Two trains ' \(A\) ' and ' \(B\) ' of length ' \(l\) ' and ' \(4 l\) ' are travelling into a tunnel of length ' \(L\) ' in parallel tracks from opposite directions with velocities \(108\,km / h\) and \(72\,km / h\), respectively. If train '\(A\)' takes \(35\,s\) less time than train ' \(B\) ' to cross the tunnel then, length ' \(L\) ' of tunnel is \(...........\,m\) \(\text { (Given } L=60 l \text { ) }\)

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Answer & Solution

Correct Answer

(C) \(1800\)

Step-by-step Solution

Detailed explanation

\(\frac{60 \ell+4 \ell}{20}-\frac{61 \ell}{30}=35\)

\(\Rightarrow \ell=\frac{1050}{35}\)

\(\Rightarrow L=60 \ell=\frac{1050}{35} \times 60=1800\,m\)

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