Motion In A Straight Line

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

(Given \(\mathrm{L}=60 l\) )