Author 
Message 
TAGS:

Hide Tags

Manager
Joined: 10 Sep 2010
Posts: 128

If y is an integer and y=x+x, is y=0? [#permalink]
Show Tags
14 Dec 2010, 22:03
2
This post received KUDOS
2
This post was BOOKMARKED
Question Stats:
52% (01:58) correct
48% (00:53) wrong based on 195 sessions
HideShow timer Statistics
If y is an integer and y=x+x, is y=0? (1) x<0 (2) y<1
Official Answer and Stats are available only to registered users. Register/ Login.



Director
Joined: 03 Sep 2006
Posts: 871

Re: tricky q from GMATPrep2 [#permalink]
Show Tags
14 Dec 2010, 22:39
1
This post received KUDOS
Each of (1) and (2) are sufficient to answer the question. Thus the answer should be "D". From(1), any value of X<0, whether it's integer or fraction will lead to Y = 0 because the mode function will result in positive value and positive value added to same negative value will result in Zero. From (2), We can have Y as negative Integer ( 1,2....) if and only if the Right hand side of equation is different. It's just adding the same X and it can't lead to the negative value.
Yes it can definitely lead to the Zero.
Thus Answer should be D.
You can plug and play certain values ( numbers ) in order to verify the above.



Math Expert
Joined: 02 Sep 2009
Posts: 39593

Re: tricky q from GMATPrep2 [#permalink]
Show Tags
15 Dec 2010, 01:50



Intern
Joined: 23 Sep 2015
Posts: 48

Re: If y is an integer and y=x+x, is y=0? [#permalink]
Show Tags
08 Oct 2016, 05:00
1
This post received KUDOS
abhimahna wrote: nishantdoshi wrote: hey t hanks for the reply
When we say x = x, we mean x will hold a negative value which when multiplied by ve sign before will give a positive result. NEVER EVER take the values of mod like the way you have taken. I would suggest go through the mod concepts again.
i couldnt understand the above sentence
but my point is when we take x as 2,we get, y=22 => y=22 just like we do in the "Critical Points method" (if we get ve value inside the mod we mult. the mod with the ve sign.)
please give me detailed explanation if i'm wrong.please. No Dude, your reasoning is 100% incorrect. As I said above x is always positive, so 2 is always 2. Note that MOD means MAGNITUTE irrespective of sign. Now, I can confidently say you are not aware of Mod concept used in mathematics. Please go through the below link and try solving as many questions as you could. http://magoosh.com/gmat/2012/gmatmath ... tevalues/thanks a lot. and can i pm you for doubts in other topics?



Manager
Joined: 10 Sep 2010
Posts: 128

Re: tricky q from GMATPrep2 [#permalink]
Show Tags
14 Dec 2010, 23:07
I got it. thanks I just forgot that "y" is an integer. For some reason I thought that "y" can be 0<y<1. Thanks. I need to be more careful.



Senior Manager
Status: Bring the Rain
Joined: 17 Aug 2010
Posts: 401
Location: United States (MD)
Concentration: Strategy, Marketing
Schools: Michigan (Ross)  Class of 2014
GPA: 3.13
WE: Corporate Finance (Aerospace and Defense)

Re: tricky q from GMATPrep2 [#permalink]
Show Tags
15 Dec 2010, 07:33
I orginially had this as A, because I didn't read the question thoroughly to see y was an integer. just goes to show how easy it is to miss something if you are going too fast.
_________________
Go Blue!
GMAT Club Premium Membership  big benefits and savings



Joined: 31 Dec 1969
Location: Russian Federation
Concentration: Entrepreneurship, International Business
GMAT 3: 740 Q40 V50 GMAT 4: 700 Q48 V38 GMAT 5: 710 Q45 V41 GMAT 6: 680 Q47 V36 GMAT 9: 740 Q49 V42 GMAT 11: 500 Q47 V33 GMAT 14: 760 Q49 V44
WE: Supply Chain Management (Energy and Utilities)

Re: tricky q from GMATPrep2 [#permalink]
Show Tags
16 Dec 2010, 01:33
tfincham86 wrote: I orginially had this as A, because I didn't read the question thoroughly to see y was an integer.
just goes to show how easy it is to miss something if you are going too fast. Same mistake... It kills me !!!!!!!!!



Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 7439
Location: Pune, India

Re: tricky q from GMATPrep2 [#permalink]
Show Tags
16 Dec 2010, 06:51
Fijisurf wrote: I am sure it is posted somewhere on the forum already , I just can't find it.
If y is an integer and y=x+x, is y=0?
(1)x<0 (2)y<1 A word of caution: When you read "If y is an integer and y=x+x", analyze it there and then. y can be a positive integer when x is positive, y will be 0 when x is negative and y will be 0 when x is 0." Another important point to note here: When the author puts in extra effort to write "y is an integer" rather than "x and y are integers" , take special note that x may not be an integer. Not that it matters very much here but in many questions such a statement will have special significance.
_________________
Karishma Veritas Prep  GMAT Instructor My Blog
Get started with Veritas Prep GMAT On Demand for $199
Veritas Prep Reviews



