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.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 500,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

Is the number of members of Club X greater than the number of members of Club Y ? (1)Of the members of Club X, 20 percent are also members of Club Y. (2)Of the members of Club Y, 30 percent are also members of Club X.

can we use matrix approach for this question. every body is saying: 0.20x=0.30y x/y=3/2 so x>y.

what i know is ratios are not enough to compare two quantities. I am very bad at Ratio and proportions. Please explain

Is the number of members of Club X greater than the number of members of Club Y?

(1) Of the members of Club X, 20 percent are also members of Club Y --> 20% of X are members of both X and Y --> 0.2X={both}. Not sufficient.

(2) Of the members of Club Y, 30 percent are also members of Club X --> 30% of Y are members of both X and Y --> 0.3Y={both}. Not sufficient.

what i know is ratios are not enough to compare two quantities. I am very bad at Ratio and proportions. Please explain

If x and y are both negative then x<y, for example: x=-3<-2=y and if x and y are both positive then x>y. So generally you are right x/y=3/2 is NOT enough to say whether x>y. Though in our case since x and y represent # of people then we know that they must be positive integers, so case 1 is ruled out and we CAN say that x>y.

Re: Is the number of members of Club X greater than the number [#permalink]

Show Tags

08 May 2012, 06:35

1

This post received KUDOS

From what I can deduce, we can make a table for the two possibilities (table formatting is a mess, sorry) :

...................|.Club Y..........NOT Club Y | Club X...........|....? ..............................| X NOT Club X.....|.....................................| .......................Y Let X be the number of members in club X and let Y be the number of members in club Y. Question stem asks whether X>Y?

1. Top left corner contains info about number common number of members in both clubs. Thus, ? = .2 X But we can't decide whether X>Y. NOT SUFFICIENT.

2. Top left corner contains info about number common number of members in both clubs. Thus, ? = .3 Y But we can't decide whether X>Y. NOT SUFFICIENT.

Combine the two, ? = .2X = .3 Y. Since number of members is a positive integer, we know the answer to X>Y. SUFFICIENT.

Re: Is the number of members of Club X greater than the number [#permalink]

Show Tags

14 Aug 2012, 03:41

5

This post received KUDOS

Using the table it can also be solved easily. As the individual entries result in insufficient data, options A/B/D can be eliminated. Combining both the entries we can observe under the column "members of X and members of Y" ,the value of .2X=.3Y, which answers X>Y .Hence C is the ans.

Attachments

tb.jpg [ 18.72 KiB | Viewed 23415 times ]

_________________

Whatever one does in life is a repetition of what one has done several times in one's life! If my post was worth it, then i deserve kudos

Re: Is the number of members of Club X greater than the number [#permalink]

Show Tags

15 Jun 2013, 10:47

6

This post received KUDOS

2

This post was BOOKMARKED

clearly A or B were insufficient.

my process : Total members = Members of X only (Say A) + Members of Y Only (Say B) + Members of Both = A + B + both Now from the statements both= either 0.2A or 0.3B Total = A + B + 0.2A or = A + B + 0.3B Equating both A + B + 0.2A= A + B +0.3B 0.2A=0.3B A=1.5B => X>Y Answer C

Re: Is the number of members of Club X greater than the number [#permalink]

Show Tags

03 Dec 2013, 22:31

nanz236 wrote:

clearly A or B were insufficient.

my process : Total members = Members of X only (Say A) + Members of Y Only (Say B) + Members of Both = A + B + both Now from the statements both= either 0.2A or 0.3B Total = A + B + 0.2A or = A + B + 0.3B Equating both A + B + 0.2A= A + B +0.3B 0.2A=0.3B A=1.5B => X>Y Answer C

yes, i agree with your approach. It was very hard for me to understand how can we equate 0.2x = 0.3y. I do not seem to get the correlation between these 2 statements to equate 0.2Y = 0.3 Y.

Re: Is the number of members of Club X greater than the number [#permalink]

Show Tags

02 Jul 2014, 15:44

2

This post received KUDOS

I got this question wrong because I didn't think to set the x and y statements against each other, because in my mind I just pictured .2x and .3y as different figures. After I reviewed the problem I pictured it this way and it became clear (I'm not using the numbers from the problem):

Group X: Group Y:

So what makes up group x's overlap?

What makes up group y's overlap?

In my example 80% of group X is in group y, and 66.6% of group y is in group b, but the actual count is the exact same for both so you can set them against each other.

