|
|
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.
11 Sep 2017, 00:28
Kudos
Bookmarks
C
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
35%
(medium)
Question Stats:
70% (01:37) correct
30%
(02:27)
wrong
based on 53
sessions
History
Date
Time
Result
Not Attempted Yet
What is the value of x^2 – y^2 ?
(1) \(2xy = x + y\)
(2) \(x^2y – xy^2 = 1\)
(1) \(2xy = x + y\)
(2) \(x^2y – xy^2 = 1\)
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
11 Sep 2017, 01:08
Kudos
Bookmarks
It's a C ...
Statement 1: not sufficient. We don't know the value of x-y.
Statement 2: not sufficient. We don't know the value of X+y.
Statement 1 and 2. We have the individual values of X+y and x-y.
It gives a value of 1.
Sent from my Lenovo TAB S8-50LC using GMAT Club Forum mobile app
Statement 1: not sufficient. We don't know the value of x-y.
Statement 2: not sufficient. We don't know the value of X+y.
Statement 1 and 2. We have the individual values of X+y and x-y.
It gives a value of 1.
Sent from my Lenovo TAB S8-50LC using GMAT Club Forum mobile app
12 Sep 2017, 09:31
Kudos
Bookmarks
Stem : x^2 - y^2 = (x+y)(x-y)
S1 : 2xy = x+y Not Sufficient
S2 : x^2y-xy^2 = 1 ---> xy(x-y) = 1.
So both, xy = (x-y) = 1. Again Not sufficient.
S1 + S2 = as xy = 1, x+y = 2xy = 2(1) = 2 ---> x+y = 2
and x-y = 1. So (x+y)(x-y) = 2*1 = 2.
Hence C is the answer
S1 : 2xy = x+y Not Sufficient
S2 : x^2y-xy^2 = 1 ---> xy(x-y) = 1.
So both, xy = (x-y) = 1. Again Not sufficient.
S1 + S2 = as xy = 1, x+y = 2xy = 2(1) = 2 ---> x+y = 2
and x-y = 1. So (x+y)(x-y) = 2*1 = 2.
Hence C is the answer
