Two trains 160 m and 200 m long, running in opposite directions on parallel tracks, cross each other in 12 seconds. If one train runs at 45 km/h, what is the speed of the other?

Explanation

1. 01

   Combined length = 360 m, so relative speed $= \frac{360}{12} = 30$ $m/s = 108$ km/h.

2. 02

   Opposite directions: speeds add, so the other train runs at $108 - 45 = 63$ km/h.