answer
Explanation
Let the train's length be L meters and speed be s m/s. From crossing the pole: L = 10s, so s = L/10. From crossing the platform: L + 200 = 20s = 20(L/10) = 2L. Solving: L + 200 = 2L gives L = 200 meters. The train takes 10 seconds to cross a pole at its own speed, and 20 seconds to cover both its length and the 200m platform.