Check GMAT Club Decision Tracker for the Latest School Decision Releases https://gmatclub.com/AppTrack

 It is currently 23 May 2017, 22:07

### 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

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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# If @ represents one of the operations +, -, and x, is k@(l+m

Author Message
TAGS:

### Hide Tags

Manager
Joined: 02 Dec 2012
Posts: 178
Followers: 6

Kudos [?]: 2689 [3] , given: 0

If @ represents one of the operations +, -, and x, is k@(l+m [#permalink]

### Show Tags

14 Dec 2012, 07:13
3
KUDOS
16
This post was
BOOKMARKED
00:00

Difficulty:

35% (medium)

Question Stats:

69% (02:19) correct 31% (01:28) wrong based on 919 sessions

### HideShow timer Statistics

If @ represents one of the operations +, -, and x, is k@(l+m)=(k@l)+(k@m) for all numbers k, l,and m?

(1) k@1 is not equal to 1@k for some numbers k.
(2) @ represents subtraction.
[Reveal] Spoiler: OA
Math Expert
Joined: 02 Sep 2009
Posts: 38846
Followers: 7719

Kudos [?]: 105942 [4] , given: 11602

Re: If @ represents one of the operations +, -, and x, is k@(l+m [#permalink]

### Show Tags

14 Dec 2012, 07:27
4
KUDOS
Expert's post
1
This post was
BOOKMARKED
If @ represents one of the operations +, -, and x, is k@(l+m)=(k@l)+(k@m) for all numbers k, l,and m?

(1) k@1 is not equal to 1@k for some numbers k. @ is neither addition (as $$k+1=1+k$$) nor multiplication (as $$k*1=1*k$$), thus @ represents subtraction. Knowing that we can determine whether $$k-(l+m)=(k-l)+(k-m)$$ for all numbers k, l,and m. Sufficient.

(2) @ represents subtraction. The same here. Sufficient.

_________________
Intern
Joined: 16 Apr 2009
Posts: 16
Followers: 0

Kudos [?]: 14 [0], given: 5

Re: If @ represents one of the operations +, -, and x, is k@(l+m [#permalink]

### Show Tags

16 Dec 2012, 12:04
Bunuel wrote:
If @ represents one of the operations +, -, and x, is k@(l+m)=(k@l)+(k@m) for all numbers k, l,and m?

(1) k@1 is not equal to 1@k for some numbers k. @ is neither addition (as $$k+1=1+k$$) nor multiplication (as $$k*1=1*k$$), thus @ represents subtraction. Knowing that we can determine whether $$k-(l+m)=(k-l)+(k-m)$$ for all numbers k, l,and m. Sufficient.

(2) @ represents subtraction. The same here. Sufficient.

Dear Bunnel,
I would like to understand the above question first..
If we take the @ as subtraction from statement 1 and 2 then the equation stands as $$k-l-m=2k-l-m$$, which is not equal in both the side.

I was wondering whether the question asks about the operation of the @ sign, which makes the equation of k@(l+m)=(k@l)+(k@m) okay from both end.

Thanks
Math Expert
Joined: 02 Sep 2009
Posts: 38846
Followers: 7719

Kudos [?]: 105942 [0], given: 11602

Re: If @ represents one of the operations +, -, and x, is k@(l+m [#permalink]

### Show Tags

17 Dec 2012, 00:07
Drik wrote:
Bunuel wrote:
If @ represents one of the operations +, -, and x, is k@(l+m)=(k@l)+(k@m) for all numbers k, l,and m?

(1) k@1 is not equal to 1@k for some numbers k. @ is neither addition (as $$k+1=1+k$$) nor multiplication (as $$k*1=1*k$$), thus @ represents subtraction. Knowing that we can determine whether $$k-(l+m)=(k-l)+(k-m)$$ for all numbers k, l,and m. Sufficient.

(2) @ represents subtraction. The same here. Sufficient.

Dear Bunnel,
I would like to understand the above question first..
If we take the @ as subtraction from statement 1 and 2 then the equation stands as $$k-l-m=2k-l-m$$, which is not equal in both the side.

I was wondering whether the question asks about the operation of the @ sign, which makes the equation of k@(l+m)=(k@l)+(k@m) okay from both end.