Re: Is the number of members of Club X greater than the number [#permalink]

Show Tags

30 Jul 2014, 08:07

Bunuel wrote:

TomB wrote:

Is the number of members of Club X greater than the number of members of Club Y ? (1)Of the members of Club X, 20 percent are also members of Club Y. (2)Of the members of Club Y, 30 percent are also members of Club X.

can we use matrix approach for this question. every body is saying: 0.20x=0.30y x/y=3/2 so x>y.

what i know is ratios are not enough to compare two quantities. I am very bad at Ratio and proportions. Please explain

Is the number of members of Club X greater than the number of members of Club Y?

(1) Of the members of Club X, 20 percent are also members of Club Y --> 20% of X are members of both X and Y --> 0.2X={both}. Not sufficient.

(2) Of the members of Club Y, 30 percent are also members of Club X --> 30% of Y are members of both X and Y --> 0.3Y={both}. Not sufficient.

what i know is ratios are not enough to compare two quantities. I am very bad at Ratio and proportions. Please explain

If x and y are both negative then x<y, for example: x=-3<-2=y and if x and y are both positive then x>y. So generally you are right x/y=3/2 is NOT enough to say whether x>y. Though in our case since x and y represent # of people then we know that they must be positive integers, so case 1 is ruled out and we CAN say that x>y.

Hope it's clear.

Hi Can I solve this kind of question by assuming total numbers?? for example while combining 1 and 2: I assumed 100 total members then assumed two scenarios : 1: X group: 30 members: 20% in Y , 51 in X 2 Y group: 70 : 70+6 = 76 30% IN X

The same way vice versa situation where X is 70 and Y is 30: By doing this way I got E.... cAN you pls explain why my approach is wrong???

Is the number of members of Club X greater than the number of members of Club Y ? (1)Of the members of Club X, 20 percent are also members of Club Y. (2)Of the members of Club Y, 30 percent are also members of Club X.

can we use matrix approach for this question. every body is saying: 0.20x=0.30y x/y=3/2 so x>y.

what i know is ratios are not enough to compare two quantities. I am very bad at Ratio and proportions. Please explain

Is the number of members of Club X greater than the number of members of Club Y?

(1) Of the members of Club X, 20 percent are also members of Club Y --> 20% of X are members of both X and Y --> 0.2X={both}. Not sufficient.

(2) Of the members of Club Y, 30 percent are also members of Club X --> 30% of Y are members of both X and Y --> 0.3Y={both}. Not sufficient.

what i know is ratios are not enough to compare two quantities. I am very bad at Ratio and proportions. Please explain

If x and y are both negative then x<y, for example: x=-3<-2=y and if x and y are both positive then x>y. So generally you are right x/y=3/2 is NOT enough to say whether x>y. Though in our case since x and y represent # of people then we know that they must be positive integers, so case 1 is ruled out and we CAN say that x>y.

Hope it's clear.

Hi Can I solve this kind of question by assuming total numbers?? for example while combining 1 and 2: I assumed 100 total members then assumed two scenarios : 1: X group: 30 members: 20% in Y , 51 in X 2 Y group: 70 : 70+6 = 76 30% IN X

The same way vice versa situation where X is 70 and Y is 30: By doing this way I got E.... cAN you pls explain why my approach is wrong???

Your approach does not make much sense. The statements give certain relationship between the numbers in X and Y, you cannot assume arbitrary values for them.

Also, if there are 30 members in X, then 20% of them, so 6 members, are also in Y. Now, we also know that these 6 members comprise 30% of Y, so 0.3Y=6 --> Y=20 --> X=30 > Y=20.
_________________

Re: Is the number of members of Club X greater than the number [#permalink]

Show Tags

21 Jan 2015, 07:27

This question was frustrating to me. My answer is E because there was no mention of the amount of people in each club for instance: club A has 10 people, club B has 20 people

Overlap= 6B+2A

Club A then has 8 members Club B has 14 members or if the numbers are different then Club A could have more leading to both being insufficient.

Is the assumption that there are both the same number of people in each club to start or is this a flaw??

This question was frustrating to me. My answer is E because there was no mention of the amount of people in each club for instance: club A has 10 people, club B has 20 people

Overlap= 6B+2A

Club A then has 8 members Club B has 14 members or if the numbers are different then Club A could have more leading to both being insufficient.

Is the assumption that there are both the same number of people in each club to start or is this a flaw??

We are asked whether the number of members of Club X is greater than the number of members of Club Y. How can we assume that there are equal number of people in X and Y?

We're asked if the number of members of Club X is greater than the number of members of Club Y? This is a YES/NO question. In these sorts of situations, it's common for some members to belong to BOTH Clubs, so we have to keep careful track of the numbers and possibilities....

