|
|
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
12 Jul 2014, 16:09
Kudos
Bookmarks
E
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
65%
(hard)
Question Stats:
59% (02:09) correct
41%
(01:54)
wrong
based on 516
sessions
History
Date
Time
Result
Not Attempted Yet
What is the value of \(xy?\)
(1) \(x^2y^2+2xy\pi-3\pi^2 = 0\)
(2) \(xy>-9.5\)
Experience GMAT Club Test Questions
Yes, you've landed on a GMAT Club Tests question
Craving more? Unlock our full suite of GMAT Club Tests here
Want to experience more? Get a taste of our tests with our free trial today
Rise to the challenge with GMAT Club Tests. Happy practicing!
Pure algebraic questions like this one are no longer part of the GMAT Data Sufficiency syllabus.
For relevant Data Sufficiency questions, please check the Data Sufficiency forum:
Data Sufficiency Forum
Data Sufficiency Forum
12 Jul 2014, 16:09
Kudos
Bookmarks
SOLUTION
What is the value of \(xy\)?
(1) \(x^2y^2+2xy\pi-3\pi^2 = 0\).
This can be expressed as: \((xy)^2 + 2xy\pi - 3\pi^2 = 0\).
To find the value of \(xy\), we can either directly solve the quadratic for \(xy\) (to simplify, we can denote \(xy\) as \(a\) to get \(a^2 + 2a\pi - 3\pi^2 = 0\) and solve for \(a\)), or factor \((xy)^2 + 2xy\pi - 3\pi^2 = 0\):
\((xy)^2 + 3xy\pi - xy\pi - 3\pi^2 = 0\)
\((xy)(xy + 3\pi) - \pi(xy + 3\pi) = 0\)
\((xy+3\pi)(xy-\pi)=0\)
This gives us two possible solutions: \(xy=-3\pi\) or \(xy=\pi\). This statement is not sufficient to determine a unique solution.
(2) \(xy>-9.5\).
Clearly insufficient.
(1)+(2) From (1), we have two possible values: \(xy = -3\pi \approx -9.45\) and \(xy = \pi \approx 3.14\). Since both values are greater than -9.5, they both satisfy the condition in statement (2). Therefore, even with both statements, we cannot uniquely determine the value of \(xy\). Not sufficient.
Answer: E
Try NEW Algebra PS question.
What is the value of \(xy\)?
(1) \(x^2y^2+2xy\pi-3\pi^2 = 0\).
This can be expressed as: \((xy)^2 + 2xy\pi - 3\pi^2 = 0\).
To find the value of \(xy\), we can either directly solve the quadratic for \(xy\) (to simplify, we can denote \(xy\) as \(a\) to get \(a^2 + 2a\pi - 3\pi^2 = 0\) and solve for \(a\)), or factor \((xy)^2 + 2xy\pi - 3\pi^2 = 0\):
\((xy)^2 + 3xy\pi - xy\pi - 3\pi^2 = 0\)
\((xy)(xy + 3\pi) - \pi(xy + 3\pi) = 0\)
\((xy+3\pi)(xy-\pi)=0\)
This gives us two possible solutions: \(xy=-3\pi\) or \(xy=\pi\). This statement is not sufficient to determine a unique solution.
(2) \(xy>-9.5\).
Clearly insufficient.
(1)+(2) From (1), we have two possible values: \(xy = -3\pi \approx -9.45\) and \(xy = \pi \approx 3.14\). Since both values are greater than -9.5, they both satisfy the condition in statement (2). Therefore, even with both statements, we cannot uniquely determine the value of \(xy\). Not sufficient.
Answer: E
Try NEW Algebra PS question.
13 Jul 2014, 00:15
Kudos
Bookmarks
For me - E
1. NS - because of values of x and y
2. NS - because even if i square both sides i get xy>9.5, so inconclusive
Combining 1 and 2 and solving for xy - again non conclusive. As x^2*y^2 > 9.5^2
So E, according to me...
Glad if someone can feed in the right solution. It got me worried for a bit.
1. NS - because of values of x and y
2. NS - because even if i square both sides i get xy>9.5, so inconclusive
Combining 1 and 2 and solving for xy - again non conclusive. As x^2*y^2 > 9.5^2
So E, according to me...
Glad if someone can feed in the right solution. It got me worried for a bit.
