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A comittee of three people is to be chosen from four married

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Joined: 14 Feb 2012
Posts: 40

Kudos [?]: 42 [0], given: 13

Location: Germany
Concentration: Technology, Strategy
GMAT Date: 06-13-2012
A comittee of three people is to be chosen from four married [#permalink]

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New post 09 Apr 2012, 13:55
00:00
A
B
C
D
E

Difficulty:

  5% (low)

Question Stats:

90% (00:25) correct 10% (01:23) wrong based on 79 sessions

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Hey!

Can anybody help me with Combinatorics or especially with Factorials, I just don't get it (haven't gotten it in school also...).

I'm just watching the Thursdays with Ron video to this topic, so let's go with this example question:

A comittee of three people is to be chosen from four married couples. What is the number of different comittees that can be chosen if two people who are married to each other cannot both serve on the comittee.

A. 16
B. 24
C. 26
D. 30
E. 32


The right answer choice is E.

Steps to the answer:

- Set up the Slots -> _ _ _ (3 choices)
- put in the numbers and multiply: 8*6*4= 192
- Divide by Factorization <- That's where the problems come, can anybody explain how I get the Factorial I have to divide by?

Thanks in advance,

Andreas
[Reveal] Spoiler: OA

Kudos [?]: 42 [0], given: 13

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V
Joined: 02 Sep 2009
Posts: 41885

Kudos [?]: 128722 [0], given: 12182

Re: Concept of Combinatorics / Factorials [#permalink]

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New post 09 Apr 2012, 14:08
andih wrote:
Hey!

Can anybody help me with Combinatorics or especially with Factorials, I just don't get it (haven't gotten it in school also...).

I'm just watching the Thursdays with Ron video to this topic, so let's go with this example question:

A comittee of three people is to be chosen from four married couples. What is the number of different comittees that can be chosen if two people who are married to each other cannot both serve on the comittee.

A. 16
B. 24
C. 26
D. 30
E. 32


The right answer choice is E.

Steps to the answer:

- Set up the Slots -> _ _ _ (3 choices)
- put in the numbers and multiply: 8*6*4= 192
- Divide by Factorization <- That's where the problems come, can anybody explain how I get the Factorial I have to divide by?

Thanks in advance,

Andreas


This question is discussed here: a-committee-of-3-people-is-to-be-chosen-from-four-married-94068.html (Your question about division by factorial is also addressed in that topic) In case of any question please post it in that thread.

Similar questions to practice:
if-a-committee-of-3-people-is-to-be-selected-from-among-98533.html
ps-combinations-94068.html
ps-combinations-101784.html
committee-of-88772.html
if-4-people-are-selected-from-a-group-of-6-married-couples-99055.html
if-there-are-four-distinct-pairs-of-brothers-and-sisters-99992.html

Hope it helps.
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Kudos [?]: 128722 [0], given: 12182

Re: Concept of Combinatorics / Factorials   [#permalink] 09 Apr 2012, 14:08
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A comittee of three people is to be chosen from four married

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