Question

nC6=nC8 then the value of n is​

Answer 1

kuch aata nahi kahi pe kuch bi likh dene ka nahi

Answer 2

The value of n is​ 14.

Given: nC6 = nC8.

To Find: The value of n.

Solution:

• We know that we can solve nCr by the formula,

         nCr = n! / ( r! × ( n - r )! )

Coming to the numerical, we are given;

        nC6 = nC8

    ⇒  n! / ( 6! × ( n - 6 )! ) = n! / ( 8! × ( n - 8 )! )

    ⇒  ( n - 8 )! / ( n - 6 )!  =  6! / 8!

    ⇒  ( n - 8 )! / [( n - 6 )×( n - 7 )×( n - 8 )! ] =  6 ! / ( 8 × 7 × 6! )

    ⇒   1 / [( n - 6 )×( n - 7 )] = 1 / ( 8×7 )

    ⇒ ( n - 6 ) × ( n - 7 ) = 56

    ⇒  n² - 13n - 14 = 0

    ⇒  n = -1, 14

n cannot be negative so n ≠ -1.

So, n = 14.

Hence, the value of n is​ 14.

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