Club X and Club Y

Expert replies

zagcollins: Master | Next Rank: 500 Posts; Posts: 167; Joined: Wed Jun 11, 2008 10:58 pmFollowed by: 1 member; Thanked: 2 times

by zagcollins » Mon Jul 21, 2008 8:05 am

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.

Like this post

Source: Beat The GMAT — Data Sufficiency | Mon Jul 21, 2008 8:05 am

cubicle_bound_misfit: Master | Next Rank: 500 Posts; Posts: 246; Joined: Mon May 19, 2008 7:34 am; Location: Texaco Gas Station; Thanked: 7 times

by cubicle_bound_misfit » Mon Jul 21, 2008 9:07 am

IMO it is C.

using set theory we get

X/5 = 3/10 Y

hence X = 15/10 Y

as X,Y >0 and belongs to Integer.

let me know OA please.

regards,

Cubicle Bound Misfit

Like this post

Canman: Senior | Next Rank: 100 Posts; Posts: 58; Joined: Fri Jul 11, 2008 5:00 am; Thanked: 4 times

by Canman » Mon Jul 21, 2008 9:17 am

Can you walk me through the set theory in a little more detail?

When I run through the problem quickly picking a few numbers and drawing some venn diagrams, I can come up with multiple scenarios where either X is greater, less than or equal to Y that will still satisfy the overlap restrictions of the two statements together.

Thanks!

Like this post

zagcollins: Master | Next Rank: 500 Posts; Posts: 167; Joined: Wed Jun 11, 2008 10:58 pmFollowed by: 1 member; Thanked: 2 times

by zagcollins » Mon Jul 21, 2008 10:11 am

OA is C...Cubicle bound misfit, can you walk me through the problem in a more simplistic manner? i didnt understand the set theory at all...

Like this post

reachac: Legendary Member; Posts: 572; Joined: Fri Feb 22, 2008 9:25 am; Thanked: 21 times

by reachac » Mon Jul 21, 2008 10:43 am

It can be simplified by taking
20% ox X = 30%of Y

Hence X > Y

Like this post

pepeprepa: Legendary Member; Posts: 661; Joined: Tue Jul 08, 2008 12:58 pm; Location: France; Thanked: 48 times

by pepeprepa » Mon Jul 21, 2008 1:17 pm

With the two sentences,
There are people who are in X, people who are in Y and people who are in X and Y.
The number of people who are in X and who also are in Y is the same number as the one of Y who are alos in X.
But we see that this proportion of people who are in both is different between X and Y.
It represents much more for Y than for X so Y is smaller than X.

Example:
150 persons in X
90 persons in Y
30 persons represents only 30/150=20% of X but 30 persons represents 30/90=33,3% of Y

Like this post

Post new topic Post Reply

• Page 1 of 1

GMAT Course Reviews

560 reviews

1168 reviews

431 reviews

359 reviews

147 reviews

5/5

5 Star (560 Reviews)

"Target Test Prep is the closest to the official version of the GMAT exam, about 99% accuracy in terms of the quality and quantity of information. The course has excellently created singular sets of focused lessons and tests for every possible topic that one could come across in the official GMAT exam."

"The TTP course maximizes the efficiency of the time you spend studying. It will take time and effort but I could almost guarantee that if you complete the course exactly as it is laid out you will get an amazing score. They also have a very responsive team willing to help with any questions you might have."

"TTP has two things that I think no other test prep company offers: A teaching approach that reinforces understanding and an attitude that will give you the mental preparedness needed to succeed on the test. TTP gives you a deep understanding of the concept you need to know while teaching you how to think."

Write a Review