Two trains P and Q of lengths 320 m and 540 m, respectively, are running in the same direction on parallel tracks at 108 km/h and 144 km/h, respectively. How much time will the trains take to cross each other completely?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 86 s.
Length of train P = 320 m
Length of train Q = 540 m
Speed of train P = 108 km/h
Speed of train Q = 144 km/h
Relative speed of trains moving in same direction = Speed of train P - Speed of train Q
Time =
According to the question,
Relative speed of trains = Speed of train P - Speed of train Q
⇒ 144 - 108 = 36 km/h
⇒ = 10 m/s
Total distance = 320 + 540 = 860 m
Time to cross each other = = = 86 sec