Probability

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sparkle6: Senior | Next Rank: 100 Posts; Posts: 54; Joined: Tue Sep 20, 2011 7:58 amFollowed by: 1 member; Thanked: 1 times

by sparkle6 » Sun Sep 25, 2011 6:32 am

From a group of 3 boys and 3 girls, 4 children are to be randomly selected. What is the probability that equal numbers of boys and girls will be selected?

A. 1/10
B. 4/9
C. 1/2
D. 3/5
E. 2/3

[spoiler]Answer: D[/spoiler]

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Source: Beat The GMAT — Problem Solving | Sun Sep 25, 2011 6:32 am

shankar.ashwin: Legendary Member; Posts: 966; Joined: Sat Jan 02, 2010 8:06 amFollowed by: 21 members; Thanked: 230 times

by shankar.ashwin » Sun Sep 25, 2011 6:35 am

(3C2 * 3C2) / 6C4 = 3/5

3 of each type and 6 in total, you chose 2 from each and 4 in total from 6

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