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

It is currently 21 Aug 2014, 16:14

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

A bag contains 10 balls, each of which is labeled with a

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Senior Manager
Senior Manager
User avatar
Joined: 25 Nov 2006
Posts: 337
Schools: St Gallen, Cambridge, HEC Montreal
Followers: 2

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

GMAT Tests User
A bag contains 10 balls, each of which is labeled with a [#permalink] New post 03 Jan 2008, 08:10
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 1 sessions
A bag contains 10 balls, each of which is labeled with a distinct
prime number. If 2 balls are to be removed from the bag and
the numbers on the balls are multiplied together, how many
different products are possible?


(A) 10
(B) 45
(C) 50
(D) 90
(E) It cannot be determined from the infomation given.
Director
Director
avatar
Joined: 09 Jul 2005
Posts: 595
Followers: 2

Kudos [?]: 19 [0], given: 0

GMAT Tests User
Re: PS Question [#permalink] New post 03 Jan 2008, 09:00
All the possible combinations of ten elements combined in groups of two elements which is 10!/[8!2!]=45 B
Director
Director
User avatar
Joined: 12 Jul 2007
Posts: 867
Followers: 12

Kudos [?]: 195 [0], given: 0

GMAT Tests User
Re: PS Question [#permalink] New post 03 Jan 2008, 09:24
Yup, same thing as thinking "I have 10 choices for my first pick and 9 for my second"

10*9 = 90

but the order doesn't matter since they're just being multiplied by one another. So divide by 2 to get rid of any duplicates (e.g. (3,5) and (5,3))

90/2 = 45

and there's your answer.

The original combination approach is the more correct way to go about it, but using permutations and modifying it works just as well.
SVP
SVP
avatar
Joined: 28 Dec 2005
Posts: 1593
Followers: 2

Kudos [?]: 68 [0], given: 2

GMAT Tests User
Re: PS Question [#permalink] New post 03 Jan 2008, 17:05
I went for 90 :(

forgot that the question asked for "different" products ! The answer should be half of 90 . i.e. 45
CEO
CEO
User avatar
Joined: 29 Mar 2007
Posts: 2593
Followers: 16

Kudos [?]: 183 [0], given: 0

GMAT Tests User
Re: PS Question [#permalink] New post 04 Jan 2008, 00:06
10!/8!2! --> 45

You can check this by lining up the primes: well just call them A-J

ABCDEFGHIJ
ABCDEFGHIJ draw lines from A to B to C etc.. then do the same for B but not drawing a line to either B or A.
Manager
Manager
User avatar
Joined: 04 Jan 2008
Posts: 85
Followers: 1

Kudos [?]: 10 [0], given: 0

Re: PS Question [#permalink] New post 05 Jan 2008, 06:09
45,
there are two places available and we know= possible first place x possible second place
so, 10 x 9, divide by 2 and get 45
Re: PS Question   [#permalink] 05 Jan 2008, 06:09
    Similar topics Author Replies Last post
Similar
Topics:
1 A bag contains six tokens, each labeled with one of the inte avohden 4 27 Nov 2013, 21:15
4 A bag contains 3 red and 2 black ball PiyushK 6 07 Aug 2013, 03:41
1 Experts publish their posts in the topic A bag contains a total of four billiard balls. The billiard slingfox 7 25 Oct 2009, 23:39
A bag contains 10 jelly beans, 9 of which are purple. A kevincan 3 07 Oct 2007, 09:15
A bag contains 10 coins, 9 of which are fair coins. The kevincan 4 22 Sep 2006, 13:40
Display posts from previous: Sort by

A bag contains 10 balls, each of which is labeled with a

  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®.