|
|
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.
C
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
15%
(low)
Question Stats:
81% (01:11) correct
19%
(01:26)
wrong
based on 137
sessions
History
Date
Time
Result
Not Attempted Yet
If \(xy\neq{0}\), is 1/x + 1/y = 4 ?
(1) 4 - 1/y = 2.5
(2) 5x = 2
(1) 4 - 1/y = 2.5
(2) 5x = 2
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
31 May 2013, 05:55
Kudos
Bookmarks
buguy7
If \(xy\neq{0}\), is 1/x + 1/y = 4 ?
(1) 4 - 1/y = 2.5 --> \(4y-1=2.5y\) --> \(y=\frac{2}{3}\). We don't know the value of x to answer the question whether \(\frac{1}{x} + \frac{3}{2} = 4\). Not sufficient.
(2) 5x = 2 --> \(y=\frac{2}{5}\). We don't know the value of y to answer the question whether \(\frac{5}{2} + \frac{1}{y} = 4\). Not sufficient.
(1)+(2) We know both the values of x and y, thus we can answer the question. Sufficient.
Answer: C.
P.S. Please read carefully and follow: rules-for-posting-please-read-this-before-posting-133935.html Pay attention to the rule #3. Thank you.
P.P.S. Please hide OA's under the spoiler.
12 Jun 2013, 23:30
Kudos
Bookmarks
buguy7
Responding to a pm:
Quote:
The confusion you are facing is regarding what is given and what is asked.
The question stem tells you that xy is not 0 i.e. neither x nor y is 0.
It is not given that 1/x + 1/y is equal to 4. That is the question: Is 1/x + 1/y equal to 4?
Statement 1 tells you that 4 - 1/y = 2.5
i.e. it tells you that 2.5 + 1/y = 4
So you have only 2 pieces of info:
x and y are not 0
2.5 + 1/y = 4
The question is: Is 1/x + 1/y equal to 4?
Can you answer it with a yes or no? No, you cannot answer it. All you know is that 2.5 + 1/y is equal to 4. You don't know whether 1/x + 1/y is equal to 4. Only if you also knew whether 1/x = 2.5, then you can say yes/no.
Hence you need statement II as well to answer the question and the answer is (C).
