## Thinking Mathematically (6th Edition)

The order of the chosen employees does not matter. Combinations: ${}_{n}C_{r}=\displaystyle \frac{n!}{(n-r)!r!}$ ${}_{6}C_{3}=\displaystyle \frac{6!}{(6-3)!3!}=\frac{6\times 5\times 4}{1\times 2\times 3}=20$