Fact 1: 20% of the members of Club X are ALSO members of Club Y

IF... Club X has 100 members, then 20 of those members ALSO belong to Club Y. IF Club Y has 0 unique members, then the answer to the question is YES. IF Club Y as 1,000 unique members, then the answer to the question is NO. Fact 1 is INSUFFICIENT

Fact 2: 30% of the members of Club Y are ALSO members of Club X

This Fact offers the same general logic as Fact 1 (above). Without knowing the number of unique members in Club X, the answer to the question could be either YES or NO. Fact 2 is INSUFFICIENT

Combined, we know... 20% of the members of Club X are ALSO members of Club Y 30% of the members of Club Y are ALSO members of Club X These specific members are the SAME PEOPLE...

This means that .2(X) = .3(Y)

2X = 3Y X = (3/2)(Y)

This means that X MUST be greater than Y, so the answer to the question is ALWAYS YES. Combined, SUFFICIENT

Re: Is the number of members of Club X greater than the number [#permalink]

Show Tags

20 Jul 2015, 23:12

Bunuel wrote:

GGMAT760 wrote:

Bunuel wrote:

Is the number of members of Club X greater than the number of members of Club Y ? Hi Can I solve this kind of question by assuming total numbers?? for example while combining 1 and 2: I assumed 100 total members then assumed two scenarios : 1: X group: 30 members: 20% in Y , 51 in X 2 Y group: 70 : 70+6 = 76 30% IN X

The same way vice versa situation where X is 70 and Y is 30: By doing this way I got E.... cAN you pls explain why my approach is wrong???

Your approach does not make much sense. The statements give certain relationship between the numbers in X and Y, you cannot assume arbitrary values for them.

Also, if there are 30 members in X, then 20% of them, so 6 members, are also in Y. Now, we also know that these 6 members comprise 30% of Y, so 0.3Y=6 --> Y=20 --> X=30 > Y=20.

If I adopt the method of assuming numbers, would this make sense-

Statement 1:

Assume X to have 100 members. therefore, 20% of 100 = 20 20 members of X also belong to Y

Insuff.

Statement 2: Assume Y to have 100 members. 30% of Y= 30 30 members of Y also belong to X

Insuff.

1+2:

We know: 1. 30% of Y belong to X; and 2. 20 members of X belong to Y

Re: Is the number of members of Club X greater than the number [#permalink]

Show Tags

19 Dec 2015, 21:28

1

This post received KUDOS

EMPOWERgmatRichC wrote:

Hi All,

This DS question can be solved by TESTing VALUES.

We're asked if the number of members of Club X is greater than the number of members of Club Y? This is a YES/NO question. In these sorts of situations, it's common for some members to belong to BOTH Clubs, so we have to keep careful track of the numbers and possibilities....

Fact 1: 20% of the members of Club X are ALSO members of Club Y

IF... Club X has 100 members, then 20 of those members ALSO belong to Club Y. IF Club Y has 0 unique members, then the answer to the question is YES. IF Club Y as 1,000 unique members, then the answer to the question is NO. Fact 1 is INSUFFICIENT

Fact 2: 30% of the members of Club Y are ALSO members of Club X

This Fact offers the same general logic as Fact 1 (above). Without knowing the number of unique members in Club X, the answer to the question could be either YES or NO. Fact 2 is INSUFFICIENT

Combined, we know... 20% of the members of Club X are ALSO members of Club Y 30% of the members of Club Y are ALSO members of Club X These specific members are the SAME PEOPLE...

This means that .2(X) = .3(Y)

2X = 3Y X = (3/2)(Y)

This means that X MUST be greater than Y, so the answer to the question is ALWAYS YES. Combined, SUFFICIENT

What if Club X had 100 people, 20 of whom are also in Club Y. But then Club Y had 50 people, 15 of whom are also in Club X.

But then you can reverse those values, and you could say what if Club x had 50 people, 10 of whom are in Club y, and Club y had 100 people, 30 of whom are in Club X.

Why does this above logic not make sense (sets the answer as E)? It must not, as the answer is C.

EDIT: nevermind, I just got it. You can't make up those 2 values as it results in the Club X+Y group having two different values, when they are 1 group. Clearly didn't follow that...I'll leave my thinking and train of thought incase it helps someone else.

The work that you did in your 'example' is actually really USEFUL - once you notice that the two numbers MUST be the same, you have the proof that the values of X and Y ARE related (so the answer must be C). Sometimes the work that you have to do in a DS questions helps you to prove what is NOT possible - and while it might not be the most straight-forward approach, it can still help you to still answer the question correctly.

