HarveyKlaus wrote:
If |x| = |y|, is x/y = -1?
(1) x < 0
(2) y > 0
Target question: Is x/y = -1? Given: |x| = |y| First of all, this tells us that x and y have the same
magnitude.
So, EITHER x and y are equal, OR one is negative and one is positive
Statement 1: x < 0 There's no information about y, so this statement probably isn't sufficient. let's TEST some values.
There are several values of x and y that satisfy statement 1. Here are two:
Case a: x = -2 and y = 2. Notice that |x| = |y|. In this case
x/y = (-2)/2 = -1Case b: x = -2 and y = -2. Notice that |x| = |y|. In this case
x/y = (-2)/(-2) = 1Since we cannot answer the
target question with certainty, statement 1 is NOT SUFFICIENT
Aside: For more on this idea of plugging in values when a statement doesn't feel sufficient, you can read my article: http://www.gmatprepnow.com/articles/dat ... lug-values Statement 2: y > 0 There's no information about x, so this statement probably isn't sufficient. let's TEST some values.
There are several values of x and y that satisfy statement 2. Here are two:
Case a: x = -2 and y = 2. Notice that |x| = |y|. In this case
x/y = (-2)/2 = -1Case b: x = 2 and y = 2. Notice that |x| = |y|. In this case
x/y = 2/2 = 1Since we cannot answer the
target question with certainty, statement 2 is NOT SUFFICIENT
Statements 1 and 2 combined Statement 1 tells us that x is negative
Statement 2 tells us that y is positive
The given information tells us that x and y must have the same magnitude.
So, we can conclude that
x/y = -1Since we can answer the
target question with certainty, the combined statements are SUFFICIENT
Answer = C
Cheers,
Brent
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