Two trains having lengths of 230 m and 240 m are 130 m apart. They start moving towards each other on parallel tracks, at speeds of 160 km/h and 200 km/h, respectively. In how much time will the trains cross each other?

6 sec

Total crossing length = 230 + 270 + 130 = 600 m

Relative speed ( when moves in opposite direction ) = 200 + 160 = 360 km /h

360 km/h = 360 × \(\frac{5 }{18 }\)   = 100 m/sec

Time = \(\frac{Distance  }{Speed }\) 

=  \(\frac{600 }{100 }\)  

= 6 sec

So , trains takes 6 sec to cross each other .