GMATPrepNow
Is (y - 3x)/(y - 2x) > 1?
(1) (y - 2x)/x < 0
(2) y - 2x > 0
Let's spend a little time at the beginning to
rephrase the target question.
Target question: Is (y - 3x)/(y - 2x) > 1? We can use a nice property of fractions to simplify this target question.
The property is (a + b)/c = a/c + b/c.
We can also write: (a - b)/c = a/c - b/c
Given:
(y - 3x)/(y - 2x) > 1Rewrite numerator as: (
y - 2x - x)/(
y - 2x) > 1
Apply fraction property to get: (
y - 2x)/(
y - 2x) - x/(
y - 2x) > 1
Simplify: 1 - x/(y - 2x) > 1
Subtract 1 from both sides: -x/(y - 2x) > 0
Add x/(y - 2x) to both side to get: 0 > x/(y - 2x)
Great, we've taken the inequality
(y - 3x)/(y - 2x) > 1 and rewritten it as
x/(y - 2x) < 0REPHRASED target question: Is x/(y - 2x) < 0? With this easier (REPHRASED) target question, it will be very easy to handle the statement...
Statement 1: (y - 2x)/x < 0 PERFECT!
If (y - 2x)/x is negative, then the reciprocal, x/(y - 2x) must also be negative.
In other words, we can be certain that
x/(y - 2x) < 0Since we can answer the
REPHRASED target question with certainty, statement 1 is SUFFICIENT
Statement 2: y - 2x > 0 This tells us that the DENOMINATOR in
x/(y - 2x) is positive, but we don't know anything about the numerator x.
So, we can't determine whether or not
x/(y - 2x) < 0 Since we cannot answer the
REPHRASED target question with certainty, statement 2 is NOT SUFFICIENT
Answer: A
RELATED VIDEO FROM OUR COURSE