2023 · Q41
A train of length 400 m takes 15 seconds to cross a train of length 300 m travelling at 60 km per hour from the opposite direction along a parallel track. What is the speed of the longer train, in km per hour?
General SciencePhysics
- A108
- B102
- C98
- D96
Explanation
The trains move towards each other, so their relative speed is v + 60 km/h, and the total distance to be crossed is 400 + 300 = 700 m = 0.7 km. Time taken is 15 seconds = 15/3600 hour. So v + 60 = 0.7 / (15/3600) = 0.7 x 240 = 168, giving v = 108 km/h, option (a).