# Chapter 12 - Counting and Probability - Section 12.2 Permutations and Combinations - 12.2 Assess Your Understanding - Page 875: 19

$C(15,15) = 1$

#### Work Step by Step

We know, $C(n,r) = \dfrac{n!}{(n-r)!r!}$ In this case, $C(15,15) \\= \dfrac{15!}{(15-15)!\times15!} \\= \dfrac{15!}{0!\times15!} \\=\dfrac{15!}{15!} \\=1$

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