The central focus of this book is not only to provide a formal quantitative approach to problem solving but also to give an insight for managerial and decision making situation in particular where a quantitative approach is appropriate. We believe that the only way to learn materials with mathematical approach as a tool for economic analysis or for managerial decision making is by working problems. Therefore, each chapter contains relevant questions and some worked examples to enable readers to conceptualize and understand better quantitative theories and its applications.