Hi All,
This DS question can be solved by TESTing VALUES. You'll have to be thorough with your thinking though (the absolute value signs *hint* that you'll need to consider 0 and negative values as part of your work).
We're asked if |X-Z| > |X-Y|. This is a YES/NO question.
Fact 1: |Z| >|Y|
Since there's no mention of X, you might instinctively think that this is insufficient, but here's the PROOF:
IF...
X = 1
Y = 0
Z = 1
|1-1| is NOT > |1-0| so the answer to the question is NO.
IF...
X = -1
Y = 0
Z = 1
|-1-1| IS > |-1-0| so the answer to the question is YES.
Fact 2: 0 > X
This Fact doesn't mention Y or Z, so you might also instinctively think that this is insufficient, but here's the PROOF:
IF...
X = -1
Y = 0
Z = 1
|-1-1| IS > |-1-0| so the answer to the question is YES.
IF...
X = -1
Y = 0
Z = -2
Then |-1-(-2)| is NOT > |-1-0| so the answer to the question is NO.
Fact 2 is INSUFFICIENT.
Combined, we know...
|Z| > |Y|
0 > X
Thankfully, we already have all of the proof that we need (in the above examples)...
IF...
X = -1
Y = 0
Z = 1
|-1-1| IS > |-1-0| so the answer to the question is YES.
IF...
X = -1
Y = 0
Z = -2
Then |-1-(-2)| is NOT > |-1-0| so the answer to the question is NO.
Combined, INSUFFICIENT.
Final Answer:
GMAT assassins aren't born, they're made,
Rich