The structure of colloidal solution with size asymmetric electrolytes using a solvent primitive model representation is investigated using density functional theory and Monte Carlo simulation. The solvent is assumed to be an individual component apart from its behavior as a countinuum dielectric medium. The theory is partially perturbative with hard-sphere correlation being treated using a weighted density approach, whereas the residual ionic contribution is calculated through perturbation around the uniform density. A standard canonical ensemble Monte Carlo simulation method is also adopted here, for comparison. The theoretical results are in quantitative agreement with the simulation data for the entire range of parametric conditions. This study points to the importance of including the solvent as an individual component.