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A moving train crosses a man standing on a platform and a bridge 300 metres long in 10 seconds and 25 seconds respectively. What will be the time taken by the train to cross a platform 200 metres long ?
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16 2 seconds 3 - 18 seconds
- 20 seconds
- 22 seconds
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Correct Option: C
Let the length of the train be x metre
| Speed of train when it crosses man = | |
| 10 |
| Speed of train when it crosses platform = | |
| 25 |
According to the question,
| Speed of train = | = | ||
| 10 | 25 |
⇒ 25x = 10x + 3000
⇒ 15x = 3000
| ⇒ x = | = 200 metres | |
| 15 |
∴ Length of train = 200 metre
| Speed of train = | = | ||
| 10 | 10 |
| ∴ Time taken in crossing a 200 m long platform = | |
| 20 |
= 20 seconds
