It is currently 17 Oct 2017, 01:06

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

PS: Boy & Girl. 600-700 Ranking

  post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
Senior Manager
Senior Manager
User avatar
Joined: 07 Jan 2008
Posts: 398

Kudos [?]: 289 [0], given: 0

PS: Boy & Girl. 600-700 Ranking [#permalink]

Show Tags

New post 29 Aug 2008, 00:10
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

Image

The given information seems to be excessive. We do not need all constrains to solve problem.

Kudos [?]: 289 [0], given: 0

Director
Director
User avatar
Joined: 03 Sep 2006
Posts: 866

Kudos [?]: 1066 [0], given: 33

GMAT ToolKit User
Re: PS: Boy & Girl. 600-700 Ranking [#permalink]

Show Tags

New post 29 Aug 2008, 01:09
Ba/Ga = 3/4

Bb/Gb = 4/5

(Ba+Bb)/(Ga+Gb) = 17/22

(3Ga-2)/(Ga-1) = 34/11

Ga = 12

What was excessive and what is your approach?

Kudos [?]: 1066 [0], given: 33

Current Student
User avatar
Joined: 11 May 2008
Posts: 555

Kudos [?]: 220 [0], given: 0

Re: PS: Boy & Girl. 600-700 Ranking [#permalink]

Show Tags

New post 29 Aug 2008, 01:29
i think that this is where diff thinking can make a diff on the GMAT...
B:G ratio is 17:22.
this means what????
b=17x
G=22x or girls = 22,44,66,88 etc...

and Ga = Gb+2 (Ga - girls in A)
or Gb=Ga-2

from the ans choices. select that no. for girls in A, and so the girls in B will be 2 less than that. when these two are added they should be a multipe of 22.
only 12 satisfies this ...
so ans =E
time taken= 1min 50 sec..
(BUT IS THE ANS RIGHT???)

Kudos [?]: 220 [0], given: 0

Senior Manager
Senior Manager
User avatar
Joined: 07 Jan 2008
Posts: 398

Kudos [?]: 289 [0], given: 0

Re: PS: Boy & Girl. 600-700 Ranking [#permalink]

Show Tags

New post 29 Aug 2008, 08:20
LM wrote:
Ba/Ga = 3/4

Bb/Gb = 4/5

(Ba+Bb)/(Ga+Gb) = 17/22

(3Ga-2)/(Ga-1) = 34/11

Ga = 12

What was excessive and what is your approach?


We do not need the information shows 17/22 ratio.
I got 12 as well.

Kudos [?]: 289 [0], given: 0

Director
Director
User avatar
Joined: 12 Jul 2008
Posts: 514

Kudos [?]: 162 [0], given: 0

Schools: Wharton
Re: PS: Boy & Girl. 600-700 Ranking [#permalink]

Show Tags

New post 29 Aug 2008, 08:25
lexis wrote:
Image

The given information seems to be excessive. We do not need all constrains to solve problem.


Ba/Ga = 3/4
Bb/Gb = 4/5
(Ba + Bb)/(Ga + Gb) = 17/22

Bb = Ba - 1
Gb = Ga - 2

(2Ba - 1)/(2Ga - 2) = 17/22
Ba = (3/4)Ga

(2*(3/4)*Ga - 1)/(2Ga - 2) = 17/22
22*2*(3/4)*Ga - 22 = 17*2*Ga -34
33Ga - 22 = 34Ga - 34
Ga = 12

Kudos [?]: 162 [0], given: 0

Manager
Manager
avatar
Joined: 28 Aug 2008
Posts: 101

Kudos [?]: 43 [0], given: 0

Re: PS: Boy & Girl. 600-700 Ranking [#permalink]

Show Tags

New post 31 Aug 2008, 09:25
E... Agreed

I solved by back-solving, just plug in values to meet the conditions from the stem, 12 is the obvious choice.


If 12 girls in A then 9 boys in A

If 9 boys in A then 8 boys in B

If 12 girls in A then 10 girls in B

9+8=17
12+10=22

ratio =17/22

Time take - 45 seconds (varies based on which answer you select to back-solve, some might initially select a wrong answer, but is should be easy to tell at an early stage that its wrong)

Kudos [?]: 43 [0], given: 0

Expert Post
GMAT Tutor
avatar
B
Joined: 24 Jun 2008
Posts: 1339

Kudos [?]: 1951 [0], given: 6

Re: PS: Boy & Girl. 600-700 Ranking [#permalink]

Show Tags

New post 31 Aug 2008, 18:57
The information has one excessive fact anyway, but with those answer choices, the problem is absolutely straightforward:

We're told that class B has two fewer girls than class A. From the answer choices, class B must have 6, 7, 8, 9 or 10 girls. In class B, the ratio of boys to girls is 4 to 5. This guarantees that the number of girls in class B is divisible by 5. So the answer must be E, 12, because only 12-2 = 10 gives a multiple of 5.

So with those answer choices, the rest of the information in the question is completely unnecessary. E. What's the source?
_________________

GMAT Tutor in Toronto

If you are looking for online GMAT math tutoring, or if you are interested in buying my advanced Quant books and problem sets, please contact me at ianstewartgmat at gmail.com

Kudos [?]: 1951 [0], given: 6

Re: PS: Boy & Girl. 600-700 Ranking   [#permalink] 31 Aug 2008, 18:57
Display posts from previous: Sort by

PS: Boy & Girl. 600-700 Ranking

  post reply Question banks Downloads My Bookmarks Reviews Important topics  


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®.