#### Answer

$C(100, 1) = 100$

#### Work Step by Step

RECALL:
$C(n, r) = \dfrac{n!}{r!(n-r)!}$
Use the formula above to obtain:
$C(100, 1) = \dfrac{100!}{1!(100-1)!}
\\C(100, 1)) = \dfrac{100!}{1!(99!!)}
\\C(100, 1) = \dfrac{100!(1)}{99!}
\\C(100, 1) = \dfrac{100!}{99!}
\\C(100, 1) = \dfrac{100(99!)}{99!}
$
Cancel the common factors to obtain:
$\require{cancel}
\\C(100, 1) = \dfrac{100\cancel{(99!)}}{\cancel{99!}}
\\C(100, 1) = 100$