The Lockhead Aircraft Co. is ready to begin a project to develop a new fighter airplane for the U.S. Air Force. The company€™s contract with the Department of Defense calls for project completion within 92 weeks, with penalties imposed for late delivery.
The project involves 10 activities (labeled A, B, . . . ,J), where their precedence relationships are shown in the project network below.

Management would like to avoid the hefty penalties for missing the deadline in the current contract. Therefore, the decision has been made to crash the project, using the CPM method of time-cost trade-offs to determine how to do this in the most economical way. The data needed to apply this method are given next.

(a) Formulate a linear programming model for this problem.
(b) Use Excel to solve the problem.
(c) Use another software option to solve the problem.

START Activity Time Normal Crash Time Normal Cost Crash Cost 32 weeks28 weeks $160 million 180 million 28 weeks 25 weeks 125 million146 million 36 weeks 3 eeks 10 mlion210 million 16 weeks13 eeks 60 mlion72 million 32 weeks 27 weeks 135 milion160 million 54 weeks 47 weeks 215 milion257 million 17 weeks 15 weeks 90 million 96 million 20 weeks 7 weeks 120 million132 million 34 weeks 30 eeks 190 milion226 million 18 weeks 16 weeks 80 million 84 million 7 2