Question

if 2nC3=11nC3, find n​

Answer 1

Step-by-step explanation:

hey dear,. here is ur answer.. :) 2nc3= 11nc3. > 2n(2n-1)(2n-2)=11n(n-1)(n-2) ( in this 3 factorial will cancel out both side).

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Answer 2

Answer:

Step-by-step explanation:

$2nC_{3}$$=11nC_{3}$ find n.

Given that,

$2nC_{3}$$=11nC_{3}$

find n = ?

By using this formule,

$nC_{r} = \frac{n!}{r!(n-r)!}$

⇒ $\frac{2n!}{3!(2n-3)!}= \frac{11n!}{3!(n-3)!}$

⇒ $\frac{2n(2n-1)(2n-2)(2n-3)!}{3!(2n-3)!}= \frac{11n(n-1)(n-2)(n-3)!}{3!(n-3)!}$

⇒ ${2n(2n-1)(2n-1)=11n(n-1)(n-2)}$

⇒ ${4n(2n-1)=11n(n-2)}$

⇒ ${8n-4=11n-22$

⇒ ${-4+22=11n-8n$

⇒ $18=3n$

⇒ $n=\frac{18}{3}$

⇒ $n=6$

Hence proved  $n=6$.

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