please explain it step by step include equation

15. Table 7.8 contains data for the installation of new equip ment in a manufacturing process at Excello Corporation. Your company is responsible for the installation project. Indirect costs are $15,000 per week, and a penalty cost of $9,000 per week will be incurred by your company for every week the project is delayed beyond week 9. a. What is the shortest time duration for this project regardless of cost? b. What is the minimum total cost associated with completing the project in 9 weeks? c. What is the total time of the minimum-cost schedule? TABLE 7.8 DATA FOR THE EQUIPMENT INSTALLATION PROJECT Activity Immediate Predecessor(s) Normal Time (wks) Crash Time (wks) A 2 1 B to 2 Normal Cost ($) 7,000 Crash Cost (5) 10,000 3,000 2 A 3 1 40,000 D B 3 2 3,000 12,000 12,000 8,000 5,000 9,000 28,000 8,000 E 1 1 F 5 3 3 15,000 DE E G *3 2 18,000