Question 4: a) Comment on the practical difficulty of using PERT technique. (6 marks) b) Comment why AON is commonly used instead of AOA technique when drawing project management network diagram. (4 marks) c) TC Ltd is bidding for a certain project. The PERT based three-way estimates of the duration of the respective task from A to J of this project are given in the table below: Task Preceding Task Duration in days Most Likely 5 Pessimistic 7 A B D E F G H I J A A A B D E CE F G, H, I Optimistic 3 11 6 9 8 7 4 10 8 5 9 12 8 13 8 13 14 6 12 15 8 19 12 16 20 7 i. Draw the project's PERT network and show clearly its critical path. (4 marks) (2 marks) ii. iii. What is the project's normal expected duration? What is the probability if the project can be completed in 52 days? (4 marks)