Two trains 140 m and 160 m long run at the speed of 60 km/hr and 40 km/hr, respectively in opposite directions on parallel tracks. The time (in seconds) which they take to cross each other is?

Question: Two trains 140 m and 160 m long run at the speed of 60 km/hr and 40 km/hr, respectively in opposite directions on parallel tracks. The time (in seconds) which they take to cross each other is?