#### Answer

15.504

#### Work Step by Step

$20$C$5$ is equivalent with the following expression:
$\binom{20}{5} =\frac{20!}{5!\times (20-15)!}=\frac{15!\times16\times17\times18\times19\times20}{15!\times5!}=\frac{16\times17\times18\times19\times20}{5\times4\times3\times2\times1}=\frac{1.860.480}{120}=15.504$