Is that an OA?
My answer would be E. If, for example, we took y=1 and x = -1 then the question would read:
(-1/2) < 1 - z ?
(-3/2) < -z ?
(3/2) > z ?
Since we don´t have any information about z, then we cannot conclude whether z is less than 3/2...Can someone please explain what´s wrong with my reasoning?
Inequalities question
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Source: Beat The GMAT — Data Sufficiency |
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pemdas
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st(1) implies (x-y) can be either +ve or -ve depends on the value and sign of x. Not Sufficient
st(2) the same cause as in st(1) Not Sufficient
Combining st(1&2): y>0 and x<0 implies (x-y) is negative. On the left hand side we have negative value and on the right hand side we may have any value assigned to z.
1/(x-y) ... y-z
-1/(y-x) ... y-z
y-x>0 and y>x, but we don't know about z
Not Sufficient
The answer to this question cannot be c, are you sure this is OA and what's the source?
st(2) the same cause as in st(1) Not Sufficient
Combining st(1&2): y>0 and x<0 implies (x-y) is negative. On the left hand side we have negative value and on the right hand side we may have any value assigned to z.
1/(x-y) ... y-z
-1/(y-x) ... y-z
y-x>0 and y>x, but we don't know about z
Not Sufficient
The answer to this question cannot be c, are you sure this is OA and what's the source?
HG10 wrote:Is 1/(x - y) < y - z ?
1. y is positive
2. x is negative
Answer: C
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tomada
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If we were given a 3rd condition - say, that Z < 0 - we'd have an answer, since the right-hand side of the equation would necessarily be positive and the left-hand side would necessarily be negative. Alas, we do not have that 3rd condition.
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Troika
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Guys, I'm really sorry about this. The OA is indeed C. However, the question stem is 1/(x - y) < y - x and not 1/(x - y) < y - z. The 'z' was a typo.
Again, I'm really sorry about wasting your time over this typo. I'm generally careful about checking for typos; this one just slipped through. This is quite embarrassing.
Again, I'm really sorry about wasting your time over this typo. I'm generally careful about checking for typos; this one just slipped through. This is quite embarrassing.
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GMATGuruNY
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Statement 1: y is positiveHG10 wrote:Is 1/(x - y) < y - x ?
1. y is positive
2. x is negative
Answer: C
No restrictions on x.
Thus, it is possible x-y=1 or that x-y = -1.
If x-y = 1, then y-x = -1.
Plugging these values into 1/(x-y) < y-x, we get:
1/1 < -1
1 < -1.
NO.
If x-y = -1, then y-x = 1.
Plugging these values into 1/(x-y) < y-x, we get:
1/-1 < 1
-1 < 1.
YES.
Since in the first case the answer is NO, and in the second case the answer is YES, INSUFFICIENT.
Statement 2: x is negative
No restrictions on y.
Thus, it is possible that x-y=1 or that x-y = -1.
As we saw above, if x-y=1, then the answer to the question stem is NO, but if x-y=-1, then the answer to the question stem is YES.
INSUFFICIENT.
Statements 1 and 2:
Since x<0 and y>0, x-y<0 and y-x>0.
Plugging these conditions into 1/(x-y) < y-x, we get:
1/negative < positive.
negative < positive.
SUFFICIENT.
The correct answer is C.
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Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at [email protected].
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