Question

What is the value of _8C_6?
(Points : 1)
28

48

2520

20,160

Answer 1

@whpalmer4

Answer 2

\[a\text{C}b = \left(
\begin{array}{c}
a \\
b \\
\end{array}
\right) = \frac{a!}{b!(a-b)!}\]
\[8C6 = \frac{8!}{6!(8-6)!} = \frac{8*7*6*5*4*3*2*1}{6*5*4*3*2*1*2*1} = \frac{8*7\cancel{*6*5*4*3*2*1}}{\cancel{6*5*4*3*2*1*}2*1} \]\[\qquad= \frac{8*7}{2*1} =\]