Two trains, 140 m and 120 m in length, are running in the same direction at the speed of 60 km/h and 78 km/h, respectively. In how much time will they completely cross each other?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e.52 seconds.
Given that, length of train 1 = 140 m
Length of train 2 = 120 m
Speed of train 1 = 60 km/h
Speed of train 2 = 78 km/h
When two trains run in same direction, the relatibve speed of the trains is equal to the difference in the individual speeds of the trains.
According to the given question,
Relative speed of trains = 78 - 60 = 18 km/h
Relative speed in m/sec = = 5 m/sec
Distance = Speed × Time
⇒ Time =
⇒ Time =
⇒ Time = 52
Hence they will completely cross each other in 52 seconds.