Find all School-related info fast with the new School-Specific MBA Forum

It is currently 29 Aug 2014, 02:44

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.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Each of the balls in a jar is either red, green or blue. If

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Manager
Manager
avatar
Joined: 10 Sep 2012
Posts: 151
Followers: 2

Kudos [?]: 33 [0], given: 17

Each of the balls in a jar is either red, green or blue. If [#permalink] New post 30 Nov 2012, 19:21
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

83% (01:42) correct 17% (00:31) wrong based on 66 sessions
Each of the balls in a jar is either red, green or blue. If one ball is removed at random, what is the probability that the ball will be green?

(1) There are 7 blue balls in the jar.
(2) The probability that the ball will be red is 1/4

[Reveal] Spoiler:
I thought this was C because I thought having number of blue balls would close the unknown down to exact numbers. Where am I mistaken? Is there a way to think through this in an elegant manner?
[Reveal] Spoiler: OA
Expert Post
1 KUDOS received
Verbal Forum Moderator
Verbal Forum Moderator
User avatar
Status: Preparing for the another shot...!
Joined: 03 Feb 2011
Posts: 1425
Location: India
Concentration: Finance, Marketing
GPA: 3.75
Followers: 127

Kudos [?]: 598 [1] , given: 62

GMAT ToolKit User GMAT Tests User Premium Member
Re: Each of the balls in a jar is either red, green or blue. If [#permalink] New post 30 Nov 2012, 19:35
1
This post received
KUDOS
Expert's post
anon1 wrote:
Each of the balls in a jar is either red, green or blue. If one ball is removed at random, what is the probability that the ball will be green?
(1) There are 7 blue balls in the jar.

(2) The probability that the ball will be red is 1/4


[Reveal] Spoiler:
I thought this was C because I thought having number of blue balls would close the unknown down to exact numbers. Where am I mistaken? Is there a way to think through this in an elegant manner?


Hii anon.
The probability that is given is just a kind of ratio in that R/(R+B+G)=1/4. If you combine this with # of B balls, then also there is not sufficient info to get the EXACT number of green balls.
There can be several numbers that can satisfy both the statements.
+1 E.
_________________

Prepositional Phrases Clarified|Elimination of BEING| Absolute Phrases Clarified
Rules For Posting
www.Univ-Scholarships.com

2 KUDOS received
Director
Director
User avatar
Status: Done with formalities.. and back..
Joined: 15 Sep 2012
Posts: 646
Location: India
Concentration: Strategy, General Management
Schools: Olin - Wash U - Class of 2015
WE: Information Technology (Computer Software)
Followers: 35

Kudos [?]: 357 [2] , given: 23

GMAT ToolKit User Premium Member
Re: Each of the balls in a jar is either red, green or blue. If [#permalink] New post 30 Nov 2012, 20:17
2
This post received
KUDOS
anon1 wrote:
Each of the balls in a jar is either red, green or blue. If one ball is removed at random, what is the probability that the ball will be green?
(1) There are 7 blue balls in the jar.

(2) The probability that the ball will be red is 1/4


[Reveal] Spoiler:
I thought this was C because I thought having number of blue balls would close the unknown down to exact numbers. Where am I mistaken? Is there a way to think through this in an elegant manner?


The easiest way to think through is always the most basic way. For knowing probability of anything we need to know favourable and total outcomes, in this case number of green balls and total balls. Or probability of it not happening ie not favorable/total in this case number of red+blue and total balls.

In the given question
Statement 1 doesnt help to get total or green ball or red+blue. Insufficient
Statement 2 gives only red/total. Insufficient
Combining these two we still can not find red+blue/total or green/total.

Therefore Ans E it is.
_________________

Lets Kudos!!! ;-)
Black Friday Debrief

Manager
Manager
avatar
Joined: 10 Sep 2012
Posts: 151
Followers: 2

Kudos [?]: 33 [0], given: 17

Re: Each of the balls in a jar is either red, green or blue. If [#permalink] New post 02 Dec 2012, 07:59
Ah. yes. this was easy once I wrote out 1/4 and then 25/100, which gives an unlimited amount of numbers for which "red" could have been. Thanks guys!
Re: Each of the balls in a jar is either red, green or blue. If   [#permalink] 02 Dec 2012, 07:59
    Similar topics Author Replies Last post
Similar
Topics:
Each of the 25 balls in a certain box is either red, blue, positive soul 4 26 Sep 2006, 18:09
Each of the 25 balls in a certain bax is either red, blue, uvs_mba 9 20 Sep 2006, 18:01
Each of 25 balls in a certain box is either red, blue, or GMATT73 13 30 Aug 2006, 02:04
Each of the 25 balls in a certain box are either red, blue jodeci 3 07 Apr 2006, 19:32
Each of 25 balls in a box are either blue, red, white and Jennif102 8 10 Oct 2005, 08:10
Display posts from previous: Sort by

Each of the balls in a jar is either red, green or blue. If

  Question banks Downloads My Bookmarks Reviews Important topics  


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

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®.