EN
We present a study of the magnetic properties of a mixed ferro-ferrimag-netic ternary alloy of the type AB_p C_{1-p} on a cubic lattice consisting of three different Ising spins S_A =3/2, S_B = 2, and S_C = 5/2. We employ the mean-field approximation and Monte Carlo simulation to find the compensation temperatures of the system for selected values of the parameters in the model Hamiltonian. In particular, the relation between considered mixed ferro-ferrimagnetic model and magnetic properties of the ternary metal Prussian blue analog such as (Fe_p^{II}Mn_{1-p}^{II})_1.5 [Cr^{III}(CN)_6] · nH_2O is discussed.