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

It is currently 13 Jul 2014, 21:30

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

Karen has exactly 6 quarters, 5 dimes, and 10 nickels in her

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Manager
Manager
avatar
Joined: 14 Oct 2008
Posts: 160
Followers: 1

Kudos [?]: 24 [0], given: 0

Karen has exactly 6 quarters, 5 dimes, and 10 nickels in her [#permalink] New post 04 Nov 2008, 12:29
Karen has exactly 6 quarters, 5 dimes, and 10 nickels in her pocket. If she withdraws a number of these coins at random, how many coins would she have to withdraw to ensure that she has at least a 50 percent chance of withdrawing at least one quarter?

1
2
5
6
7
Please explain your approach while answering. Thanks.
Senior Manager
Senior Manager
User avatar
Joined: 04 Aug 2008
Posts: 379
Followers: 5

Kudos [?]: 22 [0], given: 1

GMAT Tests User
Re: probability ..confusing [#permalink] New post 04 Nov 2008, 12:59
I would guess 2 on this

will explain after OA is posted cuz i am not sure about this one
_________________

The one who flies is worthy. The one who is worthy flies. The one who doesn't fly isn't worthy

Intern
Intern
User avatar
Joined: 14 Sep 2003
Posts: 46
Location: california
Followers: 1

Kudos [?]: 14 [0], given: 0

Re: probability ..confusing [#permalink] New post 04 Nov 2008, 16:09
me thinks B as well and here's how

6 quarters, 5 dimes and 10 nickels. If she were to pick 1 coin, the probability of it being a quarter is 6 / 21 ~ .28

Assume the first coin was a dime or a nickel. Now she picks one more coin and the resulting probability for a quarter is 6 / 20 = .3

Since they are discrete events, adding the 2 probabilities, yields 0.28 + 0.3 which is a little more than 50%. Is that the OA?

Gamecode - what is the source of this question? I'm trying to work on some Probability / combinations type problems and would appreciate a pointer to any good source. Thanks!
_________________

excellence is the gradual result of always striving to do better

Senior Manager
Senior Manager
User avatar
Joined: 04 Aug 2008
Posts: 379
Followers: 5

Kudos [?]: 22 [0], given: 1

GMAT Tests User
Re: probability ..confusing [#permalink] New post 04 Nov 2008, 17:53
same logic for my answer..
_________________

The one who flies is worthy. The one who is worthy flies. The one who doesn't fly isn't worthy

Manager
Manager
avatar
Joined: 14 Oct 2008
Posts: 160
Followers: 1

Kudos [?]: 24 [0], given: 0

Re: probability ..confusing [#permalink] New post 05 Nov 2008, 02:09
Choice B is correct and so is the explanation. The source is kaplan.
Re: probability ..confusing   [#permalink] 05 Nov 2008, 02:09
    Similar topics Author Replies Last post
Similar
Topics:
Karen has exactly 6 quarters, 5 dimes, and 10 nickels in her bschool83 2 07 Aug 2011, 13:10
3 Experts publish their posts in the topic A nickel, a dime, and 2 identical quarters are arranged marcodonzelli 6 31 Jan 2008, 21:22
A hand purse contains 6 nickels, 5 pennies and 4 dimes. What freetheking 6 25 Jul 2006, 20:52
Karen has exactly 6 quarters, 5 dimes, and 10 nickels in her Professor 14 11 May 2006, 20:21
Karen has exactly 6 quarters, 5 dimes, and 10 nickels in her Seth88 11 19 Dec 2004, 00:51
Display posts from previous: Sort by

Karen has exactly 6 quarters, 5 dimes, and 10 nickels in her

  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®.