Discussion :: Problems on Trains
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What is the length of a running train?
I.The train crosses a man in 9 seconds.II.The train crosses a 240 metre long platform in 24 seconds
A.
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B.
II alone sufficient while I alone not sufficient to answer |
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C.
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D.
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E.
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Answer : Option E
Explanation :
Time taken by train to cross a man = | \(\frac { Length of train } { Speed of train} \) Speed = | \(\frac { l } { 9 } \)....(i) | ||
Time taken by train to cross a platform = |
\(\frac {( Length of train + Length of platform) } { Speed of train} \) Speed = | \( \frac { l + 240 } { 24 } \)....(ii) | ||||||||||
From (i) and (ii), we get | \(\frac { l } { 9 } \)= | \(\frac { l+240 } { 24 }\) | ||
Thus, l can be obtained. So both I and II are necessary to get the answer.
The correct answer is (E).
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