Two signal guns are fired from the same spot at an interval of 11 minutes 30 seconds. A person on a train approaching the spot hears the second shot 11 minutes after the first. If sound travels at 330 m/s, what is the speed of the train?
Correct answer C. 54 km/h
Explanation
In the time the train ran (660 s), it covered the distance sound travels in 30 s: 330 × 30 = 9900 m. Speed = 9900 / 660 = 15 m/s = 54 km/h.
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