[en] The nonleptonic decays of K-mesons and hyperons are considered within the framework of the valence quark approximation. The general form of the Hamiltonian is used. In particular, the possibility of V+A currents coupling heavy and light quarks is taken into account. The coefficients in the effective Hamiltonian expansion are estimated basing on the calculation of the strong interactions and are fixed finally in some cases using the experimental data. The conclusion is that the Δ I=1/2 rule is most likely to be due to the effective S, P coupling arising from the account of strong interactions in all the models of weak interaction. Several relations are obtained which result from this explanation of the ΔI=1/2 rule and they are found to be in agreement with data. The unique predictions for the ΔI=3/2 transitions are also obtained. Throughout the paper the quark masses (which characterize the SU(2)xSU(2) symmetry breaking) are assumed to be small. According to the estimates neither strong interaction enhancement of the ΔI=1/2 piece of the Hamiltonian, nor the (V+A) currents are essential for the understanding of the ΔI=1/2 rule