Question 3 (25 marks) The table below indicates the precedence requirements, activity times, and normal and crash costs for a construction project. Activity Precedes Normal Time (weeks) Normal Cost 5 A B 4 C B, C D E, F GH H 3 D E + 6 4 Crashing Cost (s per week) Can crash activities 1 or 2 weeks; First Week Second Week $1200 $1200 1000 1000 1000 1100 500 500 750 750 1200 1200 1200 1200 1500 1500 1200 $7,000 5000 4000 10,000 9000 7000 9,000 8,000 10,000 6,000 F G . I 5 4 . 1 5 5 End End 6 + (a) (b) (c) Sketch a precedence network diagram to depict the project activities. (3 marks) Complete a forward and backward pass to determine the ES, EF, LS and LF times for each project activity. (6 marks) Determine the critical path and establish the minimum amount of time complete the entire project without crashing. (4 marks) Which activities have slack, and how much? What paths have slack and how much? (5 marks) Determine the minimum-cost crashing schedule that will reduce the total length of the project by five weeks; which activities should you shorten (crash) and by how much. What is the critical path afte crashing and how much slack does each path have now. (7 marks) (d)