Re: GMAT Diagnostic Test Question 13
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11 Mar 2012, 11:55
other people's confusions are starting to confuse me as well.. i concluded on (E) as well.. not sure if previous posts are still referring to incorrect wording, so hopefully someone could confirm if I'm going about this the right way?
13. Which of the following inequalities must be true for the value of x to be between -1 and 5 ?
i.e. (-1 < x < 5)
A. |3 – x| < -3
if x is (+):
3-x < -3
-x < -6
x > 6
if x is (-):
-3 - (-x) < -3
x < 0
** x<0 or x>6 ; doesn't satisfy
B. -1< |x| < 5
similarly,
-1 < x < 5 (if x is positive)
1 > x > -5 (if x is negative)
** even though first condition (when x is positive) satisfies the desired inequality, the second one (when x is negative), does not... for example, under the restriction (-1 < x < 5), x can be 0,1,2,3,4... but this answer choice allows for x to be 0, -1, -2, -3, -4 (or any fraction in between, since the question doesn't necessarily mention that x is an integer).. anyways, we can't assume x is positive or negative, which means the answer choice must satisfy what the question is asking under both conditions for it to be correct. Thus (B) is a wrong answer choice.
C. |x| - 2 > 2
Same reasoning,
x > 4
x < -4
wrong -- (allows for x to be outside required range)
D. |2 + x| > 3
x > 1 (x is positive)
x < -5 (x is negative)
wrong -- (allows for x to be outside required range)
E. |x – 2| < 3
x < 5
x > -1
** this answer choice gives (-1 < x < 5) --- the question was asking which inequality must be true in order for x to be somewhere between -1 and 5... (E) satisfies this condition.
not sure if I'm on the right track here; perhaps someone could verify?
thanks!