Arithmetic Aptitude :: Problems on Trains
4. 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
speed of the faster train = 2x m/sec.
Relative speed of train = (x + 2x) m/sec = 3x m/sec.
Total distance = (100 + 100)m = 200m
3x = 200/8
=> 24x = 200 => x = 25/3
So speed of the faster train = 2 * 25/3 m/sec
= 50/3 m/sec
= 50/3 * 18/5 = 60 km/hr.