# Construction Planning and Management MCQs -7| Civil Engineering MCQs | Competitive Exams 1. In time-cost optimization of a project, crashing is done _____.
[A] on all the activities
[B] on original critical activities and those that become critical at any stage of crashing in order of  ascending cost slope
[C] on all activities lying on the original critical path
[D] only on activities lying on original critical path and having flatter cost slopes

2. Figure below shows the network for a particular project which consists of four activities Normal Time and Crash Time for each activity are given below:

 Activity Normal Time (days) Crash Time (days) 1-2 3 2 2-3 4 2 2-4 5 4 3-4 7 5

The minimum time required for the completion of project is _____.
[A] 9 days
[B] 13 days
[C] 14 days
[D] 19 days

3. The optimistic, most likely and pessimistic time estimates of an activity are 5, 10, 21 days. What is the expected time and standard deviation?
[A] 12, 3
[B] 11,4
[C] 11, 2.67
[D] 10, 16

Solution:

to = 5 days, tm = 10 days, tp = 21days
Expected time, te = (to + 4 tm + tp)/6
= (5 + 4×10 + 21)/6
= 11 days
Standard deviation σ = (tp – to)/6
= (21-5)/6
σ = 2.67 days

4. Slack is given as the difference between _____.

[A] Latest allowable occurrence time and earliest expected time
[B] Latest allowable time and pessimistic time estimate
[C] Earliest expected time and latest
[D] Final event time and initial event time allowable time

5. If the probability factor is zero, the chances of completing the project in scheduled time are ______.
[A] 0%
[B] 50%
[C] 75%
[D] 100%