47.
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A train 800 metres long is running at a speed of 78 km/hr. If it crosses a tunnel in 1 minute, then the length of the tunnel (in meters) is:
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A.
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130
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B.
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360
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C.
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500
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D.
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540
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Answer: Option C
Explanation:
Speed =
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78 x
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5
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m/sec
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=
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65
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m/sec.
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18
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3
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Time = 1 minute = 60 seconds.
Let the length of the tunnel be x metres.
3(800 + x) = 3900
x = 500.
