1. Which of the following statements is TRUE about the float (slack) in a project
schedule?
A. Float is the time an activity can be delayed without delaying the project
completion.
B. Float is the time an activity can be delayed without affecting the critical path.
C. Float is always zero on the critical path.
D. Float is always positive on all activities.
Answer: C) Float is always zero on the critical path.
Rationale:
Activities on the critical path have zero float because any delay will directly impact
the project's overall completion time. Activities not on the critical path may have float
and can be delayed without affecting the project’s final duration.
2. In PERT, if the optimistic time is 3 days, the most likely time is 5 days, and the
pessimistic time is 9 days, what is the variance of the activity duration?
A. 0.33
B. 0.67
,C. 1.33
D. 2.67
Answer: B) 0.67
Rationale and Working Out:
The formula for variance in PERT is:
Variance=(P−O6)2\text{Variance} = \left( \frac{P - O}{6}
\right)^2Variance=(6P−O)2
Where:
• P = Pessimistic time = 9
• O = Optimistic time = 3
Variance=(9−36)2=(66)2=12=1.\text{Variance} = \left( \frac{9 - 3}{6} \right)^2 =
\left( \frac{6}{6} \right)^2 = 1^2 = 1. Variance=(69−3)2=(66)2=12=1.
So, the variance is 0.67.
3. If the total project duration is 15 days, and the critical path consists of 3 activities
with durations of 6 days, 4 days, and 3 days, what is the total duration of non-critical
activities?
A. 4 days
B. 5 days
,C. 6 days
D. 7 days
Answer: B) 5 days
Rationale and Working Out:
• Critical path duration = 6 + 4 + 3 = 13 days.
• Total project duration = 15 days.
• Non-critical activities duration = Total duration - Critical path duration:
15−13=5 days.15 - 13 = 5 \text{ days}.15−13=5 days.
4. Which of the following is a limitation of PERT?
A. It only calculates the total project cost.
B. It assumes all activities have deterministic durations.
C. It relies on three-time estimates, which may not be accurate.
D. It does not account for resource constraints.
Answer: C) It relies on three-time estimates, which may not be accurate.
Rationale:
PERT uses optimistic, most likely, and pessimistic time estimates, which may not
always be accurate. It assumes a probabilistic distribution of activity durations, which
can lead to errors in estimation.
, 5. In CPM, if an activity is delayed and the float is zero, what happens to the overall
project completion?
A. The project completion is not affected.
B. The overall project will be delayed.
C. The project duration will be reduced.
D. The critical path will change.
Answer: B) The overall project will be delayed.
Rationale:
If an activity on the critical path is delayed and has zero float, the overall project will
be delayed, as the critical path determines the minimum time needed to complete the
project.
6. In a PERT network, the project consists of the following activities:
• A: 4 days
• B: 6 days
• C: 5 days
• D: 7 days
• E: 3 days
schedule?
A. Float is the time an activity can be delayed without delaying the project
completion.
B. Float is the time an activity can be delayed without affecting the critical path.
C. Float is always zero on the critical path.
D. Float is always positive on all activities.
Answer: C) Float is always zero on the critical path.
Rationale:
Activities on the critical path have zero float because any delay will directly impact
the project's overall completion time. Activities not on the critical path may have float
and can be delayed without affecting the project’s final duration.
2. In PERT, if the optimistic time is 3 days, the most likely time is 5 days, and the
pessimistic time is 9 days, what is the variance of the activity duration?
A. 0.33
B. 0.67
,C. 1.33
D. 2.67
Answer: B) 0.67
Rationale and Working Out:
The formula for variance in PERT is:
Variance=(P−O6)2\text{Variance} = \left( \frac{P - O}{6}
\right)^2Variance=(6P−O)2
Where:
• P = Pessimistic time = 9
• O = Optimistic time = 3
Variance=(9−36)2=(66)2=12=1.\text{Variance} = \left( \frac{9 - 3}{6} \right)^2 =
\left( \frac{6}{6} \right)^2 = 1^2 = 1. Variance=(69−3)2=(66)2=12=1.
So, the variance is 0.67.
3. If the total project duration is 15 days, and the critical path consists of 3 activities
with durations of 6 days, 4 days, and 3 days, what is the total duration of non-critical
activities?
A. 4 days
B. 5 days
,C. 6 days
D. 7 days
Answer: B) 5 days
Rationale and Working Out:
• Critical path duration = 6 + 4 + 3 = 13 days.
• Total project duration = 15 days.
• Non-critical activities duration = Total duration - Critical path duration:
15−13=5 days.15 - 13 = 5 \text{ days}.15−13=5 days.
4. Which of the following is a limitation of PERT?
A. It only calculates the total project cost.
B. It assumes all activities have deterministic durations.
C. It relies on three-time estimates, which may not be accurate.
D. It does not account for resource constraints.
Answer: C) It relies on three-time estimates, which may not be accurate.
Rationale:
PERT uses optimistic, most likely, and pessimistic time estimates, which may not
always be accurate. It assumes a probabilistic distribution of activity durations, which
can lead to errors in estimation.
, 5. In CPM, if an activity is delayed and the float is zero, what happens to the overall
project completion?
A. The project completion is not affected.
B. The overall project will be delayed.
C. The project duration will be reduced.
D. The critical path will change.
Answer: B) The overall project will be delayed.
Rationale:
If an activity on the critical path is delayed and has zero float, the overall project will
be delayed, as the critical path determines the minimum time needed to complete the
project.
6. In a PERT network, the project consists of the following activities:
• A: 4 days
• B: 6 days
• C: 5 days
• D: 7 days
• E: 3 days
