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A student council is to be chosen from a class of 12 students consisti
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03 Jan 2019, 10:42
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52% (01:21) correct 48% (01:01) wrong based on 60 sessions
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Re: A student council is to be chosen from a class of 12 students consisti
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03 Jan 2019, 10:47
A student council is to be chosen from a class of 12 students consisting of a president, a vice president, and 3 committee members. How many such councils are possible Choosing 5 members from 12 = 12C5 = 12!/ (7! 5!) Answer Option A is Correct.
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Re: A student council is to be chosen from a class of 12 students consisti
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03 Jan 2019, 11:30
UB001 wrote: A student council is to be chosen from a class of 12 students consisting of a president, a vice president, and 3 committee members. How many such councils are possible
Choosing 5 members from 12 = 12C5 = 12!/ (7! 5!) Answer Option A is Correct. Wouldn't this need to be a permutation because of the different positions? That would be 12!/7!, but adjust for 3 positions being the same 12!/(7!3!). I'm not certain, but that is my initial thought. Posted from my mobile device



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A student council is to be chosen from a class of 12 students consisti
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03 Jan 2019, 19:37
kanakdaga wrote: nmccull wrote: UB001 wrote: A student council is to be chosen from a class of 12 students consisting of a president, a vice president, and 3 committee members. How many such councils are possible
Choosing 5 members from 12 = 12C5 = 12!/ (7! 5!) Answer Option A is Correct. Wouldn't this need to be a permutation because of the different positions? That would be 12!/7!, but adjust for 3 positions being the same 12!/(7!3!). I'm not certain, but that is my initial thought. Posted from my mobile deviceI think so too. a permutation problem is one that is dependent on arrangement. That means : (a,b) is not equal to (b,a). A combinations problem is one where (a,b) = (b,a). Here, we are choosing 5 people out of 12. But a person chosen for president will be a separate combination than to the person chosen as vice president. Thus, arrangement matters. so its a permutations problem. thus 12P5



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A student council is to be chosen from a class of 12 students consisti
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03 Jan 2019, 19:51
"I think so too. a permutation problem is one that is dependent on arrangement. That means : (a,b) is not equal to (b,a). A combinations problem is one where (a,b) = (b,a). Here, we are choosing 5 people out of 12. But a person chosen for president will be a separate combination than to the person chosen as vice president. Thus, arrangement matters. so its a permutations problem. thus 12P5"
Yes I am pretty confident it is a permutation, but does it need to be adjusted for the fact that there are only 3 unique positions? 12p5 implies 5 unique positions for arrangement, but there are only 3 in this case (president, vice president, and council member).
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Re: A student council is to be chosen from a class of 12 students consisti
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03 Jan 2019, 20:13
nmccull wrote: "I think so too. a permutation problem is one that is dependent on arrangement. That means : (a,b) is not equal to (b,a). A combinations problem is one where (a,b) = (b,a). Here, we are choosing 5 people out of 12. But a person chosen for president will be a separate combination than to the person chosen as vice president. Thus, arrangement matters. so its a permutations problem. thus 12P5"
Yes I am pretty confident it is a permutation, but does it need to be adjusted for the fact that there are only 3 unique positions? 12p5 implies 5 unique positions for arrangement, but there are only 3 in this case (president, vice president, and council member).
Posted from my mobile device You mean that choosing the council members would be a combination while for the three positions it is a permutation ? lets consider people : a , b, c ,d, e a as president = 1 way a as vice president = 1way a,b,c as council members = 1 way but a,b,c = b, c, a = c, a, b thus 3 positions as permutation ?



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Re: A student council is to be chosen from a class of 12 students consisti
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03 Jan 2019, 20:23
kanakdaga wrote: nmccull wrote: "I think so too. a permutation problem is one that is dependent on arrangement. That means : (a,b) is not equal to (b,a). A combinations problem is one where (a,b) = (b,a). Here, we are choosing 5 people out of 12. But a person chosen for president will be a separate combination than to the person chosen as vice president. Thus, arrangement matters. so its a permutations problem. thus 12P5"
Yes I am pretty confident it is a permutation, but does it need to be adjusted for the fact that there are only 3 unique positions? 12p5 implies 5 unique positions for arrangement, but there are only 3 in this case (president, vice president, and council member).
Posted from my mobile device You mean that choosing the council members would be a combination while for the three positions it is a permutation ? lets consider people : a , b, c ,d, e a as president = 1 way a as vice president = 1way a,b,c as council members = 1 way but a,b,c = b, c, a = c, a, b thus 3 positions as permutation ? Yes, that is how I interpreted the scenario.



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A student council is to be chosen from a class of 12 students consisti
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03 Jan 2019, 20:51
nmccull wrote: kanakdaga wrote: nmccull wrote: "I think so too. a permutation problem is one that is dependent on arrangement. That means : (a,b) is not equal to (b,a). A combinations problem is one where (a,b) = (b,a). Here, we are choosing 5 people out of 12. But a person chosen for president will be a separate combination than to the person chosen as vice president. Thus, arrangement matters. so its a permutations problem. thus 12P5"
Yes I am pretty confident it is a permutation, but does it need to be adjusted for the fact that there are only 3 unique positions? 12p5 implies 5 unique positions for arrangement, but there are only 3 in this case (president, vice president, and council member).
Posted from my mobile device You mean that choosing the council members would be a combination while for the three positions it is a permutation ? lets consider people : a , b, c ,d, e a as president = 1 way a as vice president = 1way a,b,c as council members = 1 way but a,b,c = b, c, a = c, a, b thus 3 positions as permutation ? Yes, that is how I interpreted the scenario. check this question out. https://gmatclub.com/forum/aclubhas1 ... fl=similaryour reasoning sounds correct though.



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A student council is to be chosen from a class of 12 students consisti
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03 Jan 2019, 21:01
Bunuel wrote: A student council is to be chosen from a class of 12 students consisting of a president, a vice president, and 3 committee members. How many such councils are possible
(A) \(\frac{12!}{7!5!}\)
(B) \(\frac{12!}{7!3!}\)
(C) \(\frac{12!}{3!5!}\)
(D) \(\frac{12!}{7!}\)
(E) \(12!\) A president can be chosen in 12 ways. Vice president in 11 ways. Remaining 3 committee members can be selected in \(10_C_3\) ways = \(\frac{10!}{7!3!}\) So total possible ways are \(\frac{12!}{7!3!}\) OPTION: B
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Re: A student council is to be chosen from a class of 12 students consisti
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11 Jan 2019, 07:52
chetan2u or VeritasKarishma could you please explain how is it a Permutation problem? & the solution



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Re: A student council is to be chosen from a class of 12 students consisti
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11 Jan 2019, 08:35
Manat wrote: chetan2u or VeritasKarishma could you please explain how is it a Permutation problem? & the solution Hi .. It is a combination of permutation and combination.. Out of 12 you have to choose a president, vice president and 3 committee members.. So choosing president and vice president is permutation and selection of 3 committee members is combination. Go step by step.. 1) president  any of the 12, so 12 ways 2) vice president  any of the remaining 11, so 11 ways 3) 3 committee members  3 out of 10, so 10C3.. Total ways = \(12*11*10C3=12*11*\frac{10!}{7!3!}=\frac{12!}{7!3!}\) B
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1) Absolute modulus : http://gmatclub.com/forum/absolutemodulusabetterunderstanding210849.html#p1622372 2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html 3) effects of arithmetic operations : https://gmatclub.com/forum/effectsofarithmeticoperationsonfractions269413.html
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Re: A student council is to be chosen from a class of 12 students consisti &nbs
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