Project Test Bank is composed of activities we will refer to as A, B, C, and D for convenience (and lack of creativity). Durations and precedence requirements are shown in the table. Each of these activities can be conveniently laddered into two sub-activities of equal duration, so activity C in the original project becomes two activities, C1 and C2, each of which last 7 days. The first half of each activity serves as the predecessor to its second half and the first half of the original following activity. What is difference in the late start time for activity C in the original project and activity C1 in the laddered project?
A) 3
B) 5
C) 7
D) 9

Question

Project Test Bank is composed of activities we will refer to as A, B, C, and D for convenience (and lack of creativity). Durations and precedence requirements are shown in the table. Each of these activities can be conveniently laddered into two sub-activities of equal duration, so activity C in the original project becomes two activities, C1 and C2, each of which last 7 days. The first half of each activity serves as the predecessor to its second half and the first half of the original following activity. What is difference in the late start time for activity C in the original project and activity C1 in the laddered project? 
A) 3 
B) 5 
C) 7 
D) 9

Quizplus · Accepted Answer

In the original project, activity C has a duration of 14 days and is preceded by activity B, which has a duration of 5 days. Therefore, the early start time for activity C is Day 6 (after the completion of activity B on Day 5). The late start time for activity C is Day 9 (calculated as the late finish time for activity D minus the duration of activity C).

In the laddered project, activity C is split into two sub-activities, C1 and C2, each with a duration of 7 days. The first half of C1 serves as the predecessor to the second half of C1 and the first half of C2, as well as the first half of activity D. Therefore, the early start time for C1 is Day 6 (after the completion of activity B on Day 5). The late start time for C1 is Day 2 (calculated as the late finish time for C2 minus the duration of C1).

The difference between the late start time for activity C in the original project and activity C1 in the laddered project is 7 (9 - 2). Therefore, the correct answer is (C) 7.

Project Test Bank Is Composed of Activities We Will Refer