Re: Is the number of members of Club X greater than the number [#permalink]

Show Tags

17 Feb 2016, 10:50

1

This post received KUDOS

Bunuel wrote:

TomB wrote:

Is the number of members of Club X greater than the number of members of Club Y ? (1)Of the members of Club X, 20 percent are also members of Club Y. (2)Of the members of Club Y, 30 percent are also members of Club X.

can we use matrix approach for this question. every body is saying: 0.20x=0.30y x/y=3/2 so x>y.

what i know is ratios are not enough to compare two quantities. I am very bad at Ratio and proportions. Please explain

Is the number of members of Club X greater than the number of members of Club Y?

(1) Of the members of Club X, 20 percent are also members of Club Y --> 20% of X are members of both X and Y --> 0.2X={both}. Not sufficient.

(2) Of the members of Club Y, 30 percent are also members of Club X --> 30% of Y are members of both X and Y --> 0.3Y={both}. Not sufficient.

what i know is ratios are not enough to compare two quantities. I am very bad at Ratio and proportions. Please explain

If x and y are both negative then x<y, for example: x=-3<-2=y and if x and y are both positive then x>y. So generally you are right x/y=3/2 is NOT enough to say whether x>y. Though in our case since x and y represent # of people then we know that they must be positive integers, so case 1 is ruled out and we CAN say that x>y.

Hope it's clear.

Dear, Bunuel! Please tell me whether my reasoning is correct? Thanks

Attachments

yyyyyyyyyyyyyyyyyy.JPG [ 23.82 KiB | Viewed 12755 times ]

Re: Is the number of members of Club X greater than the number [#permalink]

Show Tags

04 Nov 2016, 08:53

TomB wrote:

Is the number of members of Club X greater than the number of members of Club Y ?

(1) Of the members of Club X, 20 percent are also members of Club Y. (2) Of the members of Club Y, 30 percent are also members of Club X.

can we use matrix approach for this question. every body is saying: 0.20x=0.30y x/y=3/2 so x>y.

what i know is ratios are not enough to compare two quantities. I am very bad at Ratio and proportions. Please explain

Make a Venn Diagram. Statement one states that 20% of X are also in Y. Insufficient. Statement two states that 30% of Y are also in X. Insufficient.

When you combine them you can see from drawing a venn diagram that the number of people in both groups have to be the same. Since 20% of X has to equal 30% of Y, you can set Y to 100. 30% of 100 is 30 so that will be the both section. Since 30 has to equal 20% of X, just multiple 5 x 30. 150 is X 100 is y and 30 is both. X bigger.

Re: Is the number of members of Club X greater than the number [#permalink]

Show Tags

29 May 2017, 10:15

studentsensual wrote:

Bunuel wrote:

TomB wrote:

Is the number of members of Club X greater than the number of members of Club Y ? (1)Of the members of Club X, 20 percent are also members of Club Y. (2)Of the members of Club Y, 30 percent are also members of Club X.

can we use matrix approach for this question. every body is saying: 0.20x=0.30y x/y=3/2 so x>y.

what i know is ratios are not enough to compare two quantities. I am very bad at Ratio and proportions. Please explain

Is the number of members of Club X greater than the number of members of Club Y?

(1) Of the members of Club X, 20 percent are also members of Club Y --> 20% of X are members of both X and Y --> 0.2X={both}. Not sufficient.

(2) Of the members of Club Y, 30 percent are also members of Club X --> 30% of Y are members of both X and Y --> 0.3Y={both}. Not sufficient.

what i know is ratios are not enough to compare two quantities. I am very bad at Ratio and proportions. Please explain

If x and y are both negative then x<y, for example: x=-3<-2=y and if x and y are both positive then x>y. So generally you are right x/y=3/2 is NOT enough to say whether x>y. Though in our case since x and y represent # of people then we know that they must be positive integers, so case 1 is ruled out and we CAN say that x>y.

Hope it's clear.

Dear, Bunuel! Please tell me whether my reasoning is correct? Thanks

used the same approach but not sure whether this is correct

I guess if we also take into account that 20% of X = 30 % of Y than your reasoning is correct

but without this information we don't know whether 80% of X > 70% of Y (at least in my opinion)
_________________

Re: Is the number of members of Club X greater than the number [#permalink]

Show Tags

17 Aug 2017, 19:52

sukeshap wrote:

TomB wrote:

Is the number of members of Club X greater than the number of members of Club Y ?

(1) Of the members of Club X, 20 percent are also members of Club Y. (2) Of the members of Club Y, 30 percent are also members of Club X.

Take an example, Both club are having 1000 members, 200 of club X is having membership in Y- Insufficient 300 of club Y is having membership in X- Insufficient Both together is not giving any conclusion, so the answer is E.

Please correct me if I am wrong

If both clubs have 1000 members, x overlap=200,y overlap=300. Since x overlap=y overlap, so x if overlap is increased, then x starts becoming greater than 1000 or if y overlap is reduced then y starts becoming less than 1000. Either way x>y.