Pert Mustang
Chapter 2 Homework Problem Solutions Chapter 2 Project Management Study Objectives: construct a network diagram for a project determine critical path and expected completion time of a project with deterministic task times (note: some of us also do calculations for probabilistic times, but not required) calculate slack times for a particular task know how to “crash” a project down to a certain completion time at the lowest cost (note: just the concept of crashing needs to be discussed and not the calculations; some of us do the calculations, others do not)
Discussion Questions:
3. Most everyone should be able to describe some project they have been a part of. Common ones include preparing a high-school yearbook, planning a major party, building a new home, and organizing a banquet for a club or student group. Take time to elicit examples of activities and their interrelatedness. Press the students for the reasons behind their rating of the project manager. If the student is the project manager, ask the student what s/he thinks are positive attributes for a project manager in such an example. Problem 1 (page 79): Given: Activity precedence relationship and activity times To do: a. draw the network diagram b. Calculate the critical path for this project c. How much slack is in activities G, H, and I? Solution: a. AON network diagram
D 2 B 4 Start A 2 C 5 E 1 F 8 G 3 H 5 I 4 J 7 Finish
b. The critical path is A–C–F–H–J with a completion time of 27 days. c.
Activity Duration A 2 B 4 C 5 D 2 E 1 F 8 G 3 H 5 I 4 J 7
Earliest Start 0 2 2 6 6 7 8 15 15 20
Latest Start 0 3 2 15 16 7 17 15 16 20
Earliest Finish 2 6 7 8 7 15 11 20 19 27
Latest Finish 2 7 7 17 17 15 20 20 20 27
Slack 0 1 0 9 10 0 9 0 1 0
On Critical Path? Yes No Yes No No Yes No Yes No Yes
Problem 2 (page 79): Given: Activity precedence relationship and activity times To do: a. draw the network diagram b. Determine the critical path and project duration c. Calculate the slack
Discussion Questions:
3. Most everyone should be able to describe some project they have been a part of. Common ones include preparing a high-school yearbook, planning a major party, building a new home, and organizing a banquet for a club or student group. Take time to elicit examples of activities and their interrelatedness. Press the students for the reasons behind their rating of the project manager. If the student is the project manager, ask the student what s/he thinks are positive attributes for a project manager in such an example. Problem 1 (page 79): Given: Activity precedence relationship and activity times To do: a. draw the network diagram b. Calculate the critical path for this project c. How much slack is in activities G, H, and I? Solution: a. AON network diagram
D 2 B 4 Start A 2 C 5 E 1 F 8 G 3 H 5 I 4 J 7 Finish
b. The critical path is A–C–F–H–J with a completion time of 27 days. c.
Activity Duration A 2 B 4 C 5 D 2 E 1 F 8 G 3 H 5 I 4 J 7
Earliest Start 0 2 2 6 6 7 8 15 15 20
Latest Start 0 3 2 15 16 7 17 15 16 20
Earliest Finish 2 6 7 8 7 15 11 20 19 27
Latest Finish 2 7 7 17 17 15 20 20 20 27
Slack 0 1 0 9 10 0 9 0 1 0
On Critical Path? Yes No Yes No No Yes No Yes No Yes
Problem 2 (page 79): Given: Activity precedence relationship and activity times To do: a. draw the network diagram b. Determine the critical path and project duration c. Calculate the slack