Two trains ‘A’ and ‘B’ of length ‘l’ and ‘4l’ 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 35s less time than train ‘B’ to cross the tunnel then, length ‘L’ of tunnel is
(Given L = 60 l)
(1) 1200 m
(2) 2700 m
(3) 1800 m
(4) 900 m
