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Networks, STD2 EQ-Bank 2 MC

The Gantt chart below shows the activities involved in organising a school sports carnival. 
  

   
Which activity has the greatest float time?

  1. \(\text{B}\)
  2. \(\text{D}\)
  3. \(\text{E}\)
  4. \(\text{G}\)
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\(B\)

Show Worked Solution

\(\text{From the Gantt chart, the dashed extensions show:}\)

\(\text{B: float = 3 hours}\)

\(\text{D: float = 5 hours}\)

\(\text{E: float = 3 hours}\)

\(\text{G: float = 0 (critical path, no dashed extension)}\)

\(\text{Activity D has the greatest float time (5 hours).}\)

\(\Rightarrow B\)

Networks, STD2 EQ-Bank 6 MC

The Gantt chart below shows the activities involved in organising a community market day. Critical path activities are shown as solid bars and non-critical activities show available float as dashed extensions.
  


  

Activity \(D\) is delayed by 7 hours and activity \(B\) is delayed by 1 hour. What is the new minimum completion time for the project?

  1. 14 hours
  2. 15 hours
  3. 16 hours
  4. 22 hours
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\(C\)

Show Worked Solution

\(\text{From the Gantt chart:}\)

\(\text{D has float of 5 hours. Delay of 7 exceeds float by 2.}\)

\(\text{B has float of 3 hours. Delay of 1 is within float.}\)

\(\text{Only the delay to D affects completion time.}\)

\(\text{New minimum} = 14+2 = 16 \text{ hours}\)

\(\Rightarrow C\)

Networks, STD2 EQ-Bank 25

The construction of a new reptile exhibit is a project involving nine activities, \(A\) to \(I\). The network diagram below shows the activities and their completion times in weeks. Some values are missing.

The Gantt chart below has been created for this project.
  


  
  1. Using the Gantt chart, identify the critical path.   (1 mark)
  2. Use the Gantt chart to determine the missing values in the network diagram.   (2 marks)
  3. Activity \(E\) is delayed by 8 weeks. Using the Gantt chart, explain whether this will affect the minimum completion time of the project.   (2 marks)
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a.    \(ACDFGI\)

b.    \(\text{B} = 5 \text{ weeks, H} = 7 \text{ weeks}\)

c.    \(\text{From the Gantt chart, activity E has a float of 6 weeks (see the dashed}\)

\(\text{extension from week 10 to 16).}\)

\(\text{The delay of 8 weeks exceeds the float of 6 weeks.}\)

\(\text{The project will be delayed by } 8-6 = 2 \text{ weeks.}\)

\(\text{New minimum completion time} = 25+2 = 27 \text{ weeks.}\)

Show Worked Solution

a.    \(\text{The critical path is the continuous solid bar on row 1 of the Gantt chart.}\)

\(\text{Critical path:}\ ACDFGI\)
 

b.    \(\text{Activities B and H are not labelled in the network diagram.}\)

\(\text{From the Gantt chart:}\)

\(\text{B starts at week 0, ends at week 5} \to \text{duration} = 5 \text{ weeks}\)

\(\text{H starts at week 7, ends at week 14} \to \text{duration} = 7 \text{ weeks}\)
 

c.    \(\text{From the Gantt chart, activity E has a float of 6 weeks (see the dashed}\)

\(\text{extension from week 10 to 16).}\)

\(\text{The delay of 8 weeks exceeds the float of 6 weeks.}\)

\(\text{The project will be delayed by } 8-6 = 2 \text{ weeks.}\)

\(\text{New minimum completion time} = 25+2 = 27 \text{ weeks.}\)