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

60 km/hr

Total Distance to cross each other = sum of length of trains = 100 +100 = 200m

Time = 8 sec

Relative Speed = \(\frac{Total\;distance}{Total\;time}\) = \(\frac{200}{8}\) = 25 m/sec = 25 × \(\frac{18}{5}\) km/hr = 90 km/hr

ATQ,

⇒ Speed of faster train = 2R

⇒ Speed of slower train = 1R

⇒Relative speed in opposite direction = 2R + 1R = 3R

3R = 90 km/hr

1R = 30 km/hr

2R = 60 km/hr = Speed of faster train.