Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 07 Jul 2015, 18:55

### 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 the operation # is one of the four arithmetic operations

Author Message
TAGS:
Intern
Joined: 12 Sep 2010
Posts: 10
Followers: 0

Kudos [?]: 15 [2] , given: 0

If the operation # is one of the four arithmetic operations [#permalink]  18 Sep 2010, 19:57
2
KUDOS
3
This post was
BOOKMARKED
00:00

Difficulty:

55% (hard)

Question Stats:

53% (01:47) correct 47% (00:49) wrong based on 329 sessions
If the operation # is one of the four arithmetic operations addition, subtraction, multiplication and division, is (6#2)#4 = 6#(2#4)

(1) 3#2 > 3

(2) 3#1 = 3

Attachment:

DS3.PNG [ 7.48 KiB | Viewed 7172 times ]
[Reveal] Spoiler: OA
Math Expert
Joined: 02 Sep 2009
Posts: 28352
Followers: 4487

Kudos [?]: 45487 [3] , given: 6762

Re: DS question [#permalink]  18 Sep 2010, 20:01
3
KUDOS
Expert's post
If the operation # is one of the four arithmetic operations: addition, subtraction, multiplication and division. Is (6#2)#4 = 6#(2#4) ?

(1) 3#2 > 3. # can be either multiplication or addition. In BOTH cases (6#2)#4 = 6#(2#4) is true: (6*2)*4=6*(2*4)=48 and (6+2)+4=6+(2+4)=12. Sufficient.

(2) 3#1 = 3. # can be either multiplication or division. If it's division the the answer to the question is No and if it's multiplication answer to the question is YES. Two different answers. Not sufficient.

_________________
Intern
Joined: 12 Sep 2010
Posts: 10
Followers: 0

Kudos [?]: 15 [0], given: 0

Re: DS question [#permalink]  18 Sep 2010, 20:10
Bunuel wrote:
If the operation # is one of the four arithmetic operations- addition, subtraction, multiplication and division. Is (6#2)#4= 6#(2#4)

(1) 3#2 > 3, # can be either multiplication or addition in BOTH cases (6#2)#4 = 6#(2#4) is true: (6*2)*4=6*(2*4)=48 and (6+2)+4=6+(2+4)=12. Sufficient.

(2) 3#1 = 3, # can be either multiplication or division. If it's division the the answer to the question is No and if it's multiplication answer to the question is YES. Two different answers. Not sufficient.

Oh!! Anyways thanks Bunuel..I just saw two operations and so felt like i cant solve !!Now I gt it..
Manager
Joined: 23 Sep 2009
Posts: 152
Followers: 1

Kudos [?]: 31 [0], given: 37

Re: DS question [#permalink]  19 Sep 2010, 16:56
Same explanation like Bunnel. Dnt worry I used to make more silly mistakes than what you have done now...And it is all these silly mistakes that afect our score in a huge way....So just relax and solve the problems.....
I am understanding that Panic=failure during exams
_________________

Thanks,
VP

Manager
Joined: 06 Aug 2010
Posts: 225
Location: Boston
Followers: 2

Kudos [?]: 103 [1] , given: 5

Re: DS question [#permalink]  21 Sep 2010, 10:12
1
KUDOS
ravitejapandiri wrote:
Attachment:
DS3.PNG
Please explain me this one..I get Answer C because Fact 1 itself is not sufficient to solve the problem.

F1:Gives * OR +
F2:Gives * OR %

So both give * as the appropriate sign.Hence C

You're given that the operation satisfies the associate property. The associative property is true of addition [(6+2) + 4 = 6 + (2+4)] and multiplication [(6*2) * 4 = 6 * (2*4)], but not of subtraction or division. If we can determine whether the operation is multiplication or addition, or if it's subtraction or division, then we have enough information.

(1) A quick test of each operation will show you that the triangle is either multiplication or addition. Regardless of which one it is, we know that it will satisfy the associative property. Sufficient.

(2) Again, a quick test will show you that the triangle is either multiplication or division. Since multiplication satisfies the property, but division does not, we can't determine the answer. Insufficient.

(A)
Math Expert
Joined: 02 Sep 2009
Posts: 28352
Followers: 4487

Kudos [?]: 45487 [0], given: 6762

Re: If the operation # is one of the four arithmetic operations [#permalink]  21 Jun 2013, 01:48
Expert's post
Bumping for review and further discussion*. Get a kudos point for an alternative solution!

