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

It is currently 22 Jul 2014, 20:09

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

In a certain group of 10 members, 4 members teach only

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Manager
Manager
avatar
Joined: 17 Aug 2005
Posts: 167
Followers: 1

Kudos [?]: 15 [0], given: 0

In a certain group of 10 members, 4 members teach only [#permalink] New post 18 Oct 2005, 08:08
In a certain group of 10 members, 4 members teach only French and the rest teach only Spanish or German. If the group is to choose a 3-member committee, which must have at least 1 member who teaches French, how many different committees can be chosen?

(A) 40
(B) 50
(C) 64
(D) 80
(E) 100

Please explain
VP
VP
avatar
Joined: 22 Aug 2005
Posts: 1128
Location: CA
Followers: 1

Kudos [?]: 23 [0], given: 0

GMAT Tests User
 [#permalink] New post 18 Oct 2005, 08:28
E. 100

Possible combinations are:
1F & 2 Others
2F & 1 Other
3F & 0 Other

total combinations:
4c1 * 6c2 + 4c2 * 6c1 + 4c3 * 6c0 = 100
Director
Director
User avatar
Joined: 14 Oct 2003
Posts: 592
Location: On Vacation at My Crawford, Texas Ranch
Followers: 1

Kudos [?]: 4 [0], given: 0

GMAT Tests User
Re: Perms & Combs [#permalink] New post 18 Oct 2005, 08:36
kimmyg wrote:
In a certain group of 10 members, 4 members teach only French and the rest teach only Spanish or German. If the group is to choose a 3-member committee, which must have at least 1 member who teaches French, how many different committees can be chosen?

(A) 40
(B) 50
(C) 64
(D) 80
(E) 100

Please explain


Easiest and shortest way to solve a combination with a constraint is to

First Find the Total Combination w/o constraints

10 C 3 = 120

Find the Combination of NO French teachers 6 C 3 = 20

Subtract the the Combination of having no French teachers from the total

10C3-6C3=100

Less than 1.5 mins.
GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 07 Jul 2004
Posts: 5097
Location: Singapore
Followers: 16

Kudos [?]: 131 [0], given: 0

GMAT Tests User
 [#permalink] New post 18 Oct 2005, 08:37
We're given:

French - 4 members
Spanish or German - 6 members

The group of three must have at least 1 member who teaches French:

Three cases:

Case 1: 2 French member and 1 Spanish or German

4C2*6C1 = 36 combinations

Case 2: 1 French member and 2 Spanish or German
4C1*6C2 = 60 combinations

Case 3: 3 French members
4C3 = 4 combinations

Total = 100 combinations
  [#permalink] 18 Oct 2005, 08:37
    Similar topics Author Replies Last post
Similar
Topics:
Experts publish their posts in the topic In a certain group of 10 members, 4 memebers teach only CaspAreaGuy 3 19 Dec 2007, 03:55
from gmatprep In a certain group of 10 members, 4 members Tarmac 3 12 Dec 2007, 20:43
Another Q I missed... In a certain group of 10 members, 4 shmegs 8 12 Aug 2007, 03:35
In a certain group of 10 members, 4 members teach only jet1445 2 26 Feb 2007, 10:08
In a certain group of 10 members, 4 members teach only jylo 1 13 Feb 2007, 09:59
Display posts from previous: Sort by

In a certain group of 10 members, 4 members teach only

  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®.