It is currently 18 Jan 2018, 12:04

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

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

If x and y are positive, is xy > x + y?

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

Hide Tags

Director
Director
User avatar
B
Status: I don't stop when I'm Tired,I stop when I'm done
Joined: 11 May 2014
Posts: 564

Kudos [?]: 3283 [0], given: 220

Location: Bangladesh
Concentration: Finance, Leadership
GPA: 2.81
WE: Business Development (Real Estate)
If x and y are positive, is xy > x + y? [#permalink]

Show Tags

New post 01 Jul 2016, 04:53
1
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  35% (medium)

Question Stats:

74% (01:18) correct 26% (01:20) wrong based on 244 sessions

HideShow timer Statistics

If x and y are positive, is xy > x + y?

(1) x < y
(2) 2 < x

OG Q 2017 New Question(Book Question: 199)
[Reveal] Spoiler: OA

_________________

Md. Abdur Rakib

Please Press +1 Kudos,If it helps
Sentence Correction-Collection of Ron Purewal's "elliptical construction/analogies" for SC Challenges

Kudos [?]: 3283 [0], given: 220

Senior Manager
Senior Manager
avatar
Joined: 02 Mar 2012
Posts: 356

Kudos [?]: 94 [0], given: 4

Schools: Schulich '16
Re: If x and y are positive, is xy > x + y? [#permalink]

Show Tags

New post 01 Jul 2016, 07:06
given x and y positive

if we take x,y<1 then statement doesn't hold if x,y>1 then holds.

1) not suff for above explanation
2)no info about y

we know x>2 and so is y so 1+2 is suff

Kudos [?]: 94 [0], given: 4

VP
VP
avatar
P
Joined: 26 Mar 2013
Posts: 1362

Kudos [?]: 322 [0], given: 170

Reviews Badge CAT Tests
Re: If x and y are positive, is xy > x + y? [#permalink]

Show Tags

New post 02 Jul 2016, 08:53
AbdurRakib wrote:
If x and y are positive,is xy>x+y?

(1) x<y
(2) 2<x

OG Q 2017 New Question(Book Question: 199)



IS xy>x+y


Fact 1) x<y

Put x=1/2, Y=2 1>2.5 Answer is NO
Put x= 3, Y=4 12>7 Answer is YES
Insuff


Fact 2) X>2 Clearly Insuff


Combining 1 & 2

Take example above when x= 3, Y=4
Another example x=5/2 , Y=4
Suff.

Answer is C

Kudos [?]: 322 [0], given: 170

Intern
Intern
avatar
B
Joined: 30 May 2017
Posts: 1

Kudos [?]: 0 [0], given: 3

Re: If x and y are positive, is xy > x + y? [#permalink]

Show Tags

New post 04 Jan 2018, 00:19
Why should the answer be not B because, if we take x = 3 and y = 4, the statement is sufficient (if first condition is taken into consideration) and if we take x = 5 and y = 2 then also the statement is sufficient (if first taken not taken into consideration) so having condition 1 is not necessary.

Can anyone respond to this ?

Kudos [?]: 0 [0], given: 3

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 43323

Kudos [?]: 139428 [0], given: 12790

Re: If x and y are positive, is xy > x + y? [#permalink]

Show Tags

New post 04 Jan 2018, 00:31
sagargoyal wrote:
Why should the answer be not B because, if we take x = 3 and y = 4, the statement is sufficient (if first condition is taken into consideration) and if we take x = 5 and y = 2 then also the statement is sufficient (if first taken not taken into consideration) so having condition 1 is not necessary.

Can anyone respond to this ?


Two examples, are not enough to prove sufficiency. What if x = 1 and y = 1? For (2), there are infinitely many pairs which give a NO answer to the question as well as there are infinitely many pairs which give an YES answer to the question.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Kudos [?]: 139428 [0], given: 12790

Expert Post
Math Revolution GMAT Instructor
User avatar
D
Joined: 16 Aug 2015
Posts: 4683

Kudos [?]: 3313 [0], given: 0

GPA: 3.82
Premium Member
If x and y are positive, is xy > x + y? [#permalink]

Show Tags

New post 09 Jan 2018, 18:17
AbdurRakib wrote:
If x and y are positive, is xy > x + y?

(1) x < y
(2) 2 < x

OG Q 2017 New Question(Book Question: 199)



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.

The first step of the VA (Variable Approach) method is to modify the original condition and the question, and then recheck the question.

xy > x + y
⇔ xy - x - y > 0
⇔ xy - x - y + 1 > 1
⇔ (x-1)(y-1) > 1
⇔ x > 1, y > 1 or 0 < x < 1, 0 < y < 1?

Since we have 2 variables (x and y) and 0 equations,C is most likely to be the answer. So, we should consider 1) & 2) first.

Conditions 1) & 2):
Since x > 2, y > x > 2 or y > 2, both conditions together are sufficient.

Since this is an inequality question (one of the key question areas), we should also consider choices A and B by CMT(Common Mistake Type) 4(A).

Condition 1)
x = 2, y = 3: Yes
x = 1/2, y = 1: No
The condition 1) is not sufficient.

Condition 2)
x = 3, y = 4: Yes
x = 3, y = 1/2: No
The condition 2) is not sufficient.

Therefore, the answer is C.
_________________

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.
Find a 10% off coupon code for GMAT Club members.
“Receive 5 Math Questions & Solutions Daily”
Unlimited Access to over 120 free video lessons - try it yourself
See our Youtube demo

Kudos [?]: 3313 [0], given: 0

If x and y are positive, is xy > x + y?   [#permalink] 09 Jan 2018, 18:17
Display posts from previous: Sort by

If x and y are positive, is xy > x + y?

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


GMAT Club MBA Forum Home| About| Terms and Conditions| 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®.