A version of the discrete-ordinates method is used to solve in a unified manner some classical flow problems based on the Bhatnagar, Gross and Krook model in the theory of rarefiedgas dynamics. In particular, the thermal-creep problem and the viscous-slip (Kramers') problem are solved for the case of a semi-infinite medium, and the Poiseuille-flow problem, the Couetteflow problem and the thermal-creep problem are all solved for a wide range of the Knudsen number.