Mr. X takes 30 seconds to go up by using "moving up" escalator and takes 120 seconds to come down using "moving up" escalator. Find the time to move up when the escalator is standstill. Options: a)45  b)60  c) 75  d)48


Others Karthik on 14-Jan-2017 10:53

Mr. X takes 30 seconds to go up by using "moving up" escalator and takes 120 seconds to come down using "moving up" escalator. Find the time to move up when the escalator is standstill.

Options: a)45  b)60  c) 75  d)48

on 13-Apr-2014 18:02

Ans: 48 seconds.<br>Let the speed (steps covered by escalator) of moving up escalator be E steps per sec and the man be X steps per sec.<br>Let the total num of steps in covering the distance be N.<br>We need to find N/X (That is when E=0)<br>N/(X+E) = 30<br>N/(X-E) = 120<br>30X+30E = 120X - 120E,<br>150E = 90X,<br>5E=3X, E=3x/5.<br><br>Using eqn1, N/(X+3x/5) = 30,<br>N/(8X) = 6,<br>N/X = 48<br><br>
on 12-Mar-2016 11:32

Ans: 48 seconds. Let the speed (steps covered by escalator) of moving up escalator be E steps per sec and the man be X steps per sec. Let the total num of steps in covering the distance be N. We need to find N/X (That is when E=0) N/(X+E) = 30 N/(X-E) = 120 30X+30E = 120X - 120E, 150E = 90X, 5E=3X, E=3x/5. Using eqn1, N/(X+3x/5) = 30, N/(8X) = 6, N/X = 48
on 16-Mar-2017 11:57

First it is impossible to come down using "moving up" escalator when it is not in standstill position , according to question. From solution point of view its given that escalator is in standstill position.So Mr.X takes 120 seconds.