42.
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Two trains 140 m and 160 m long run at the speed of 60 km/hr and 40 km/hr respectively in opposite directions on parallel tracks. The time (in seconds) which they take to cross each other, is:
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A.
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9
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B.
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9.6
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C.
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10
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D.
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10.8
|
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Answer: Option D
Explanation:
Relative speed = (60 + 40) km/hr =
|
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100 x
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5
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m/sec
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=
|
|
250
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m/sec.
|
18
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9
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Distance covered in crossing each other = (140 + 160) m = 300 m.
Required time =
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300 x
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9
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sec
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=
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54
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sec = 10.8 sec.
|
250
|
5
|
