NandishSS wrote:210 college students were asked in a survey if they preferred Lindows- or Winux-based computers. 85 students claimed that they preferred Winux to Lindows. One-fourth as many of the students who preferred Lindows to Winux had no preference. How many of the students in the survey preferred Lindows- to Winux-based computers?
A. 25
B. 50
C. 75
D. 100
E. 125
Use a DOUBLE-MATRIX to organize the data.
Let L = prefer Lindows, NL = do not prefer Lindows, W = prefer Winux, NW = do not prefer Winux.
210 college students were asked in a survey if they preferred Lindows- or Winux-based computers.
The following matrix is yielded:
Since it is not possible to prefer BOTH L AND W -- a student who likes L more than W cannot also like W more than L -- the box in the upper left corner = 0.
85 students claimed that they preferred Winux to Lindows.
The following matrix is yielded:
One fourth as many of the students who preferred Lindows to W had no preference.
No preference = NL AND NW = the center box.
Since (NL AND NW) is equal to 1/4 of L, the following maxtrix is yielded:
The middle row implies the following:
x + (1/4)x = 125
(5/4)x = 125
x = (125*4)/5 = 100.
The correct answer is
D.
Last edited by
GMATGuruNY on Tue Mar 21, 2017 10:07 am, edited 1 time in total.
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