Two trains, each 100 m long, moving in opposite directions, cross each other in 8 seconds. If one is moving twice as fast the other, then the speed of the faster train is:

Given

• Each train length = 100 m.
• They move in opposite directions and cross in 8 s.
• One train is twice as fast as the other.

Let slower speed = u m/s, faster speed = 2u m/sRelative speed = u + 2u = 3uTotal distance to cross = 100 + 100 = 200 m200 = 3u × 8 ⇒ u = 25/3 m/sFaster speed = 2u = 50/3 m/s = (50/3) × 3.6 = 60 km/h