#### Answer

1716

#### Work Step by Step

The number of possible combinations if r items are taken from n items is
nCr = $\frac{n!}{r!(n-r)!}$
Number of ways 6 people can be selected from 13 people who have volunteered for the test:
13C6= $\frac{13!}{6!(13-6)!}$
= $\frac{13!}{6!7!}$
= $\frac{13*12*11*10*9*8*7!}{6!7!}$
=$\frac{13*12*11*10*9*8}{6*5*4*3*2*1}$
= 1716 ways