#### Answer

20

#### Work Step by Step

The number of possible combinations if r items are taken from n items is
nCr = $\frac{n!}{r!(n-r)!}$
The number of ways to select three city commissioners from a group of six candidates is:
6C3 = $\frac{6!}{3!(6-3)!}$
= $\frac{6*5*4*3!}{3!3!}$
=$\frac{6*5*4}{3*2*1}$
=5*4 =20 ways