Question

nc3=220 find the value of n

Answer 1

Answer:

12

Step-by-step explanation:

Given : $^nC_3=220$

To Find : Value of n

Solution:

$^nC_3=220$

Formula : $^nC_r=\frac{n!}{r!(n-r)!}$

Substitute r = 3

$^nC_3=\frac{n!}{3!(n-3)!}$

$220=\frac{n \times (n-1) \times (n-2) \times (n-3)!}{3!(n-3)!}$

$220=\frac{n \times (n-1) \times (n-2) }{3 \times 2 \times 1 }$

$220=\frac{n \times (n^2-2n-n+2) }{6}$

$1320=n \times (n^2-3n+2)$

$1320=n^3-3n^2+2n$

$n=12$

Hence the value of n is 12

Answer 2

Answer:

hope it is helpful to u

Step-by-step explanation:

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