A simple molecular model of dilute aqueous solutions based on an extended primitive model of water is examined. Theoretical calculations of solubility of nonpolar fluids and related properties do not make use of any a priori knowledge of the properties of water and do not resort to computer simulation results. It is shown that the model reproduces correctly characteristic temperature dependencies associated with hydrophobic hydration and consequently, unlike existing equations of state, also a maximum of the Henry's law constant at low temperatures. These results are analyzed in detail and for better understanding compared with those for a simple fluid solvent.