Intern
Joined: 19 Sep 2010
Posts: 14

please explain, why not D why only B [#permalink]
Show Tags
25 Feb 2011, 08:26
Q19: If y is an integer and y = !x! + x, is y = 0? (1) x < 0 (2) y < 1



Math Expert
Joined: 02 Sep 2009
Posts: 39593

Re: please explain, why not D why only B [#permalink]
Show Tags
25 Feb 2011, 09:02



GMAT Club Legend
Joined: 09 Sep 2013
Posts: 15918

Re: If y is an integer and y=x+x, is y=0? [#permalink]
Show Tags
06 Feb 2014, 04:45
Hello from the GMAT Club BumpBot! Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up  doing my job. I think you may find it valuable (esp those replies with Kudos). Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
GMAT Books  GMAT Club Tests  Best Prices on GMAT Courses  GMAT Mobile App  Math Resources  Verbal Resources



Intern
Joined: 01 Aug 2006
Posts: 35

Re: If y is an integer and y=x+x, is y=0? [#permalink]
Show Tags
07 Feb 2014, 17:23
If y is an integer and y = x + x, is y = 0? y = 0, when x < 0; y = 2x, when x >=0 (1) x < 0 => y = 0 (2) y < 1 > Because y is an integer, y has to be zero (y cannot be a negative integer because the least value of y is zero).
D



GMAT Club Legend
Joined: 09 Sep 2013
Posts: 15918

Re: If y is an integer and y=x+x, is y=0? [#permalink]
Show Tags
30 Jun 2016, 03:23
Hello from the GMAT Club BumpBot! Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up  doing my job. I think you may find it valuable (esp those replies with Kudos). Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
GMAT Books  GMAT Club Tests  Best Prices on GMAT Courses  GMAT Mobile App  Math Resources  Verbal Resources



Intern
Joined: 23 Sep 2015
Posts: 48

Re: If y is an integer and y=x+x, is y=0? [#permalink]
Show Tags
08 Oct 2016, 03:35
Bunuel wrote: Fijisurf wrote: I am sure it is posted somewhere on the forum already , I just can't find it.
If y is an integer and y=x+x, is y=0?
(1)x<0 (2)y<1 If y is an integer and y = x + x, is y = 0? (1) x < 0 (2) y < 1 Note: as \(y=x+x\) then \(y\) is never negative. If \(x>{0}\) then \(y=x+x=2x>0\) and if \(x\leq{0}\) (when x is negative or zero) then \(y=x+x=0\). please help! (1) \(x<0\) > \(y=x+x=x+x=0\). Sufficient. (2) \(y<1\), as we concluded y is never negative, and we are given that \(y\) is an integer, hence \(y=0\). Sufficient. Answer: D.Also discussed in Inequality and absolute value questions from my collection: inequalityandabsolutevaluequestionsfrommycollection86939.htmlHope it's clear. the only place i'm stuck is if \(x\leq{0}\) (when x is negative or zero) then \(y=x+x=0\) if x is negative why arent we taking the other x as negative:\(y=xx=2x\)



Math Expert
Joined: 02 Sep 2009
Posts: 39593

Re: If y is an integer and y=x+x, is y=0? [#permalink]
Show Tags
08 Oct 2016, 03:48
nishantdoshi wrote: Bunuel wrote: Fijisurf wrote: I am sure it is posted somewhere on the forum already , I just can't find it.
If y is an integer and y=x+x, is y=0?
(1)x<0 (2)y<1 If y is an integer and y = x + x, is y = 0? (1) x < 0 (2) y < 1 Note: as \(y=x+x\) then \(y\) is never negative. If \(x>{0}\) then \(y=x+x=2x>0\) and if \(x\leq{0}\) (when x is negative or zero) then \(y=x+x=0\). please help! (1) \(x<0\) > \(y=x+x=x+x=0\). Sufficient. (2) \(y<1\), as we concluded y is never negative, and we are given that \(y\) is an integer, hence \(y=0\). Sufficient. Answer: D.Also discussed in Inequality and absolute value questions from my collection: inequalityandabsolutevaluequestionsfrommycollection86939.htmlHope it's clear. the only place i'm stuck is if \(x\leq{0}\) (when x is negative or zero) then \(y=x+x=0\) if x is negative why arent we taking the other x as negative:\(y=xx=2x\) Knowing that x is a negative number does not mean that you should replace it with x, this just does not make any sense.
_________________
New to the Math Forum? Please read this: 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? Extrahard Quant Tests with Brilliant Analytics



BSchool Forum Moderator
Status: Aiming 800 Q51 V51
Joined: 18 Jul 2015
Posts: 1840
Location: India
Concentration: General Management, International Business
GMAT 1: 670 Q50 V32 GMAT 2: 700 Q50 V34
GPA: 3.65
WE: Brand Management (Health Care)