*New project from GMAT Club!!! Check HERE

All DS Functions and Custom Characters questions: search.php?search_id=tag&tag_id=40
All PS Functions and Custom Characters questions: search.php?search_id=tag&tag_id=61

_________________
Intern
Joined: 22 May 2013
Posts: 49
Concentration: General Management, Technology
GPA: 3.9
WE: Information Technology (Computer Software)
Followers: 0

Kudos [?]: 11 [2] , given: 10

Re: If the operation # is one of the four arithmetic operations [#permalink]  22 Jun 2013, 02:20
2
KUDOS
ravitejapandiri wrote:
If the operation # is one of the four arithmetic operations addition, subtraction, multiplication and division, is (6#2)#4 = 6#(2#4)

(1) 3#2 > 3

(2) 3#1 = 3

Attachment:
DS3.PNG

We basically need to answer either a YES or a NO for the equation (6#2)#4 = 6#(2#4)
And if we see the equation, then we know for sure that we can answer the question if # is :-

+ or * =>YES, Equation will hold => Sufficient
- or / => NO Equation will not hold => Sufficient

Now, looking at stetements:

(1) 3#2 > 3
# can either be + or * to hold true, which is one of our conditions as listed above, hence Sufficient
(2) 3#1 = 3
# can be either * or /, hence in this case we cannot be sure as it consists of one possibility from each condition that we had laid out earlier, and thus will result in a YES for * and a NO for /.

Thus (2) is not sufficient as we cannot come up with a definite answer.

Hence, A
_________________

Intern
Joined: 22 Jan 2014
Posts: 1
Followers: 0

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

Re: If the operation # is one of the four arithmetic operations [#permalink]  28 Jan 2014, 00:31
At the risk of sounding stupid, the GMAT Quant thus far has taught me to consider all possible conditions when solving a DS problem and choose only that answer which holds true universally in all cases. Hence my question in this case is:

(1) says the operation can either be Addition (+) or Multiplication (X)

The question asks if LHS = RHS using the above operations in place of the symbol
My observation :
(a) if you use multipication in place of the symbol then LHS = RHS
(b) if you use addition in place of the symbol then LHS = RHS
(c) But if you use a combination of multiplication and addition in the equation then LHS not equal to RHS.

Shouldn't the above (C) be a possibility too, since all we know from (1) is that it can be any operation (+ or X). No where is it specified that the same operation is to be performed on both sides of the equation

Similarly,

(2) says the operation can either be Multiplication (X) or Division (/)

Just as in the above reasoning, if you use a combination, then LHS not equal to RHS

THus using (1) and (2) together, only Multiplication holds good to satisfy both conditions

Therefore shouldn't the answer be (C).

Sorry if this is a stupid question.

Math Expert
Joined: 02 Sep 2009
Posts: 28352
Followers: 4487

Kudos [?]: 45487 [0], given: 6762

Re: If the operation # is one of the four arithmetic operations [#permalink]  28 Jan 2014, 00:37
Expert's post
sriniash wrote:
At the risk of sounding stupid, the GMAT Quant thus far has taught me to consider all possible conditions when solving a DS problem and choose only that answer which holds true universally in all cases. Hence my question in this case is:

(1) says the operation can either be Addition (+) or Multiplication (X)

The question asks if LHS = RHS using the above operations in place of the symbol
My observation :
(a) if you use multipication in place of the symbol then LHS = RHS
(b) if you use addition in place of the symbol then LHS = RHS
(c) But if you use a combination of multiplication and addition in the equation then LHS not equal to RHS.

Shouldn't the above (C) be a possibility too, since all we know from (1) is that it can be any operation (+ or X). No where is it specified that the same operation is to be performed on both sides of the equation

Similarly,

(2) says the operation can either be Multiplication (X) or Division (/)

Just as in the above reasoning, if you use a combination, then LHS not equal to RHS

THus using (1) and (2) together, only Multiplication holds good to satisfy both conditions

Therefore shouldn't the answer be (C).

Sorry if this is a stupid question.

If the operation # is ONE of the four arithmetic operations: addition, subtraction, multiplication and division. Is (6#2)#4 = 6#(2#4) ?

The above means that # in the expression, (6#2)#4 = 6#(2#4), is addition OR subtraction OR multiplication OR division.

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
if-represents-one-of-the-operations-and-x-is-k-l-m-144138.html
if-the-symbol-represents-one-of-the-following-operations-161138.html
the-symbol-represents-one-of-the-following-operations-161432.html

Hope it helps.
_________________
Manager
Joined: 10 May 2014
Posts: 98
Followers: 0

Kudos [?]: 26 [0], given: 18

Re: If the operation # is one of the four arithmetic operations [#permalink]  08 Jan 2015, 09:57
Nice way to test the Assocative Law!

We learn this in primary school, but we see custom characters in the GMAT and tend to freak out...
_________________

Consider giving me Kudos if I helped, but don´t take them away if I didn´t!

What would you do if you weren´t afraid?

Re: If the operation # is one of the four arithmetic operations   [#permalink] 08 Jan 2015, 09:57
Similar topics Replies Last post
Similar
Topics:
1 If the operation # is one of the four arithmetic operations 4 10 May 2010, 08:32
6 If the operation # is one of the four arithmetic operations 3 21 Feb 2010, 10:33
3 If the operation # is one of the four arithmetic operations 10 30 Sep 2007, 11:01
If the operation & is one of the four arithmetic 3 20 Nov 2006, 22:44
If @ denotes one of the four arithmetic operations: 6 10 Sep 2006, 04:19
Display posts from previous: Sort by