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A train with uniform speed crosses a 162m long platform in 36 seconds and another platform 120 m long in 30 seconds. Which of the following statements are correctA. As the length of the platform is changing, the time taken to cover the distance will also change. B. Speed of the train is 7 m/seconds.C. The length of the train is more than the length of platform 1.D. Train is 90 meters long.E. Length of both the platforms to be added to find the length of the train.Choose the correct options given below.1. Statement A, B, C are correct2. Statement A, B, D, E are correct3. Statement A, B, D are correct4. Statement A, C, E are correct |
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Answer» Correct Answer - Option 3 : Statement A, B, D are correct Formula Used: Speed = Distance/time Calculation: Let assume the length of the train = x m For platform 1 Speed = (Length of train + length of platform)/(Time) ⇒ Speed = (x + 162)/36 m/sec. .......................(1) For platform 2 Speed = (Length of train + length of platform)/(Time) ⇒ Speed = (x + 120)/30 m/sec. ................... (2) Speed is uniform So, From equation 1 and equation 2 ⇒ (x + 162)/36 = (x + 120)/30 ⇒ 5x + 810 = 6x + 720 ⇒ x = 90m Length of the train is 90m. Speed = Distance/time ⇒ Speed = (90+ 162)/36 ⇒ Speed = 7 m/seconds The length of the train is the same. The change in the time taken to cover the distance is because of the difference in length of the platforms. Conclusion: Statement A, B and D are correct The correct option is 3 i.e. Statement A, B and D are correct. |
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