Answer:
The answer is "[tex]\bold{n_{C_{k}}}\\[/tex]"
Step-by-step explanation:
[tex]\to {n_{C_{k}}} = \frac{n!}{K! (n-k)!}[/tex]
For Example:
if n=5 and k=2
[tex]\to {5_{C_{2}}} = \frac{5!}{2! (5-2)!}[/tex]
[tex]= \frac{5!}{2! (3)!}\\\\= \frac{5!}{2! \times 3!}\\\\= \frac{5 \times 4 \times 3 \times 2 \times 1}{2 \times 1 \times 3 \times 2 \times 1}\\\\= \frac{5 \times 4 }{2 \times 1 } \\\\= \frac{5 \times 4 }{2} \\\\= 5 \times 2 \\\\= 10 \\\\[/tex]
