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mehravikas
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Is x negative?
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Source: Beat The GMAT — Data Sufficiency |
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mehravikas
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I thought the same, but the answer is 'C'. I am not able to understand how the answer can be 'C'.pepeprepa wrote:I say E
I belive there is a typo. Maybe the first equation is as follows:mehravikas wrote:Is x negative?
1. n^3 (1 - x^2) < 0
2. x^2 - 1 < 0
1. x^3 (1 - x^2) < 0
But even then the answer is not C. It's A.
From Equation 1:
x^3 (1 - x^2)
= x^3 - x^5 < 0
= x^3 < x^5
Thus x can't be negative or a fraction of the form p/q where p<q. SUFFICIENT.
From Equation 2:
x^2 - 1 < 0
= x^2 < 1
Thus x can either be negative or a fraction of the form p/q where p<q.
INSUFFICIENT.
I hope this helps.
Cheers.
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mehravikas
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I think you are right.
axat wrote:I belive there is a typo. Maybe the first equation is as follows:mehravikas wrote:Is x negative?
1. n^3 (1 - x^2) < 0
2. x^2 - 1 < 0
1. x^3 (1 - x^2) < 0
But even then the answer is not C. It's A.
From Equation 1:
x^3 (1 - x^2)
= x^3 - x^5 < 0
= x^3 < x^5
Thus x can't be negative or a fraction of the form p/q where p<q. SUFFICIENT.
From Equation 2:
x^2 - 1 < 0
= x^2 < 1
Thus x can either be negative or a fraction of the form p/q where p<q.
INSUFFICIENT.
I hope this helps.
Cheers.
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jackcrystal
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mehravikas wrote:Is x negative?
1. n^3 (1 - x^2) < 0
2. x^2 - 1 < 0
I think its C.
x^2 - 1 < 0
x^2 < 1
then, in [1] (1-x^2) is positive. Thus x^3 is responsible for negative value.
Ans. C
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mehravikas
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How can you say that in statement 1, 1 - x^2 is positive?
jackcrystal wrote:mehravikas wrote:Is x negative?
1. n^3 (1 - x^2) < 0
2. x^2 - 1 < 0
I think its C.
x^2 - 1 < 0
x^2 < 1
then, in [1] (1-x^2) is positive. Thus x^3 is responsible for negative value.
Ans. C
