My topic is PERT/ CPM that comes from the mentioned chapter. PERT stands for ‘Program Evaluation and Review Technique’; and, CPM stands for Critical Path Method. PERT is nothing but a tool (risk management tool) that helps to perform an estimation regarding when the project will be completed (the probable time). In the concept of PERT, there are ideas of optimistic or pessimistic approach. These approaches impacts the time and each of the alternatives is taken keeping in mind the scenario that is prevailing in the site of the project or the most probable scenario that may happen.