Deck 9: Project Scheduling: Pertcpm

Question 1

The earliest start time rule

A)compares the starting times of all activities for successors of an activity.
B)compares the finish times for all immediate predecessors of an activity.
C)determines when the project can begin.
D)determines when the project must begin.

Answer 1

B

Question 2

Slack equals

A)LF - EF.
B)EF - LF.
C)EF - LS.
D)LF - ES.

Answer 2

EF - LF.

Question 3

Activities K, M and S immediately follow activity H, and their latest start times are 14, 18, and 11. The latest finish time for activity H

A)is 11.
B)is 14.
C)is 18.
D)cannot be determined.

Answer 3

A

Question 4

Arcs in a project network indicate

A)completion times.
B)precedence relationships.
C)activities.
D)the critical path.

Question 5

A path through a project network must reach every node.

Question 6

Which is not a significant challenge of project scheduling?

A)deadlines exist.
B)activities are independent.
C)many employees could be required.
D)delays are costly.

Question 7

The critical path

A)is any path that goes from the starting node to the completion node.
B)is a combination of all paths.
C)is the shortest path.
D)is the longest path.

Question 8

PERT and CPM are applicable only when there is no dependence among activities.

Question 9

When activity times are uncertain,

A)assume they are normally distributed.
B)calculate the expected time, using (a + 4m + b)/6.
C)use the most likely time.
D)calculate the expected time, using (a + m + b)/3.

Question 10

Activities with zero slack

A)can be delayed.
B)must be completed first.
C)lie on a critical path.
D)have no predecessors.

Question 11

Critical activities are those that can be delayed without delaying the entire project.

Question 12

Activities following a node

A)can begin as soon as any activity preceding the node has been completed.
B)have an earliest start time equal to the largest of the earliest finish times for all activities entering the node.
C)have a latest start time equal to the largest of the earliest finish times for all activities entering the node.
D)None of the alternatives is correct.

Question 13

Activities G, P, and R are the immediate predecessors for activity W. If the earliest finish times for the three are 12, 15, and 10, then the earliest start time for W

A)is 10.
B)is 12.
C)is 15.
D)cannot be determined.

Question 14

To determine how to crash activity times

A)normal activity costs and costs under maximum crashing must be known.
B)shortest times with crashing must be known.
C)realize that new paths may become critical.
D)All of the alternatives are true.

Question 15

For an activity with more than one immediate successor activity, its latest-finish time is equal to the

A)largest latest-finish time among its immediate successors.
B)smallest latest-finish time among its immediate successors.
C)largest latest-start time among its immediate successors.
D)smallest latest-start time among its immediate successors.

Question 16

For an activity with more than one immediate predecessor activity, which of the following is used to compute its earliest finish (EF) time?

A)the largest EF among the immediate predecessors.
B)the average EF among the immediate predecessors.
C)the largest LF among the immediate predecessors.
D)the difference in EF among the immediate predecessors.

Question 17

In deciding which activities to crash, one must

A)crash all critical activities.
B)crash largest-duration activities.
C)crash lowest-cost activities.
D)crash activities on the critical path(s) only.

Question 18

Which of the following is always true about a critical activity?

A)LS = EF.
B)LF = LS.
C)ES = LS.
D)EF = ES.

Question 19

PERT and CPM

A)are most valuable when a small number of activities must be scheduled.
B)have different features and are not applied to the same situation.
C)do not require a chronological relationship among activities.
D)have been combined to develop a procedure that uses the best of each.

Question 20

Which of the following is a general rule for crashing activities?

A)Crash only non-critical activities.
B)Crash activities with zero slack.
C)Crash activities with the greatest number of predecessors.
D)Crash the path with the fewest activities.

Question 21

Crashing refers to an unanticipated delay in a critical path activity that causes the total time to exceed its limit.

Question 22

The project manager should monitor the progress of any activity with a large time variance even if the expected time does not identify the activity as a critical activity.

Question 23

Name at least three managerial situations where answers are provided by project management solutions.

