A train is moving with a uniform speed. Train crosses a bridge of length 340 meters in 35 seconds and a bridge of length 460 meters in 38 seconds. What is the speed of thetrain?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 144 km/hr.
| Understanding/Application |
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Let the length of the train be l. Length of first bridge = 340 m Time taen to cross first bridge = 35 sec Length of second bridge = 460 m Time etaken to cross second bridge = 38 sec When train crosses first bridge - Length of train + Length of bridge = l + 340 Speed of train = (l + 340)/35 When train crosses second bridge - Length of train + Length of bridge = l + 460 Speed of train = (l + 460)/38 |
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ATQ - Speed is uniform (l + 340)/35 = (l + 460)/38 38l + 12920 = 35l + 16100 3l = 16100 - 12920 = 3180 l = 1060 m Speed of train = (1060 + 340)/35 = 1400/35 = 40 m/s Speed of train = (40 × 18)/5 = 144 km/hr |