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?
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?
Explanation
When the trains move in opposite directions, their relative speed is the sum of their individual speeds:
60 km/h + 40 km/h = 100 km/h
To convert this to meters per second, divide by 3600 (since there are 3600 seconds in an hour):
100 km/h ÷ 3600 = 27.78 m/s (approximately)
The total distance covered by the trains as they cross each other is the sum of their lengths:
140 m + 160 m = 300 m
Time = Distance ÷ Relative Speed
Time = 300 m ÷ 27.78 m/s ≈ 10.8 s