Thanks

No, the question asks: "is k@(l+m)=(k@l)+(k@m) for ALL numbers k, l,and m", where @ represents one of the operations +, -, and x.
_________________
Manager
Joined: 18 Dec 2012
Posts: 96
Location: India
Concentration: General Management, Strategy
GMAT 1: 660 Q49 V32
GMAT 2: 530 Q37 V25
GPA: 3.32
WE: Manufacturing and Production (Manufacturing)
Followers: 1

Kudos [?]: 43 [1] , given: 34

Re: If @ represents one of the operations +, -, and x, is k@(l+m [#permalink]

### Show Tags

01 Aug 2013, 10:31
1
KUDOS

If we take k=l=m=0 & k=1, l=2, m=3, from statement 1 we will get both "yes" or "no". Similarly Statement 2 also gives the same result.

The question doesn't specify anything about k,l,m

Could you explain?
_________________

I'm telling this because you don't get it. You think you get it which is not the same as actually getting it. Get it?

Math Expert
Joined: 02 Sep 2009
Posts: 38846
Followers: 7719

Kudos [?]: 105942 [1] , given: 11602

Re: If @ represents one of the operations +, -, and x, is k@(l+m [#permalink]

### Show Tags

09 Aug 2013, 02:35
1
KUDOS
Expert's post
5
This post was
BOOKMARKED
Qoofi wrote:

If we take k=l=m=0 & k=1, l=2, m=3, from statement 1 we will get both "yes" or "no". Similarly Statement 2 also gives the same result.

The question doesn't specify anything about k,l,m

Could you explain?

From (1) we got that @ is subtraction. So, the question becomes: is k-(l+m)=(k-l)+(k-m) for ALL NUMBERS k, l,and m? This equation holds if k=0. Therefore the equation does NOT hold true for ALL NUMBERS (it holds if k=0).

The same applies to the second statement.

Similar questions to practice:
if-represents-one-of-the-operations-and-x-is-k-l-m-144138.html
if-the-operation-is-one-of-the-four-arithmetic-operations-101283.html
if-the-operation-is-one-of-the-four-arithmetic-operations-93966.html
the-symbol-represents-one-of-the-four-arithmetic-operation-107575.html
if-represents-one-of-the-operations-and-is-a-101337.html
the-operation-x-n-for-all-positive-integers-greater-than-99064.html

Hope it helps.
_________________
Intern
Joined: 09 Sep 2013
Posts: 19
Followers: 1

Kudos [?]: 1 [0], given: 7

Re: If @ represents one of the operations +, -, and x, is k@(l+m [#permalink]

### Show Tags

12 Oct 2013, 12:20
The way I approached this question was basically "is @ multiplication"?

That is the only symbol that will make the equation in the question stem equal.

The first statement tells us indeed that @ is not multiplication or even addition. The only other option is subtraction...so we have our answer and it is not multiplication. Sufficient.

The second statement tells us @ is subtraction. Ok so we know it is not multiplication. Sufficient.
Intern
Joined: 17 Jun 2013
Posts: 1
GMAT Date: 03-19-2014
Followers: 0

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

Re: If @ represents one of the operations +, -, and x, is k@(l+m [#permalink]

### Show Tags

16 Nov 2013, 21:37
The way i see the question,
k o (l +m) = (k o l) + (k o m) is only true where o is x(multiplication)
for o = + and o = -, it's not true.

1. k o 1 not equal to 1 o k. This statement is true only when o is subtraction (-). But we know that the above statement is valid only for multiplication. So this option is SUFFICIENT.
2. o represents subtraction . This statement is SUFFICIENT , as we know that the question is valid only for multiplication.
Manager
Joined: 23 Apr 2012
Posts: 55
GMAT 1: 690 Q49 V34
Followers: 1

Kudos [?]: 20 [1] , given: 2

Re: If @ represents one of the operations +, -, and x, is k@(l+m [#permalink]

### Show Tags

16 Nov 2013, 23:24
1
KUDOS
If @ represents one of the operations +, -, and x, is k@(l+m)=(k@l)+(k@m) for all numbers k, l,and m?

(1) k@1 is not equal to 1@k for some numbers k.
(2) @ represents subtraction.

The answer to this question could be a yes or a no. If we can somehow say for sure - yes or no, then we know the option is sufficient.
2) clearly says @ is subtractn. Therefore, the equation in the question is NOT true for all nos. k,l,m. SUFFICIENT.

1)k@1 != 1@k implies that @ s not x . This could be + since if k is neg, -k+1 is not equal to 1-(-k)
This could be - since k-1 != 1-k.
substituting in the question, for +: is k+(l+m)=(k+l) + (k+m). NO.
for - : is k-(l-m)= (k-l) + (k-m) . NO.

