40. An engineering firm is tendering for a contract to supply a steel fabrication with a target duration of 60 days. The tasks have been analysed as follows:

(a) You are required to calculate the expected project duration and identify the critical path.
The firm is awarded the contract and starts work with all activities commencing on their earliest start times but after work on 23rd day there is a fire which destroys all the work done on task C and the work-in-progress on tasks G and H. Fortunately, no other completed tasks are affected but it is estimated that task M will now need 15 days. The project manager thinks that after the fire there will be variability in the task times and has made some uncertainty estimates which are shown as task standard deviations in days:

You are required

(b) to calculate the new expected duration and the critical path through the remaining activities after the fire;
(

c) to calculate the probability of the project being completed on time after the fire.

Transcribed Image Text:

Task Immediate Predecessors Duration (Days) ABCDEFG 10 12 A 10 A 9 A 13 A, B 17 C 12 H 1 K C, D E G, H 12 10 14 13 H L H, 1 14 M H, I, F 13