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A train travelling with uniform speed crosses two bridges of lengths 300 m and 240 m in 21
seconds and 18 seconds respectively. The speed of the train is :
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- 72 km/hr
- 68 km/hr
- 65 km/hr
- 60 km/hr
Correct Option: A
Let the length of the train be x.
| ∴ Speed of the train = | = | ||
| 21 | 18 |
| ⇒ | = | ||
| 7 | 6 |
⇒ 7x + 1680 = 6x + 1800
⇒ x = 120
| ∴ Speed of the train = | = | = 20 m/sec | ||
| 21 | 21 |
| = |  |  | kmph = 72 kmph | |
| 5 |
