Magtanong at makakuha ng eksaktong mga sagot sa IDNStudy.com. Ang aming platform ay nagbibigay ng mga maaasahang sagot upang matulungan kang gumawa ng matalinong desisyon nang mabilis at madali.

if C(n, 4) =126, what is n ?

Sagot :

C(n,4) = 126

To solve, we need to use combination formula:
          [tex]nCr = \frac{n!}{(n-r)! r!} [/tex]
Substitute the given, the solve;
          [tex] \frac{n!}{(n-4)!4!}=126 [/tex]
          [tex] \frac{n!}{(n-4)! 24} =126 [/tex]
          [tex] \frac{n!}{(n-4)!}=126(24) [/tex]
          [tex] \frac{n!}{(n-4)!} = 3024 [/tex]
          [tex] \frac{n(n-1)(n-2)(n-3)(n-4)!}{(n-4)!} = 9(8)(7)(6) [/tex]
Cancel (n-4)! since it is common to both numerator and denominator.
So,
         [tex]n(n-1)(n-2)(n-3) = 9(8)(7)(6)[/tex]

Since the left side has the same pattern with the right side, then it follows that n = 9. 
 For more learning about combination: https://brainly.ph/question/504738