Answer
$C(7,4) = 35$
Work Step by Step
Use the formula $C(n, r)=\dfrac{n!}{(n-r)!r!}$:
$C(7,4)
\\= \dfrac{7!}{(7-4)!4!}
\\= \dfrac{7!}{3!\times4!}
\\=\dfrac{7\times6\times5\times4!}{3!\times4!}
\\= \dfrac{7\times6\times5}{3\times2\times1}
\\= \dfrac{210}{6}
\\= 35$
