If n+1C3=4nC2 then n=
Given that,n+1C3=4.nC2
Then n=?
n+1C3=4.nC2
⇒(n+1)!3!(n+1−3)!=4.n!2!(n−2)!
⇒(n+1)n!3×2!(n−2)!=4.n!2!(n−2)!
⇒(n+1)3=4
⇒n+1=12
⇒n=12−1=11
Hence, this is the answer.