Q. 64.3( 7 Votes )

# If ^{2n}C_{3}: ^{n}C_{3} = 12 : 1, find n.

Answer :

Given: ^{2n}C_{3}: ^{n}C_{3} = 12 : 1

To find: n=?

^{2n}C_{3}: ^{n}C_{3} = 12 : 1

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⇒2n-1=3(n-2)

⇒2n-1=3n-6

⇒n=6-1=5

Ans:n=5

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