Re: If y is an integer and y=x+x, is y=0? [#permalink]
Show Tags
08 Oct 2016, 04:00
nishantdoshi wrote: Bunuel wrote: Fijisurf wrote: I am sure it is posted somewhere on the forum already , I just can't find it.
If y is an integer and y=x+x, is y=0?
(1)x<0 (2)y<1 If y is an integer and y = x + x, is y = 0? (1) x < 0 (2) y < 1 Note: as \(y=x+x\) then \(y\) is never negative. If \(x>{0}\) then \(y=x+x=2x>0\) and if \(x\leq{0}\) (when x is negative or zero) then \(y=x+x=0\). please help! (1) \(x<0\) > \(y=x+x=x+x=0\). Sufficient. (2) \(y<1\), as we concluded y is never negative, and we are given that \(y\) is an integer, hence \(y=0\). Sufficient. Answer: D.Also discussed in Inequality and absolute value questions from my collection: inequalityandabsolutevaluequestionsfrommycollection86939.htmlHope it's clear. the only place i'm stuck is if \(x\leq{0}\) (when x is negative or zero) then \(y=x+x=0\) if x is negative why arent we taking the other x as negative:\(y=xx=2x\) No, you are missing something here. We are given y = x + x, take the value of x as 2 and see the result. Note that x is always positive, When we say x = x, we mean x will hold a negative value which when multiplied by ve sign before will give a positive result. NEVER EVER take the values of mod like the way you have taken. I would suggest go through the mod concepts again.
_________________
Good Luck



Intern
Joined: 23 Sep 2015
Posts: 48

Re: If y is an integer and y=x+x, is y=0? [#permalink]
Show Tags
08 Oct 2016, 04:42
hey t hanks for the reply
When we say x = x, we mean x will hold a negative value which when multiplied by ve sign before will give a positive result. NEVER EVER take the values of mod like the way you have taken. I would suggest go through the mod concepts again.
i couldnt understand the above sentence
but my point is when we take x as 2,we get, y=22 => y=22 just like we do in the "Critical Points method" (if we get ve value inside the mod we mult. the mod with the ve sign.)
please give me detailed explanation if i'm wrong.please.



BSchool Forum Moderator
Status: Aiming 800 Q51 V51
Joined: 18 Jul 2015
Posts: 1840
Location: India
Concentration: General Management, International Business
GMAT 1: 670 Q50 V32 GMAT 2: 700 Q50 V34
GPA: 3.65
WE: Brand Management (Health Care)

If y is an integer and y=x+x, is y=0? [#permalink]
Show Tags
08 Oct 2016, 04:51
nishantdoshi wrote: hey t hanks for the reply
When we say x = x, we mean x will hold a negative value which when multiplied by ve sign before will give a positive result. NEVER EVER take the values of mod like the way you have taken. I would suggest go through the mod concepts again.
i couldnt understand the above sentence
but my point is when we take x as 2,we get, y=22 => y=22 just like we do in the "Critical Points method" (if we get ve value inside the mod we mult. the mod with the ve sign.)
please give me detailed explanation if i'm wrong.please. No Dude, your reasoning is 100% incorrect. As I said above x is always positive, so 2 is always 2. Note that MOD means MAGNITUTE irrespective of sign. Now, I can confidently say you are not aware of Mod concept used in mathematics. Please go through the below link and try solving as many questions as you could. http://magoosh.com/gmat/2012/gmatmath ... tevalues/
_________________
Good Luck



Intern
Joined: 03 Oct 2016
Posts: 3

Re: If y is an integer and y=x+x, is y=0? [#permalink]
Show Tags
08 Oct 2016, 05:16
Break into 2 cases a) x>0 then y = 2x, and y >=1 as y is an integer
b) x<= 0 then y = 0
therefore 1) is sufficient as for x <0, y is 0 2) is sufficient as only possible value of y <1 is 0, coming from the case b).
Hence, an is D



CEO
Joined: 17 Jul 2014
Posts: 2524
Location: United States (IL)
Concentration: Finance, Economics
GPA: 3.92
WE: General Management (Transportation)

Re: If y is an integer and y=x+x, is y=0? [#permalink]
Show Tags
10 Nov 2016, 16:38
Fijisurf wrote: If y is an integer and y=x+x, is y=0?
(1) x<0 (2) y<1 haha, what a classic trap! i knew it when i saw 50% correct rate... 1. sufficient. x is negative, therefore y=0 2. y<1. sufficient. y must be zero. y can't be a decimal, since we are given the fact that y is an integer. answer is D.




Re: If y is an integer and y=x+x, is y=0?
[#permalink]
10 Nov 2016, 16:38








Similar topics 
Author 
Replies 
Last post 
Similar Topics:




If x, y ≠ 0, is x/y an integer?

Bunuel 
3 
20 May 2017, 04:18 



If x and y are positive integers, does x–y = 0? (1)

Bhalla 
7 
03 Mar 2017, 06:40 



If y is an integer, is y = 0? (1) When y is divided by an even intege

Bunuel 
1 
12 Dec 2016, 14:54 

5


If n is a positive integer and y ≠ 0, what is the value of

mvictor 
6 
24 Nov 2016, 10:19 

25


If y is an integer and y = x + x, is y = 0?

devinawilliam83 
9 
02 May 2017, 21:15 



