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Intern
Joined: 02 Jun 2009
Posts: 26
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Question Stats:
0% (00:00) correct
 0% (00:00) wrong based on 0 sessions
If a committee of 3 people is to be selected from among 5 married couples so that the committee does not include two people who are married to each other, how many such committees are possible?
A. 20
B. 40
C. 50
D. 80
E. 120
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CEO
Joined: 17 Nov 2007
Posts: 3591
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40
Followers: 230
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D1) C^5_3 - we choose 3 couples out of 5 couples. 2) (C^2_1)^3 - we choose one spouse for each couple. 3) total number = C^5_3*(C^2_1)^3 = 10*8 = 80
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Senior Manager
Joined: 16 Jan 2009
Posts: 351
Location: United States
GMAT 1: 710 Q50 V35
GPA: 3
WE: Sales (Telecommunications)
Followers: 2
Kudos [?]:
55
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80 = 5C3*(2C1)(2C1)(2C1) IMO D
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Lahoosaher
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Senior Manager
Joined: 15 Jan 2008
Posts: 295
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i have a slightly diff approach which is simple..
when encountered with such questions.. i deduct the unwanted ways from teh total number of ways..
in this case, the total number of ways is 10c3 =>120.
unwanted ways = 5 * 8 (5 couples * select one from rest of the group ) = 40.
answer = 120 - 40 = 80
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close