Question 24

Why should projects be monitored after the critical path is found?

Question 25

The length of time an activity can be delayed without affecting the project completion time is the slack.

Question 26

Once the earliest and latest times are calculated, how is the critical path determined?

Question 27

The latest finish time for an activity is the largest of the latest start times for all activities that immediately follow the activity.

Question 28

Explain how and why all predecessor activities must be considered when finding the earliest start time.

Question 29

A critical activity can be part of a noncritical path.

Question 30

A project network is shown below. Use a forward and a backward pass to determine the critical path, and then fill out the table below. Now assume that the times listed are only the expected times instead of being fixed times. Is the probability of being finished in more than 28 weeks more or less than 50%?

Question 31

The earliest finish time for the final activity is the project duration.

Question 32

Constraints in the LP models for crashing decisions are required to compare the activity's earliest finish time with the earliest finish time of each predecessor.

Question 33

When activity times are uncertain, total project time is normally distributed with mean equal to the sum of the means of all of the critical activities.

Question 34

The variance in the project completion time is the sum of the variances of all activities in the project.

Question 35

When activity times are uncertain, an activity's most likely time is the same as its expected time.

Question 36

A project network is shown below. Use a forward and a backward pass to determine the critical path, and then fill out the table below. Now assume that the times listed are only the expected times instead of being fixed times. Is the probability of being finished in fewer than 25 weeks more or less than 50%?

Question 37

The earliest start time for an activity is equal to the smallest of the earliest finish times for all its immediate predecessors.

Question 38

The linear programming model for crashing presented in the textbook assumes that any portion of the activity crash time can be achieved for a corresponding portion of the activity crashing cost.

Question 39

From this schedule of activities, draw the PERT/CPM network.

Question 40

Explain how and why all successor activities must be considered when finding the latest finish time.

Question 41

Given the following network with activities and times estimated in days, $$\begin{array}{l}\text { Most }\\\begin{array} { c c c c } \text { Activity } & \text { Optimistic } & \text { Probable } & \text { Pessimistic } \\\hline \text { A } & 2 & 5 & 6 \\\text { B } & 1 & 3 & 7 \\\text { C } & 6 & 7 & 10 \\\text { D } & 5 & 12 & 14 \\\text { E } & 3 & 4 & 5 \\\text { F } & 8 & 9 & 12 \\\text { G } & 4 & 6 & 8 \\\text { H } & 3 & 6 & 8 \\\text { I } & 5 & 7 & 12 \\\text { J } & 12 & 13 & 14 \\\text { K } & 1 & 3 & 4\end{array}\end{array}$$
a.What are the critical path activities?
b.What is the expected time to complete the project?
c.What is the probability the project will take more than 28 days to complete?

Question 42

Use the following network of related activities with their duration times to complete a row for each activity under the column headings below.

Question 43

Use the following network of related activities with their duration times to complete a row for each activity under the column headings below.

Question 44

The critical path for this network is A - E - F and the project completion time is 22 weeks. $$\begin{array} { c c c c r } \text { Activity } & \begin{array} { c } \text { Normal } \\\text { Time }\end{array} & \begin{array} { c } \text { Crash } \\\text { Time }\end{array} & \begin{array} { c } \text { Normal } \\\text { Cost }\end{array} & { \begin{array} { c } \text { Crash } \\\text { Cost }\end{array} } \\\hline \text { A } & 12 & 8 & 8,000 & 12,000 \\\text { B } & 14 & 10 & 5,000 & 7,500 \\\text { C } & 8 & 8 & 10,000 & 10,000 \\\text { D } & 5 & 3 & 6,000 & 8,000 \\\text { E } & 4 & 3 & 5,000 & 7,000 \\\text { F } & 6 & 5 & 9,000 & 12,000 \\\text { G } & 10 & 8 & 5,000 & 8,000\end{array}$$ If a deadline of 17 weeks is imposed, give the linear programming model for the crashing decision.