I need Help 2

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likewhoa: Senior | Next Rank: 100 Posts; Posts: 49; Joined: Sun Aug 12, 2007 8:17 pm

by likewhoa » Sun Nov 18, 2007 7:32 am

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

Answer: 3/5

Can anyone explain?

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Source: Beat The GMAT — Problem Solving | Sun Nov 18, 2007 7:32 am

ri2007: Master | Next Rank: 500 Posts; Posts: 258; Joined: Mon Aug 27, 2007 12:43 pm; Thanked: 15 times

Re: I need Help 2

by ri2007 » Sun Nov 18, 2007 8:19 am

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

Answer: 3/5

Can anyone explain?

Total Possible Outcomes i.e ways in which you can select 4 children from 6 = 6C4 = 15

Total way in which u can select 2 boys from 3 = 3C2 = 3
Total ways in which you can select 2 girls from 3 is 3C2 = 3
Total ways in which you can select 2 girls and 2 boys is 3 * 3 = 9

So P (2 boys + 2 girls ) = 9/15 = 3/5

P

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