Let the speed of Moody be ' x ' steps/sec and that of the escalator be ' y ' steps/sec. In 30 seconds, Moody will finish riding the escalator when going in the same direction. Thus, total steps =30(x+y) If Moody's speed becomes twice, the time becomes 20 seconds. Thus, total steps =20(2x+y) Or 30x+30y=40x+20y Or x=y So, total steps =60y Time taken by only escalator =