When an accounting firm audits a corporation, the first phase of the audit involves obtaining knowledge of the business. This phase of the audit requires the activities listed in the file P15_30.xlsx.

a. Draw the AON project network and determine the critical path and the minimum number of days needed to complete the first phase of the audit.

Also, create the associated Gantt chart.

b. Assume that the first phase must be completed within 30 days. The duration of each activity can be reduced by incurring the costs listed in the file P15_30.xlsx. Find the strategy that minimizes the cost of meeting this deadline.