Below is a project with the activities composing it. Optimistic 5 8 Activity A B D E F G H I Successors H E F End G End I End ala TIME IN DAYS Most Likely 6 8 8 12 6 6 3 4 7 Pessimistic 7 11 11 15 9 7 7 5 8 L92 5 5 2 4 5 (a) Construct the network and find the expected completion time of the project. (10 marks) (b) What is the probability that the project can be completed in 24 days or less? And what is the probability in 21 days or less? (5 marks) (c) Suppose it is now the end of the seventh day and that activities A and B have been completed while activity D is 50% completed. Time estimates for the completion of the remaining of activity D are 5, 6 and 7. Activities C and H are ready to begin. Determine the probability of finishing the project by day 24 and the probability of finishing by day 21 respectively