Critical Path Method Examples 🥇 With Solution

Welcome to PM Calculators, a site dedicated to providing excellent online calculators for business management, including project management. In this post we will use our online critical path method (CPM) calculator and PERT-CPM diagram to develop critical path method examples.

In the following examples, we will perform critical path analysis and CPM network diagrams (Activity-on-node).

We have taken the critical path method problems from the major operations management books used in university teaching as

  1. Krajewski, L. J., Malhotra, M. K., & Ritzman, L. P. (2015). Operations Management: Processes and Supply Chains, Student Value Edition (11th Edition) (11th ed.). Pearson.
  2. Heizer, J., & Render, B. (2013). Operations Management (11th Edition) (11th ed.). Pearson.
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Example 2: Kids and Tots Apparel

The following information is known about a project to upgrade a point-of-sale system at Kids and Tots Apparel.

Activity Activity Time (days) Immediate Predecessor(s)
A 8
B 4 A
C 3 A
D 5 B,C
E 4 D
F 2 E
G 8 E
  1. Draw a network diagram for this project.
  2. Determine the critical path and project duration.
  3. Calculate the slack for each activity.

Solution

a. The network diagram is:

network diagram

The activity diagram in nodes with all time and float calculations is:

activity diagram in nodes

b. The results of the project are:

The critical path is:
A → B → D → E → G


The total project time is: 29 days

c. The following table shows the results for each activity:

Activity Time Early Start (ES) Early Finish (EF) Late Start (LS) Late Finish (LF) Slack (S)
A 4 0 4 0 4 0
B 5 4 9 4 9 0
C 4 4 8 5 9 1
D 4 9 13 13 17 4
E 1 9 10 16 17 7
F 6 9 15 9 15 0
G 3 13 16 17 20 4
H 2 15 17 18 20 3
I 5 15 20 15 20 0
J 7 20 27 20 27 0

We got the example from Krajewski’s book (1) Chapter 7, Problem 2.

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Example 2: Kids and Tots Apparel