  The paper is devoted to investigation of $K$ mesons production in exclusive
$B_{c}$ decays $B_{c} \to \psi^{(')}K^{+}K^{-}\pi^{+}$ and $B_{c} \to
\psi^{(')}K^{+}\pi^{+}\pi^{-}$. In the framework of resonance approximation we
obtain theoretical predictions for branching fractions of these decays and
present distributions over different kinematical variables.
