In: Operations Management
A developer that specializes in compact urban amusement parks has formulated the following list of activities necessary to release a contract for the preparation of a new site. Times are given in weeks.
Estimated Immediate Activity Time
Activity Description Predecessors (weeks)
A Preliminary architectural design _ 14
B Community impact hearings A 2
C Line up potential financiers A 12
D Permit application A 5
E Negotiate com’ity impact details B 6
F Final Design B 8
G Loan approval C, F 3
H Permit hearings D 2
I Permit granting H 8
J Negotiate contract G, I 6
K Release contract E, J 3
Which activities are on the critical path
Based on the given data, we prepare a project network diagram as shown below:
The above network diagram in the form of formulas is shown below for better understanding and reference:
The above project diagram is prepared as per the legend shown in the top-left corner.
EST = Early start time
LST = Late start time
EFT = Early finish time
LFT = Late finish time
SLK = Slack = LST - EST or Slack = LFT - EFT
The EST of an activity = EFT of previous activity
EFT of an activity = EST + Duration
Similarly, LFT & LST are calculated during the backward pass.
There are multiple paths in the diagram:
A-B-E-K
A-B-F-G-J-K
A-C-G-J-K
A-D-H-I-J-K
Out of the above paths, path A-C-G-J-K and A-D-H-I-J-K are the longest paths and have 0 slack for all activities on the path. Hence, these paths are the critical paths.
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