We present a simple pair correlated wave function approach and use it to obtain results for the ground state densities and momentum distribution of a one-dimensional three-body bosonic system with different interactions in a harmonic trap. For equal interactions this approach is able to reproduce the known analytical cases of zero and infinite repulsion. We show that our results for the correlations agree with the exact diagonalization in all interaction regimes and with analytical results for the strongly repulsive impurity. It also enables us to access the more complicated cases of mixed interactions, and their effects on the probability densities are analyzed.