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Updated on: 13 Nov 2015, 05:39
Originally posted by excelingmat on 13 Nov 2015, 04:51.
Last edited by ENGRTOMBA2018 on 13 Nov 2015, 05:39, edited 1 time in total.
Last edited by ENGRTOMBA2018 on 13 Nov 2015, 05:39, edited 1 time in total.
Reformatted the question and the topic
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A
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
55%
(hard)
Question Stats:
60% (01:42) correct
40%
(01:55)
wrong
based on 70
sessions
History
Date
Time
Result
Not Attempted Yet
ENGRTOMBA2018
Joined: 20 Mar 2014
Last visit: 01 Dec 2021
Posts: 2,319
Given Kudos: 816
Concentration: Finance, Strategy
Schools: Kellogg '18 (M)
GMAT 1: 750 Q49 V44
GPA: 3.7
WE:Engineering (Aerospace and Defense)
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13 Nov 2015, 05:41
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excelingmat
The question asks, is |x|<3 ---> -3<x<3 ?
Per statement 1, x(x+3) < 0 ---> only possible scenario is for -3<x<0 ---> giving a "yes" to the question asked. Sufficient.
Per statement 2, x(x-3) > 0 ---> 2 scenarios, either x<0 (giving a "yes" for x =-1 but a "no" for x=-4), making this statement not sufficient. The other case is for x>3 (this would though give a "no" for th question asked). As this statement already gave you both "yes" and "no", this statement is not sufficient.
A is the correct answer.
17 Nov 2015, 10:26
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Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.
Let X be a real number. Is |x| < 3?
A. x(x + 3) < 0
B. x(x – 3) > 0
IF the range of the condition falls into that of the question, the condition is sufficient.
There is one variable and 2 equations are given by the conditions.
From condition 1, -3<x<0 is sufficient as the range of the question covers this range.
For condition 2, on the other hand, x<0, 3<x does not fall into the range of the question, so this is insufficient, and the answer becomes (A).
For cases where we need 1 more equation, such as original conditions with “1 variable”, or “2 variables and 1 equation”, or “3 variables and 2 equations”, we have 1 equation each in both 1) and 2). Therefore, there is 59 % chance that D is the answer, while A or B has 38% chance and C or E has 3% chance. Since D is most likely to be the answer using 1) and 2) separately according to DS definition. Obviously there may be cases where the answer is A, B, C or E.
Let X be a real number. Is |x| < 3?
A. x(x + 3) < 0
B. x(x – 3) > 0
IF the range of the condition falls into that of the question, the condition is sufficient.
There is one variable and 2 equations are given by the conditions.
From condition 1, -3<x<0 is sufficient as the range of the question covers this range.
For condition 2, on the other hand, x<0, 3<x does not fall into the range of the question, so this is insufficient, and the answer becomes (A).
For cases where we need 1 more equation, such as original conditions with “1 variable”, or “2 variables and 1 equation”, or “3 variables and 2 equations”, we have 1 equation each in both 1) and 2). Therefore, there is 59 % chance that D is the answer, while A or B has 38% chance and C or E has 3% chance. Since D is most likely to be the answer using 1) and 2) separately according to DS definition. Obviously there may be cases where the answer is A, B, C or E.
