  Aims. Determination of the present evolutionary state and the restrictions on
the initial mass ratios of RZ Cas, KO Aql and S Equ. Methods. Comparison of
mass gaining stars with evolutionary models of single stars with the same mass
and subsequent comparison with accretion tracks from simultaneous conservative
binary evolution. Results. The gainers are in an early main sequence stage (Xc
greater than 0.5), with KO Aql being almost unevolved (assuming quasi-thermal
equilibrium). The initial donor/gainer mass ratios Mdi/Mgi must be larger than
three to obtain the present mass and luminosity of the gainers.
