Set and subset

Expert replies

Mormuse: Junior | Next Rank: 30 Posts; Posts: 24; Joined: Thu Mar 07, 2013 5:30 am

by Mormuse » Fri Mar 29, 2013 4:36 am

If the mean of set S does not exceed mean of any subset of S, which of the following must be true about S?...
1) S contains only one element
2) all elements of set S are equal
3) median of set S equals the mean of set S

Answer choice: Classic roman numeral choices.
I don't get why 1 is not possible? I answered 1,2 and 3 but the answer is 2 and 3. Help anyone?
Thanks!!!

Like this post

Source: Beat The GMAT — Problem Solving | Fri Mar 29, 2013 4:36 am

GMATGuruNY: GMAT Instructor; Posts: 15539; Joined: Tue May 25, 2010 12:04 pmFollowed by: 1906 members; Location: New York, NY; Thanked: 13060 times; GMAT Score:790

by GMATGuruNY » Fri Mar 29, 2013 7:32 am

claudayst wrote:If the mean of set S does not exceed mean of any subset of S, which of the following must be true about S?...

I: S contains only one element

I don't get why 1 is not possible?

The question stems asks not whether statement I is POSSIBLE but whether statement 1 MUST BE TRUE.
The constraint in the question stem -- that the mean of set S does not exceed the mean of any subset of S -- is satisfied by the following case:
S = {1,1}.
Thus, it does not have to true that S contains only one element.

Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3

Like this post

Mormuse: Junior | Next Rank: 30 Posts; Posts: 24; Joined: Thu Mar 07, 2013 5:30 am

by Mormuse » Fri Mar 29, 2013 7:49 am

Seems like i fell upright in the trap!! Thx!

Like this post

Jim@StratusPrep: MBA Admissions Consultant; Posts: 2279; Joined: Fri Nov 11, 2011 7:51 amFollowed by: 266 members; Location: New York; Thanked: 660 times; GMAT Score:770

by Jim@StratusPrep » Fri Mar 29, 2013 7:52 am

One element would mean only one 2 ------ {2}

However, you can have more than one ------- {2, 2, 2, 2}

GMAT Answers provides a world class adaptive learning platform.
-- Push button course navigation to simplify planning
-- Daily assignments to fit your exam timeline
-- Organized review that is tailored based on your abiility
-- 1,000s of unique GMAT questions
-- 100s of handwritten 'digital flip books' for OG questions
-- 100% Free Trial and less than $20 per month after.
-- Free GMAT Quantitative Review

Like this post

Post new topic Post Reply

• Page 1 of 1

GMAT Course Reviews

559 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