In this study, new model having rational properties with respect to salesadvertising relationship is proposed. With an empirical study, this model is analyzed in detail by comparison with the existing sales-advertising model. Extension to discrete-time versions of two continuous-time models(new model and the existing model) is also shown. In addition, in order to check the equilibrium and stability under optimal closed-loop systems of two models, the system analysis is performed. Then, taking into consideration interdependency of production and marketing departments, interdependent model based on new model of sales-advertising and HMMS model of production-inventory is developed. It is compared with separate models of advertising and production planning. Extension to discrete-time version is also shown. Though numerical examples, it is shown that simultaneous planning of advertising and production can result in significant savings.