Answer
$C(18,1)=18$
Work Step by Step
Using the combination formula, we obtain:
$C(n,r)=\frac{n!}{(n-r)!r!}$
$C(18,1)=\frac{18!}{(18-1)!1!}=\frac{18!}{17!1!}=\frac{18\cdot17!}{17!\cdot1}=18$
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