Given that we need to find the value of .

⇒

We know that ⁿC_r + ⁿC_{r + 1} = ^{n + 1}C_{r + 1}

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⇒

⇒

⇒

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We know that

And also n! = n(n – 1)(n – 2)…………2.1

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⇒

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⇒

∴ The value of is 42504.