Discussion :: Problems on Trains
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What is the length of a running train crossing another 180 metre long train running in the opposite direction?
I.The relative speed of the two trains was 150 kmph.
II.The trains took 9 seconds to cross each other.
A.
I alone sufficient while II alone not sufficient to answer |
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B.
II alone sufficient while I alone not sufficient to answer |
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C.
Either I or II alone sufficient to answer |
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D.
Both I and II are not sufficient to answer |
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E.
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Answer : Option E
Explanation :
Let the two trains of length a metres and b metres be moving in opposite directions at u m/s and v m/s.
Time taken to cross each other = | \((\frac { a+b} { u+v} ) sec\)sec. | |
Now, b = 180, u + v = | \( (150\times\frac{5}{18})m/sec\)= | \( (\frac { 125 } { 3 } ) m/sec\)m/sec. | ||||||
9 = \((\frac { a+180 } { (125/3) } )\) | |
a = (375 - 180) = 195 m.
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