The present study is concerned with the concept of simulation and the development of simulation models, transposed into mathematical formalism from engineering sciences into economic context, as a powerful and effective tool for managerial decision making. The applications under consideration involve deterministic systems with continuous time and states, as well as with discrete ones. There presented simulations are of type G/G/1 activity, considered to be representative for models of modern business-type of problems, as well as paradigms, concepts and the mathematical formalism from engineering sciences, which have been successfully applied to economic organization-type problems, such as the Pollaczek – Khinchin formula, Lindley’s equatio...