In this paper, sensitivity and duality analyses have been performed on our earlier developed optimal water treatment cost model for Ghana. Linear Programming was used to formulate the model and tested with real data collected from Weija Water Headworks in Accra using Interior-Point Method to obtain solutions. The effects of variations of selected key parameters on the developed model have now been investigated. Marginal costs of water production in the selected water headworks have also been found. It is strongly recommended that all Water Headworks under Ghana Water Company Limited (GWCL) should employ at least one Operations Researcher to assist them in some of these post-optimality analyses.
In this paper, the concept of Linear Programming (LP) was applied to Multigrow Insurance Company in Ghana which had a portfolio problem. The company had obtained GH₵ 200000 cash but had a difficulty in determining how much to invest in each of five investment areas in order to maximize return. Based on the data collected, the problem was formulated as a Linear Programming Problem and solved using Management Scientist Version 5 Software. Optimal portfolio mix was obtained for the Insurance Company. Finally, the total optimal return on the investments of the company was found to be GH₵ 15980. It is strongly recommended that the Company should adhere to the proposed optimal portfolio mix and also employ at least one operations researcher to assist the Company in its activities.
The transportation paradox is related to the classical transportation problem. For particular reasons of this problem, an increase in the quantity of goods to be transported may lead to a decrease in the optimal total transportation cost. In this paper, an efficient algorithm for solving a linear programming problem was discussed, and it was concluded that paradox exists. The North-West Corner method was used to obtain the optimal solution using the TORA Statistical Software Package. The method however gives a step by step development of the solution procedure for finding all the paradoxical pair