if -2x > 3y ,is x negative ?
1)Y>0
2)2x+5y-20=0
OA D
if -2x > 3y ,is x negative ?
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Since -2x > 3y, x is negative only if y≥0.guerrero wrote:if -2x > 3y ,is x negative ?
1)Y>0
2)2x+5y-20=0
Question stem, rephrased:
Is y≥0?
Statement 1: y>0
SUFFICIENT.
Statement 2: 2x+5y-20=0
2x+5y-20 = 0.
5y-20 = -2x.
Substituting 5y-20 for -2x in -2x>3y, we get:
5y-20>3y
2y>20
y>10.
SUFFICIENT.
The correct answer is D.
Last edited by GMATGuruNY on Tue Jan 27, 2015 9:04 am, edited 1 time in total.
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Hi guerrero,
This DS question has a couple of Number Property "restrictions" built into it; recognizing those restrictions will make solving the problem easier.
We're told that -2X > 3Y, so we're faced with some immediate restrictions:
1) X and Y CANNOT BOTH be 0
2) X and Y CANNOT BOTH be positive
We're asked if X is NEGATIVE. This is YES/NO question.
Fact 1: Y > 0
This combined nicely with the restrictions we noted earlier. Since Y is positive, X CANNOT be positive. By TESTing Values (plug in any positive values you like for Y), you'll see that X CANNOT be 0 either. So if X cannot be positive nor 0, all that's left is for X to be negative. The answer to the question is ALWAYS YES.
Fact 1 is SUFFICIENT.
Fact 2: 2X + 5Y - 20 = 0
Notice that we have "2X" and the prompt has "-2X"; that is NOT a coincidence. It's there to provide you an opportunity to use a little algebra:
5Y - 20 = -2X
Now we can substitute in....
5Y - 20 > 3Y
2Y > 20
Y > 10
Since Y is positive, we can use the same Number Property deduction that we used in Fact 1: X MUST be negative and the answer to the question is ALWAYS YES.
Fact 2 is SUFFICIENT
Final Answer: D
GMAT assassins aren't born, they're made,
Rich
This DS question has a couple of Number Property "restrictions" built into it; recognizing those restrictions will make solving the problem easier.
We're told that -2X > 3Y, so we're faced with some immediate restrictions:
1) X and Y CANNOT BOTH be 0
2) X and Y CANNOT BOTH be positive
We're asked if X is NEGATIVE. This is YES/NO question.
Fact 1: Y > 0
This combined nicely with the restrictions we noted earlier. Since Y is positive, X CANNOT be positive. By TESTing Values (plug in any positive values you like for Y), you'll see that X CANNOT be 0 either. So if X cannot be positive nor 0, all that's left is for X to be negative. The answer to the question is ALWAYS YES.
Fact 1 is SUFFICIENT.
Fact 2: 2X + 5Y - 20 = 0
Notice that we have "2X" and the prompt has "-2X"; that is NOT a coincidence. It's there to provide you an opportunity to use a little algebra:
5Y - 20 = -2X
Now we can substitute in....
5Y - 20 > 3Y
2Y > 20
Y > 10
Since Y is positive, we can use the same Number Property deduction that we used in Fact 1: X MUST be negative and the answer to the question is ALWAYS YES.
Fact 2 is SUFFICIENT
Final Answer: D
GMAT assassins aren't born, they're made,
Rich