A passenger coach locomotive 200 meters long passes a clear roadside post marker in 10 seconds flat. Find the time needed to cross an extensions platform 440 meters long. MCQ with Answer and Explanation
A passenger coach locomotive 200 meters long passes a clear roadside post marker in 10 seconds flat. Find the time needed to cross an extensions platform 440 meters long.
A. 40 seconds
B. 36 seconds
C. 32 seconds
D. 28 seconds
Answer: Option C
Solution (By JKExamLibrary)
Speed of coach locomotive = 200 / 10 = 20 m/s. Total distance to clear platform stretch = 200 + 440 = 640 meters. Time required = 640 / 20 = 32 seconds.
Explanation:
Let each side of square be 2400 km (LCM of 200, 400, 600, 800). Total distance = 4 * 2400 = 9600 km. Total time = 2400/200 + 2400/400 + 2400/600 + 2400/800 = 12 + 6 + 4 + 3 = 25 hours. Average speed = 9600 / 25 = 384 km/h.
Explanation:
New speed = 5/7 of usual speed => New time = 7/5 of usual time. Difference = 2/5 of usual time = 24 minutes. 1/5 of usual time = 12 minutes => Usual time = 60 minutes.
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