#### Answer

$\displaystyle \frac{n!}{(n-r)!r!}$

#### Work Step by Step

The number of combinations possible if $r$ items
are taken from $n$ items is
${}_{n}C_{r}=\displaystyle \frac{n!}{(n-r)!r!}$.

Published by
Pearson

ISBN 10:
0321867327

ISBN 13:
978-0-32186-732-2

$\displaystyle \frac{n!}{(n-r)!r!}$

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