It is currently 21 Apr 2018, 14:05

Close

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Of the birds in a particular aviary, 30 are both spotted and

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

Hide Tags

Intern
Intern
avatar
Status: Hulk
Joined: 17 Jul 2013
Posts: 11
Location: Singapore
Concentration: Entrepreneurship, Finance
Schools: Insead '14 (M)
GMAT 1: 600 Q44 V30
GMAT 2: 650 Q45 V34
GMAT 3: 690 Q49 V34
Of the birds in a particular aviary, 30 are both spotted and [#permalink]

Show Tags

New post Updated on: 11 Dec 2013, 03:47
2
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  35% (medium)

Question Stats:

68% (00:59) correct 32% (00:41) wrong based on 345 sessions

HideShow timer Statistics

Of the birds in a particular aviary, 30 are both spotted and crested and 10 are neither spotted nor crested. What is the total number of birds in the aviary?

(1) The number of birds that are spotted but not crested is 10 greater than the number of birds that are crested but not spotted.

(2) More than 3/5 of the birds in the aviary are spotted.
[Reveal] Spoiler: OA

Originally posted by xhimi on 10 Dec 2013, 19:48.
Last edited by xhimi on 11 Dec 2013, 03:47, edited 1 time in total.
Expert Post
3 KUDOS received
Veritas Prep GMAT Instructor
User avatar
P
Joined: 16 Oct 2010
Posts: 8028
Location: Pune, India
Re: Of the birds in a particular aviary, 30 are both spotted and [#permalink]

Show Tags

New post 11 Dec 2013, 00:03
3
This post received
KUDOS
Expert's post
xhimi wrote:
Of the birds in a particular aviary, 30 are both spotted and crested and 10 are neither spotted nor crested. What is the total number of birds in the aviary?

(1) The number of birds that are spotted but not crested is 10 greater than the number of birds that are crested but not spotted.

(2) More than 3/5 of the birds in the aviary are spotted.


Draw the venn diagram. You know this from the question stem:

Attachment:
Ques3.jpg
Ques3.jpg [ 15.47 KiB | Viewed 6267 times ]


We need to find the following Total Sum: 10 + pink region + 30 + yellow region

(1) The number of birds that are spotted but not crested is 10 greater than the number of birds that are crested but not spotted.
This says that the pink region is 10 more than the yellow region. But we have no numerical value for the pink and yellow regions.

(2) More than 3/5 of the birds in the aviary are spotted.
This says (pink region + 30) > (3/5) Total Sum
Again, we have no values for pink and yellow regions. This inequality will hold for many values of pink region and yellow region.

Taking both together, say yellow region = x, pink region = 10+x
(10 + x + 30) > (3/5)*(10 + 10 + x + 30 + x)
x < 50

Still x can take many values. For example: x = 40
Spotted birds = 70
Total birds = 110
7/11 > 3/5

x = 30
Spotted birds = 60
Total birds = 90
60/90 > 3/5

Total number of birds will be different in each case.

Answer (E)
_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Get started with Veritas Prep GMAT On Demand for $199

Veritas Prep Reviews

Senior Manager
Senior Manager
avatar
G
Joined: 26 Dec 2015
Posts: 280
Location: United States (CA)
Concentration: Finance, Strategy
WE: Investment Banking (Venture Capital)
Re: Of the birds in a particular aviary, 30 are both spotted and [#permalink]

Show Tags

New post 08 Oct 2017, 11:47
Of the birds in a particular aviary, 30 are both spotted and crested and 10 are neither spotted nor crested. What is the total number of birds in the aviary?

(1) The number of birds that are spotted but not crested is 10 greater than the number of birds that are crested but not spotted.

(2) More than 3/5 of the birds in the aviary are spotted.

At the very least, you can use POE to elim some A/C to give yourself a fighting chance if you're low on time/not fond of these types of problems.

Q: WHAT IS THE TOTAL (ABSOLUTE) # OF BIRDS?

1) gives us a RELATIONSHIP, not an ABSOLUTE #.
> ELIM AD

2) same as "1"
> ELIM B

Now, you're duking it out between C & E. All within a matter of what, like 30 seconds?

3) when you combine the two, understand that since you're given a range of #s, you can get multiple answers...hence, C is out.
> Ans: E
Re: Of the birds in a particular aviary, 30 are both spotted and   [#permalink] 08 Oct 2017, 11:47
Display posts from previous: Sort by

Of the birds in a particular aviary, 30 are both spotted and

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


cron

GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

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®.