There the equation is NOT true for all nos. SUFFICIENT.

D it is!
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 15412
Followers: 648

Kudos [?]: 206 [0], given: 0

Re: If @ represents one of the operations +, -, and x, is k@(l+m [#permalink]

### Show Tags

27 Nov 2014, 01:08
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.
_________________
Intern
Joined: 09 Feb 2013
Posts: 18
Followers: 0

Kudos [?]: 0 [0], given: 50

Re: If represents one of the operations +, -, and x, is k(l+m [#permalink]

### Show Tags

13 Jul 2015, 09:07
St1 : @ is substraction

if we take K=5, l=3, m=2
Then 0 is not equal to 5....as per question stem answer is NO.

If we take K=0,l=1,m= 2

Then -3= -3....so answer is YES

Since we get yes and no both....shouldn't this statement be insufficient ?

Where am I doing the mistake ?
Intern
Status: Time to Improvize
Joined: 02 Jun 2015
Posts: 5
GMAT 1: 720 Q50 V38
Followers: 0

Kudos [?]: 7 [0], given: 7

If represents one of the operations +, -, and x, is k(l+m [#permalink]

### Show Tags

17 Aug 2015, 23:16
1
This post was
BOOKMARKED
Hi Guys,

Please correct me if I'm wrong, but this seems to be a wrong answer for the below question -

Refer the attachment.

I think the answer should be E as the equation has to be true for all numbers x,y, and z.
x,y and z considered non-zero give the answer as NO for a "subtraction" sign.
x,y and z ,all considered zero give the answer as YES for the same "subtraction" sign.
Attachments

File comment: This is a question.

GMAT Test Prep Wrong Answer.PNG [ 99.24 KiB | Viewed 4824 times ]

Last edited by Engr2012 on 23 Aug 2015, 05:18, edited 2 times in total.
EMPOWERgmat Instructor
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 9109
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: 340 Q170 V170
Followers: 440

Kudos [?]: 2858 [0], given: 169

Re: If represents one of the operations +, -, and x, is k(l+m)=(kl)+(k [#permalink]

### Show Tags

18 Aug 2015, 21:38
Hi nuttyaks,

You'll likely get a much bigger response if you post your question in the DS Forum:

gmat-data-sufficiency-ds-141/

Also, when you post it, you should physically type out the question (not post a screen-grab; that tends to be frowned-upon).

GMAT assassins aren't born, they're made,
Rich
_________________

760+: Learn What GMAT Assassins Do to Score at the Highest Levels
Contact Rich at: Rich.C@empowergmat.com

# Rich Cohen

Co-Founder & GMAT Assassin

# Special Offer: Save \$75 + GMAT Club Tests

60-point improvement guarantee
www.empowergmat.com/

***********************Select EMPOWERgmat Courses now include ALL 6 Official GMAC CATs!***********************

Intern
Status: Time to Improvize
Joined: 02 Jun 2015
Posts: 5
GMAT 1: 720 Q50 V38
Followers: 0

Kudos [?]: 7 [0], given: 7

Re: If represents one of the operations +, -, and x, is k(l+m)=(kl)+(k [#permalink]

### Show Tags

21 Aug 2015, 23:50
Thanks for the information.
Going forward I'll post them according to the rules listed
Director
Affiliations: GMATQuantum
Joined: 19 Apr 2009
Posts: 597
Followers: 116

Kudos [?]: 443 [0], given: 16

Re: If represents one of the operations +, -, and x, is k(l+m)=(kl)+(k [#permalink]

### Show Tags

23 Aug 2015, 00:23
Hi nuttyaks,

This is a tricky question that troubles a lot of students.

Based on statement 1, the symbol {o} has to be equal to subtraction, because in the case of addition and multiplication the operation k{o}1 is equal to 1{o}k for all all numbers. So the conclusion from statement 1 is that the symbol stands for only subtraction.

Now if we go back to the original question in the main stem, which asks if Does k{o}(l+m) = (k{o}l) + (k{o}m) for all numbers k, l, and m? meaning is the answer to this question a definite Yes or No. If the {o} stands for subtraction then the condition k-{l+m} is not equal to (k-l) + (k-m) for all numbers. It may hold true for k=l=m=0, but we need to answer the question if it holds true for all possible values of k, l, and m, and the answer to that is a definite No, which makes it sufficient.

