Two trains whose lengths are 450 meters and 300 meters are moving towards each other at the speed of 324 km/h and 216 km/h respectively.  If the distance b/w trains is 300 m.  In how much time these trains will cross each other?

7 sec

Total distance = 450 + 300 + 300 = 1050 m

Total speed    = 324 + 216 = 540 km/h

                                        = 540 × \(\frac{5}{18}\) = 150 m/sec

Time taken to cross each other = \(\frac{1050}{150}\) = 7 sec