Question

Difficulty: HardInequalities, Absolute Values, and Number Ranges in Data Sufficiency

If xx and yy are real numbers such that x0x \neq 0, is xyx>1\frac{|x - y|}{x} > 1?

(1) x<0x < 0
(2) y<0y < 0

  1. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.Answer
  2. B
    Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
  3. C
    BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
  4. D
    EACH statement ALONE is sufficient.
  5. E
    Statements (1) and (2) TOGETHER are NOT sufficient.

Answer

Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
Statement (1) tells us x<0x < 0. Since xy0|x - y| \ge 0 for all real numbers, dividing a non-negative numerator by a negative denominator guarantees that xyx0\frac{|x - y|}{x} \le 0. Consequently, xyx\frac{|x - y|}{x} can never be greater than 11, giving a definitive 'No' answer to the question. Because Statement (1) provides a single definitive answer, it is sufficient. Statement (2) tells us y<0y < 0, but leaves the sign and value of xx unconstrained. Choosing x=1x = -1 with y=2y = -2 gives a value of 1-1 (answering 'No'), while choosing x=1x = 1 with y=2y = -2 gives a value of 33 (answering 'Yes'). Since Statement (2) allows both 'Yes' and 'No' outcomes, it is not sufficient. Thus, the option stating that Statement (1) alone is sufficient while Statement (2) alone is not sufficient is correct.

Step-by-Step Solution

1
Analyze the target question stem and algebraic constraints.
We are asked whether xyx>1\frac{|x - y|}{x} > 1. Notice that for any real numbers xx and yy, the absolute value in the numerator xy0|x - y| \ge 0. The sign of the denominator xx determines the sign of the entire quotient.
Understanding the algebraic behavior of non-negative numerators over signed denominators simplifies statement evaluation.
2
Evaluate Statement (1): x<0x < 0.
Since xy0|x - y| \ge 0 and x<0x < 0, the ratio xyx\frac{|x - y|}{x} is a non-negative number divided by a negative number. Thus, xyx0\frac{|x - y|}{x} \le 0. Since a number 0\le 0 can never be greater than 11, the answer to the question is a definitive 'No'. A definitive 'No' means the statement IS sufficient.
In Data Sufficiency, any statement that allows us to answer the question with a single, unambiguous 'Yes' or 'No' is sufficient.
3
Evaluate Statement (2): y<0y < 0.
Test values for xx while holding y<0y < 0 (e.g., y=2y = -2). If x=1x = -1, then 1(2)1=11=11\frac{|-1 - (-2)|}{-1} = \frac{1}{-1} = -1 \ngtr 1 (Answer: No). If x=1x = 1, then 1(2)1=31=3>1\frac{|1 - (-2)|}{1} = \frac{3}{1} = 3 > 1 (Answer: Yes). Because both 'Yes' and 'No' are possible, Statement (2) is not sufficient.
Getting conflicting answers from permissible test cases proves a statement is insufficient.

Key Concept

Definitive Yes/No logic and sign properties of absolute value quotients in Data Sufficiency
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