If we just had faith and practice and no study, we could easily follow a blind faith, which is not grounded in real understanding.... If we just studied, without practice or faith, we would be following a theoretical and intellectual teaching (Flow 343, pp.19). We shall study while practice to have in depth understanding of the philosophy of life. I cannot answer other combination, but everything is lies within us. Think about the previous example about turn on/off the light. Have fun.