Asad wrote:
An escalator moves downward from street level to a subway platform at a constant rate. When the escalator is turned off, Wesley takes 70 steps to descend from street level to the platform. When the escalator is turned on, Wesley needs only 36 steps to descend from street level to the platform. If Wesley begins at the platform and walks upward, against the escalator’s downward movement, how many steps will he need to take to reach street level? (Assume that Wesley walks at a constant rate in all scenarios.)
(A) Between 50 and 100 steps
(B) Between 100 and 200 steps
(C) Between 200 and 500 steps
(D) Between 500 and 1000 steps
(E) Over 1000 steps
DOWNWARD:
When the escalator is turned OFF, the number of steps taken by Wesley to travel downward = 70.
When the escalator is turned ON, the number of steps taken by Wesley to travel downward = 36, implying that the number of downward steps attributed to the escalator = 70-36 = 34.
Implication:
For every 36 steps taken by Wesley, the escalator moves downward 34 steps.
UPWARD:
For every 36 steps Wesley takes UPWARD, the escalator will move him DOWNWARD 34 steps, with the result that the net movement upward = 36-34 = 2 steps.
In other words, 36 upward steps taken by Wesley = a net upward movement of 2 steps.
Since Wesley must travel upward a total of 70 steps, we can set up the following proportion:
\(\frac{36-upward-steps-taken-by-Wesley}{net-gain-of-2-steps} = \frac{x-upward-steps-taken-by-Wesley}{70-steps}\)
\(\frac{36}{2} = \frac{x}{70}\)
\(18 = \frac{x}{70}\)
\(x = 18*70 = 1260\)
_________________
GMAT and GRE Tutor for over 20 years
Recent success stories for my students:admissions into Booth, Kellogg, HBS, Wharton, Tuck, Fuqua, Emory and others.
Available for live sessions in NYC and remotely all over the world
For more information, please email me at GMATGuruNY at gmail