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combination rules

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Intern
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combination rules  [#permalink]

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New post Updated on: 20 Sep 2018, 13:01
What is the solution of nC4 < 3Cn ?

A n>7
B n<7
C n>4
D n<3
E n>1


Originally posted by Godsent on 09 Sep 2018, 10:57.
Last edited by Godsent on 20 Sep 2018, 13:01, edited 3 times in total.
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Re: combination rules  [#permalink]

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New post 14 Sep 2018, 08:44
please update OA and source of the question.
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Re: combination rules  [#permalink]

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New post 17 Sep 2018, 14:01
nc4<3cn

n!/4![n-4]!<n!/3![n-3]!

n(n-1)(n-2)(n-3)/4!<n(n-1)(n-2)/3!

(n-3)/24<1/6

n-3<4

n<7
This is the answer,but I have doubts about the question.
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Re: combination rules  [#permalink]

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New post 17 Sep 2018, 21:01
Godsent wrote:
nc4<3cn

n!/4![n-4]!<n!/3![n-3]!

n(n-1)(n-2)(n-3)/4!<n(n-1)(n-2)/3!

(n-3)/24<1/6

n-3<4

n<7
This is the answer,but I have doubts about the question.


In Question, it is specified 3Cn
GMAT Club Bot
Re: combination rules &nbs [#permalink] 17 Sep 2018, 21:01
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