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combination question
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19 Nov 2016, 12:24
19 Nov 2016, 12:24
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Question Stats:
100% (02:46) correct
0% (00:00) wrong based on 2 sessions
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ben needs to form a committee of 3 from a group of 8 engineers to study design improvements for a product. if two of the engineers are too inexperienced to serve together on the committee , how many different committees can ben form?
Re: combination question
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19 Nov 2016, 12:58
19 Nov 2016, 12:58
1
Expert Reply
Break this into 2 cases
Case1: No inexperienced engineers
total no of engg available= 6
no to be selected = 3
No of ways= 6C3= 20
Case2: One in-experienced engg
no of ways selecting one in-exp engg =2
no of ways of selecting other 2 guys = 6C2 = 30
So total no of ways = 2 *15 = 30
So total no of combinations = case 1 + case 2 = 20+30 =50
PS Share the OA and source
Case1: No inexperienced engineers
total no of engg available= 6
no to be selected = 3
No of ways= 6C3= 20
Case2: One in-experienced engg
no of ways selecting one in-exp engg =2
no of ways of selecting other 2 guys = 6C2 = 30
So total no of ways = 2 *15 = 30
So total no of combinations = case 1 + case 2 = 20+30 =50
PS Share the OA and source
Re: combination question
[#permalink]
19 Nov 2016, 13:48
19 Nov 2016, 13:48
sandy wrote:
Break this into 2 cases
Case1: No inexperienced engineers
total no of engg available= 6
no to be selected = 3
No of ways= 6C3= 120
Case2: One in-experienced engg
no of ways selecting one in-exp engg =2
no of ways of selecting other 2 guys = 6C2 = 30
So total no of ways = 2 *30 = 60
So total no of combinations = case 1 + case 2 = 120+60 =180
PS Share the OA and source
Case1: No inexperienced engineers
total no of engg available= 6
no to be selected = 3
No of ways= 6C3= 120
Case2: One in-experienced engg
no of ways selecting one in-exp engg =2
no of ways of selecting other 2 guys = 6C2 = 30
So total no of ways = 2 *30 = 60
So total no of combinations = case 1 + case 2 = 120+60 =180
PS Share the OA and source
sandy , thanks for the reply . but the answer is 50 as per the book. which one is correct 50 or 180 .
