Two trains 140 m and 160 m long run at the speed of 60 km hr and 40 km hr respectively in opposite d...........

Explanation:

Relative Speed = 60+40 = 100 kmph
= 100*(5/18) = 250/9 m/sec

Distance = 140+160 = 300 meters

Time = Distance/Speed

300 x 9/250 = 54/5 = 10.8s

So the time trains will take to cross each other will be 10.8 seconds

Hence, option 2 is the correct answer.