My best is 74 chars (including newlines and sub c{}:

sub c{f($_[0],$_[0]-$_[1]+1) / f($_[1],1)} sub f{eval join'*',$_[1]..$_[0]} [download]

Take 2 (66 chars including both subs and newlines, 50 chars for just the sub bodies):

sub c{f($_[0]-$_[1]+1..$_[0])/f(1..$_[1])} sub f{eval join'*',@_} [download]

-ben