  Kinetic equations for quarks and gluons are solved numerically in the
relaxation time approximation for the case of one-dimensional boost-invariant
geometry. Quarks are massive and described by the Fermi-Dirac statistics, while
gluons are massless and obey Bose-Einstein statistics. The conservation laws
for the baryon number, energy, and momentum lead to two Landau matching
conditions which specify the coupling between the quark and gluon sectors and
determine the proper-time dependence of the effective temperature and baryon
chemical potential of the system. The numerical results illustrate how a
non-equlibrium mixture of quarks and gluons approaches hydrodynamic regime
described by the Navier-Stokes equations with appropriate forms of the kinetic
coefficients. The shear viscosity of a mixture is the sum of the shear
viscosities of quark and gluon components, while the bulk viscosity is given by
the formula known for a gas of quarks, however, with the thermodynamic
variables characterising the mixture. Thus, we find that massless gluons
contribute in a non-trivial way to the bulk viscosity of a mixture, provided
quarks are massive. We further observe the hydrodynamization effect which takes
place earlier in the shear sector than in the bulk one. The numerical studies
of the ratio of the longitudinal and transverse pressures show, to a good
approximation, that it depends on the ratio of the relaxation and proper times
only. This behaviour is connected with the existence of an attractor solution
for conformal systems.