Cheers,
Dabral
Math Forum Moderator
Joined: 20 Mar 2014
Posts: 2644
Concentration: Finance, Strategy
Schools: Kellogg '18 (M)
GMAT 1: 750 Q49 V44
GPA: 3.7
WE: Engineering (Aerospace and Defense)
Followers: 128

Kudos [?]: 1470 [0], given: 789

If represents one of the operations +, -, and x, is k(l+m [#permalink]

### Show Tags

23 Aug 2015, 05:06
nuttyaks wrote:
Hi Guys,

Please correct me if I'm wrong, but this seems to be a wrong answer for the below question -

Refer the attachment.

I think the answer should be E as the equation has to be true for all numbers x,y, and z.
x,y and z considered non-zero give the answer as NO for a "subtraction" sign.
x,y and z ,all considered zero give the answer as YES for the same "subtraction" sign.

You must type in the question completely with answer choices provided. Do not post pictures in lieu of the question.

List of all OG quant questions solved: the-official-guide-quantitative-question-directory-143450.html

Search for question before posting a new question.
_________________

Thursday with Ron updated list as of July 1st, 2015: http://gmatclub.com/forum/consolidated-thursday-with-ron-list-for-all-the-sections-201006.html#p1544515
Inequalities tips: http://gmatclub.com/forum/inequalities-tips-and-hints-175001.html
Debrief, 650 to 750: http://gmatclub.com/forum/650-to-750-a-10-month-journey-to-the-score-203190.html

Manager
Joined: 28 Sep 2013
Posts: 92
GMAT 1: 740 Q51 V39
Followers: 17

Kudos [?]: 17 [0], given: 80

Re: If represents one of the operations +, -, and x, is k(l+m [#permalink]

### Show Tags

08 Jul 2016, 02:31
Bunuel wrote:
If @ represents one of the operations +, -, and x, is k@(l+m)=(k@l)+(k@m) for all numbers k, l,and m?

(1) k@1 is not equal to 1@k for some numbers k. @ is neither addition (as $$k+1=1+k$$) nor multiplication (as $$k*1=1*k$$), thus @ represents subtraction. Knowing that we can determine whether $$k-(l+m)=(k-l)+(k-m)$$ for all numbers k, l,and m. Sufficient.

(2) @ represents subtraction. The same here. Sufficient.

From both statement 1 and statment 2 we will get K=0 that means that this k@(l+m)=(k@l)+(k@m) is not true for all numbers. How come D be the solution it should be E?
_________________

Richa Champion | My GMAT Journey - 470 720 740

Target 760+

Not Improving after Multiple attempts. I can guide You.
Contact me richacrunch2@gmail.com

Math Expert
Joined: 02 Sep 2009
Posts: 38846
Followers: 7719

Kudos [?]: 105942 [0], given: 11602

Re: If represents one of the operations +, -, and x, is k(l+m [#permalink]

### Show Tags

08 Jul 2016, 07:17
crunchboss wrote:
Bunuel wrote:
If @ represents one of the operations +, -, and x, is k@(l+m)=(k@l)+(k@m) for all numbers k, l,and m?

(1) k@1 is not equal to 1@k for some numbers k. @ is neither addition (as $$k+1=1+k$$) nor multiplication (as $$k*1=1*k$$), thus @ represents subtraction. Knowing that we can determine whether $$k-(l+m)=(k-l)+(k-m)$$ for all numbers k, l,and m. Sufficient.

(2) @ represents subtraction. The same here. Sufficient.

From both statement 1 and statment 2 we will get K=0 that means that this k@(l+m)=(k@l)+(k@m) is not true for all numbers. How come D be the solution it should be E?

_________________
Re: If represents one of the operations +, -, and x, is k(l+m   [#permalink] 08 Jul 2016, 07:17
Similar topics Replies Last post
Similar
Topics:
If * represents one of the operations +, -, x, is 3 01 Aug 2011, 07:41
4 If ° represents one of the operations +, –, and ×, 11 19 Jul 2015, 04:19
2 If represents one of the operations +, -, and x, is k(l+m)=(kl)+(k 15 11 May 2016, 16:06
4 If & represents one of the operations +, - and x. Is (a&b) + 7 03 Jul 2014, 05:25
4 If # represents one of the operations +,- and *, is a # 11 28 Sep 2016, 20:59
Display posts from previous: Sort by