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:

Given

• Lengths = 140 m & 160 m
• Speeds = 60 km/h & 40 km/h (opposite)

ComputeRelative speed = (60 + 40) km/h = 100 km/h = 100 × (5/18) = 27.7778 m/sTotal distance = 140 + 160 = 300 mTime = 300 / 27.7778 = 10.8 s