GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 22 Jul 2018, 11:42

Close

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

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel

Is 2x+y>0?

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Expert Post
Math Revolution GMAT Instructor
User avatar
V
Joined: 16 Aug 2015
Posts: 5866
GMAT 1: 760 Q51 V42
GPA: 3.82
Premium Member
Is 2x+y>0?  [#permalink]

Show Tags

New post 28 Mar 2018, 01:59
00:00
A
B
C
D
E

Difficulty:

  35% (medium)

Question Stats:

71% (00:48) correct 29% (01:37) wrong based on 35 sessions

HideShow timer Statistics

[GMAT math practice question]

Is \(2x+y>0?\)

\(1) x+y>0\)
\(2) xy<0\)

_________________

MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
"Only $99 for 3 month Online Course"
"Free Resources-30 day online access & Diagnostic Test"
"Unlimited Access to over 120 free video lessons - try it yourself"

BSchool Forum Moderator
User avatar
G
Joined: 07 Jan 2016
Posts: 727
Location: India
GMAT 1: 710 Q49 V36
Reviews Badge
Re: Is 2x+y>0?  [#permalink]

Show Tags

New post 28 Mar 2018, 04:50
MathRevolution wrote:
[GMAT math practice question]

Is \(2x+y>0?\)

\(1) x+y>0\)
\(2) xy<0\)



1) x+y>0

2x+y may be lesser or greater as we don't know the signs

2)

xy<0
y is either positive or negative
x is either positive or negative
but both don't have same signs

insufficient


combining
as the x and y signs are not known

(E)
Expert Post
Math Revolution GMAT Instructor
User avatar
V
Joined: 16 Aug 2015
Posts: 5866
GMAT 1: 760 Q51 V42
GPA: 3.82
Premium Member
Re: Is 2x+y>0?  [#permalink]

Show Tags

New post 30 Mar 2018, 02:04
=>

Forget conventional ways of solving math questions. For DS problems, the VA (Variable Approach) method is the quickest and easiest way to find the answer without actually solving the problem. Remember that equal numbers of variables and independent equations ensure a solution.

Since we have 2 variables (x and y) and 0 equations, C is most likely to be the answer. So, we should consider conditions 1) & 2) together first. After comparing the number of variables and the number of equations, we can save time by considering conditions 1) & 2) together first.

Conditions 1) & 2) together:
If \(x = 2\), and \(y = -1\), then the answer is ‘yes’.
If\(x = -1\), and \(y = 2\), then the answer is ‘no’.

Since we don’t have a unique solution, both conditions together are not sufficient.

Therefore, the answer is E.

Answer: E

Normally, in problems which require 2 equations, such as those in which the original conditions include 2 variables, or 3 variables and 1 equation, or 4 variables and 2 equations, each of conditions 1) and 2) provide an additional equation. In these problems, the two key possibilities are that C is the answer (with probability 70%), and E is the answer (with probability 25%). Thus, there is only a 5% chance that A, B or D is the answer. This occurs in common mistake types 3 and 4. Since C (both conditions together are sufficient) is the most likely answer, we save time by first checking whether conditions 1) and 2) are sufficient, when taken together. Obviously, there may be cases in which the answer is A, B, D or E, but if conditions 1) and 2) are NOT sufficient when taken together, the answer must be E.
_________________

MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
"Only $99 for 3 month Online Course"
"Free Resources-30 day online access & Diagnostic Test"
"Unlimited Access to over 120 free video lessons - try it yourself"

Re: Is 2x+y>0? &nbs [#permalink] 30 Mar 2018, 02:04
Display posts from previous: Sort by

Is 2x+y>0?

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  

Events & Promotions

PREV
NEXT


GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.