Inequality

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Inequality

by jayanti » Fri Aug 05, 2011 4:08 am
Is �x�< 1?

(1) �x + 1� = 2�x - 1�
(2) �x - 3� ≠ 0
Source: — Data Sufficiency |

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by GMATGuruNY » Fri Aug 05, 2011 8:20 am
jayanti wrote:Is �x�< 1?

(1) �x + 1� = 2�x - 1�
(2) �x - 3� ≠ 0
Statement 1: �x + 1� = 2�x - 1|.
Case 1:
x + 1 = 2(x-1)
x + 1 = 2x - 2
x=3.

Case 2:
x + 1 = -2(x-1)
x + 1 = -2x + 2
3x = 1
x = 1/3.

Since |3| > 1 and |1/3| < 1, insufficient.

Statement 2: �x - 3� ≠ 0.
Thus, x ≠ 3.
Since x can be any value other than 3, insufficient.

Statements 1 and 2 combined:
Since statement 2 indicates that x ≠ 3, the only value that satisfies both statements is x = 1/3.
Sufficient.

The correct answer is C.
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