[GMAT math practice question]
Is n<0?
1) n-1<0
2) |3-n| > |n+5|
Is n<0?
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- Max@Math Revolution
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Forget conventional ways of solving math questions. For DS problems, the VA (Variable Approach) method is the quickest and easiest way to find the answer without actually solving the problem. Remember that equal numbers of variables and independent equations ensure a solution.
Since we have 1 variable (n) and 0 equations, D is most likely to be the answer. So, we should consider each of the conditions on their own first.
Condition 1) : n - 1 < 0 => n < 1
Since the range of the question, n < 0 does not include that of the condition 1), n < 1, the condition 1) is not sufficient.
Condition 2) :
|3-n| > |n+5|
=> |3-n|^2 > |n+5|^2
=> (3-n)^2 > (n+5)^2
=> n^2 -6n + 9 > n^2 +10n + 25
=> -16 > 16n
=> n < -1
Since the range of the question includes that of the condition 2), the condition 2) is sufficient.
Therefore, B is the answer.
If the original condition includes "1 variable", or "2 variables and 1 equation", or "3 variables and 2 equations" etc., one more equation is required to answer the question. If each of conditions 1) and 2) provide an additional equation, there is a 59% chance that D is the answer, a 38% chance that A or B is the answer, and a 3% chance that the answer is C or E. Thus, answer D (conditions 1) and 2), when applied separately, are sufficient to answer the question) is most likely, but there may be cases where the answer is A,B,C or E.
Answer: B
Forget conventional ways of solving math questions. For DS problems, the VA (Variable Approach) method is the quickest and easiest way to find the answer without actually solving the problem. Remember that equal numbers of variables and independent equations ensure a solution.
Since we have 1 variable (n) and 0 equations, D is most likely to be the answer. So, we should consider each of the conditions on their own first.
Condition 1) : n - 1 < 0 => n < 1
Since the range of the question, n < 0 does not include that of the condition 1), n < 1, the condition 1) is not sufficient.
Condition 2) :
|3-n| > |n+5|
=> |3-n|^2 > |n+5|^2
=> (3-n)^2 > (n+5)^2
=> n^2 -6n + 9 > n^2 +10n + 25
=> -16 > 16n
=> n < -1
Since the range of the question includes that of the condition 2), the condition 2) is sufficient.
Therefore, B is the answer.
If the original condition includes "1 variable", or "2 variables and 1 equation", or "3 variables and 2 equations" etc., one more equation is required to answer the question. If each of conditions 1) and 2) provide an additional equation, there is a 59% chance that D is the answer, a 38% chance that A or B is the answer, and a 3% chance that the answer is C or E. Thus, answer D (conditions 1) and 2), when applied separately, are sufficient to answer the question) is most likely, but there may be cases where the answer is A,B,C or E.
Answer: B
Math Revolution
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Score an excellent Q49-51 just like 70% of our students.
[Free] Full on-demand course (7 days) - 100 hours of video lessons, 490 lesson topics, and 2,000 questions.
[Course] Starting $79 for on-demand and $60 for tutoring per hour and $390 only for Live Online.
Email to : [email protected]