Two trains, one 125 metres and the other 375 metres long are running in opposite directions on parallel tracks, at the speed of 81 km/hr and 63 km/hr respectively. How much time will they take to cross each other?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 12.5 seconds.
Length of trains = 125 + 375 = 500 m
Speeds = 81 km/hr and 63 km/hr
Relative speed (opposite directions) = 81 + 63 = 144 km/hr
Convert to m/s:
144 × 5/18 = 40 m/s
Time = Distance / Speed = 500 / 40 = 12.5 seconds