Respuesta :
The correct answer is:
36.
Explanation:
This is a combination of 9 items taken 2 at a time (order is not important). This is given by the formula:
[tex] _nC_r=\frac{n!}{(n-r)!r!}
\\
\\_9C_2=\frac{9!}{(9-2)!2!}=\frac{9!}{7!2!}=36 [/tex]
The correct answer is:
36.
Explanation:
This is a combination of 9 items taken 2 at a time (order is not important). This is given by the formula:
[tex] _nC_r=\frac{n!}{(n-r)!r!}
\\
\\_9C_2=\frac{9!}{(9-2)!2!}=\frac{9!}{7!2!}=36 [/tex]
