I'm unsure how to work out the combinations I'm having issues working out the answer to a question $C(6,2)$. I'm working it out wrong because I've got this
$$C(6,2) = \frac{6!}{2(6-2)!} = \frac{6!}{2\ 4!} = \frac{6!}{8!} = \frac{720}{40320} = 0.0178.$$

$${6\choose 2}={6!\over 2!(6-2)!}={6!\over 2!4!}={6\cdot5\cdot4!\over 4!2!}={6\cdot5\over 2!}={30\over 2}=15$$
