Tricky Math Question - Error in Question (pls do not refer) : GMAT Problem Solving (PS)
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 17 Jan 2017, 21:29

### 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
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

# Events & Promotions

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

# Tricky Math Question - Error in Question (pls do not refer)

 post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:

### Hide Tags

Intern
Joined: 09 Sep 2010
Posts: 12
Followers: 0

Kudos [?]: 8 [0], given: 11

Tricky Math Question - Error in Question (pls do not refer) [#permalink]

### Show Tags

13 Feb 2011, 00:48
00:00

Difficulty:

(N/A)

Question Stats:

20% (02:26) correct 80% (00:26) wrong based on 5 sessions

### HideShow timer Statistics

Q- In the junior basketball league there are 18 teams, 2/3 of them are bad and 1/2 are rich. What can't be the number of teams that are rich and bad?
a)4 b)6 c) 10 d)13 e)15

The Answer is (C)

The given explanation is :
12 teams are bad and 9 are rich.
The no. of teams which are rich and that are bad must be between 9 and (9+12-18=3)

The only answer, which is not in that range is (C)

I did not understand this explanation. Please help me !! Thanks in advance.
[Reveal] Spoiler: OA

Last edited by sandhyash on 13 Feb 2011, 06:39, edited 1 time in total.
Manager
Joined: 20 Dec 2010
Posts: 168
Location: Stockholm, Sweden
Followers: 2

Kudos [?]: 50 [0], given: 5

Re: Tricky Math Question [#permalink]

### Show Tags

13 Feb 2011, 02:32
They can be both bad and rich.

Think of it as a Venn-diagram, left circle bad and right circle rich.

If 10 are both bad and rich, that implies that at least 10 are bad, but only 9 are bad so it cannot be true.
_________________

12/2010 GMATPrep 1 620 (Q34/V41)
01/2011 GMATPrep 2 640 (Q42/V36)
01/2011 GMATPrep 3 700 (Q47/V39)
02/2011 GMATPrep 4 710 (Q48/V39)
02/2011 MGMAT CAT 1 650 (Q46/V32)
02/2011 MGMAT CAT 2 680 (Q46/V36)
02/2011 MGMAT CAT 3 710 (Q45/V41)

Math Expert
Joined: 02 Sep 2009
Posts: 36540
Followers: 7073

Kudos [?]: 93050 [0], given: 10541

Re: Tricky Math Question [#permalink]

### Show Tags

13 Feb 2011, 02:58
Moved to PS subforum.

sandhyash wrote:
Q- In the junior basketball league there are 18 teams, 2/3 of them are bad and 1/2 are rich. What can't be the number of teams that are rich and bad?

a) 4
b) 6
c) 10
d) 13
e) 15

The Answer is (C)

The given explanation is :
12 teams are bad and 9 are rich.
The no. of teams which are rich and that are bad must be between 9 and (9+12-18=3)

The only answer, which is not in that range is (C)

I did not understand this explanation. Please help me !! Thanks in advance.

How can the number of teams that are BOTH rich and bad be more than the teams that are rich (9)? So 9 is the upper limit for the number of teams that are BOTH rich and bad. The lower limit for the the number of teams that are BOTH rich and bad is 3: TOTAL=Bad+Rich-Both+Neither --> 18=12+9-Both+Neither --> Both=3+Neither, so if there are no teams that are neither bad or rich then Both=3.

So there are 3 values among answer choices which can't be the number of teams that are both rich and bad: C, D, and E.

P.S.
 ! Please post PS questions in the PS subforum: gmat-problem-solving-ps-140/Please post DS questions in the DS subforum: gmat-data-sufficiency-ds-141/No posting of PS/DS questions is allowed in the main Math forum.

_________________
Intern
Joined: 06 Feb 2011
Posts: 29
Followers: 0

Kudos [?]: 5 [0], given: 4

Re: Tricky Math Question [#permalink]

### Show Tags

13 Feb 2011, 05:16
Yes! C,D& E all can't be both bad and rich. And yet the OA states that only C is correct. How is this so?
Intern
Joined: 09 Sep 2010
Posts: 12
Followers: 0

Kudos [?]: 8 [0], given: 11

Re: Tricky Math Question [#permalink]

### Show Tags

13 Feb 2011, 06:37
thanks for your prompt response. Sorry for posting my question here, I did not know where to post my query on the website.

As for the solution, even this was not making sense to me. I was practising from a coaching class material from an academy. I had a feeling that there must be an error in question but I did not want to be over confident either. I dont wish to confuse more people with this question hence I am deleting this thread.
Senior Manager
Joined: 21 Mar 2010
Posts: 314
Followers: 5

Kudos [?]: 30 [0], given: 33

Re: Tricky Math Question - Error in Question (pls do not refer) [#permalink]

### Show Tags

14 Feb 2011, 11:31
sandhyash wrote:
Q- In the junior basketball league there are 18 teams, 2/3 of them are bad and 1/2 are rich. What can't be the number of teams that are rich and bad?
a)4 b)6 c) 10 d)13 e)15

The Answer is (C)

The given explanation is :
12 teams are bad and 9 are rich.
The no. of teams which are rich and that are bad must be between 9 and (9+12-18=3)

The only answer, which is not in that range is (C)

I did not understand this explanation. Please help me !! Thanks in advance.

I Used the manhattan gmat technique for word translation problems for such questions. make a table of rich/not rich /total along columns and

Bad/not bad/total along rows. Is there an easier way to solve these- provided the answer was right?
Re: Tricky Math Question - Error in Question (pls do not refer)   [#permalink] 14 Feb 2011, 11:31
Similar topics Replies Last post
Similar
Topics:
2 tricky PS question 3 30 Oct 2011, 23:26
Probability Stat question...tricky 3 12 Aug 2011, 10:29
Tricky Question.. Attention required! 1 19 Jun 2011, 22:29
Gmatprep Question, Powers...tricky! 5 07 May 2011, 13:33
2 Tricky Exponents Question 6 13 Apr 2011, 12:23
Display posts from previous: Sort by

# Tricky Math Question - Error in Question (pls do not refer)

 post reply Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group and phpBB SEO Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.