Computing the Latest Finishing and Starting Times Compute the latest finishing and starting times for the precedence diagram developed in Example 2.

Question

Computing the Latest Finishing and Starting Times
Compute the latest finishing and starting times for the precedence diagram developed in Example 2.

Accepted Answer

We must add the LS and LF times to the brackets on the diagram.

(17.3.1)

Begin by setting the LF time of the last activity equal to the EF of that activity. Thus,
[latex]LF_{5-6}[/latex] = [latex]EF_{5-6}[/latex] = 20 weeks
Obtain the LS time for activity 5-6 by subtracting the activity time, t, from the LF time:
[latex]LS_{5-6}[/latex] = [latex]LF_{5-6}[/latex] − t = 20 − 1 = 19
Mark these values on the diagram:

(17.3.2)

The LS time of 19 for activity 5-6 now becomes the LF time for each of the activities that precedes activity 5-6. This permits determination of the LS times for each of those activities: Subtract the activity time from the LF to obtain the LS time for the activity. The LS time for activity 3-5 is 19 − 9 = 10.

(17.3.3)

Next, the LS for activity 4-5, which is 16, becomes the LF for activity 2-4, and the LS for activity 3-5, which is 10, becomes the LF for activity 1-3. Using these values, you find the LS for each of these activities by subtracting the activity time from the LF time.

(17.3.4)

The LF for activity 1-2 is the smaller of the two LS times of the activities that 1-2 precedes.
Hence, the LF time for activity 1-2 is 8. The reason you use the smaller time is that activity 1-2 must finish at a time that permits all following activities to start no later than their LS times.
Once you have determined the LF time of activity 1-2, find its LS time by subtracting the activity time of 8 from the LF time of 8. Hence, the LS time is 0.

(17.3.5)

Question 17.3: Computing the Latest Finishing and Starting Times Compute th...

Related Answered Questions

Verified Answer:

Expected times in weeks, as well as variances, for the major activities of an R&D project are depicted in the following table. Determine the probability that project completion time will be: a. 50 weeks or less b. More than 50 weeks ...

Verified Answer:

Verified Answer:

Costs for a project are $12,000 per week for as long as the project lasts. The project manager has supplied the cost and time information shown. Use the information to: a. Determine an optimum crashing plan. b. Graph the total costs for the plan. ...

Verified Answer:

Using the computing algorithm, determine the slack times for the following AOA diagram. Identify the activities on the critical path. ...

Verified Answer:

A path in a network has three activities. Their standard deviations are 1.50, 0.80, and 1.30. Find the path standard deviation. ...

Verified Answer:

The following table contains information related to the major activities of a research project. Use the information to do the following: a. Draw a precedence diagram using AOA. b. Find the critical path. c. Determine the expected length of the project. ...

Verified Answer:

Optimal Project Crashing Using the following information, develop the optimal time–cost solution. Project costs are $1,000 per day. ...

Verified Answer:

Computing Slack Times Compute slack times for the preceding example. ...

Verified Answer:

Computing Earliest Starting and Finishing Times Compute the earliest starting time and earliest finishing time for each activity in the diagram shown in Figure 17.5. ...

Verified Answer: