3D.4.4 Total float and Gantt charts Quiz: Pearson Edexcel Further Maths, Unit 38

The 20 questions

1. Total float F(i,j) of an activity (i,j) is defined as

   • e_j - l_i + duration(i,j)
   • e_i - l_j - duration(i,j)
   • l_j - e_i - duration(i,j)
   • l_j - e_j - duration(i,j)

2. Total float of an activity is

   • the time between its start and finish only
   • the amount it can be delayed without delaying project completion
   • the time its workers spend idle
   • the sum of the floats along the whole path

3. A Gantt chart shows

   • the workers' pay for each activity
   • the net profit of the project
   • each activity as a bar on a time axis, with its start and duration
   • only the precedence table

4. On a cascade Gantt chart, an activity with total float is drawn

   • as a single point at its latest finish
   • as a bar starting at its latest start only
   • only if it is on the critical path
   • as its earliest-start bar, with a line showing the float after it

5. A cascade chart is another name for a

   • Venn diagram
   • histogram
   • precedence table
   • Gantt chart

6. The earliest start of activity (i,j) is

   • e_j, the earliest time of event j
   • l_i, the latest time of event i
   • e_i, the earliest time of event i
   • l_j, the latest time of event j

7. The latest finish of activity (i,j) is

   • e_j, the earliest time of event j
   • l_i + duration(i,j)
   • l_j, the latest time of event j
   • e_i, the earliest time of event i

8. An activity has earliest start e_i = 4, latest finish l_j = 12 and duration 5. What is its total float?

   • 5
   • 12
   • 3
   • 8

9. An activity has earliest start e_i = 0, latest finish l_j = 6 and duration 6. What is its total float?

   • 12
   • 0
   • 6
   • -6

10. An activity has e_i = 2, l_j = 7 and duration 3. What is its total float?

    • 7
    • 2
    • 4
    • -2

11. An activity starts at its earliest time 3, lasts 4 and has total float 2. What is its latest finish?

    • 11
    • 7
    • 5
    • 9

12. An activity has total float 5 and lasts 3 days. It is delayed by 4 days. What happens to the project completion?

    • No change
    • Project delayed by 4
    • Project delayed by 9
    • Project delayed by 1

13. An activity has earliest start 5, duration 3 and total float 4. What is its latest start?

    • 8
    • 12
    • 7
    • 9

14. An activity has e_i = 8, l_i = 10, duration 3, e_j = 11 and l_j = 12. What is its total float?

    • 0
    • 3
    • 1
    • 4

15. An activity Y starts at its earliest time 4, lasts 10 and has total float 6. What is its latest finish?

    • 16
    • 20
    • 24
    • 14

16. Why can total float be shared between activities on the same path?

    • a delay on one float-carrying activity uses up float shared with later activities on that path
    • floats are only defined for critical paths
    • each activity has private float only
    • floats always add up

17. An activity has duration 6, earliest start 2, and its head event has latest time 9. What is its latest start?

    • 9
    • 2
    • 3
    • 1

18. Activities A (time 0 to 3), B (time 1 to 5) and C (time 3 to 6) are drawn on a Gantt chart. How many are active at time 2?

    • 3
    • 1
    • 0
    • 2

19. Why does delaying a critical activity delay the project, while delaying within its float does not?

    • a critical activity has no float, so any delay pushes the finish back, whereas a delay within float only uses slack
    • critical activities have longer durations than others
    • float is always shared between all activities
    • delays only matter when workers are idle

20. An activity has earliest start 3, duration 4 and latest head event time 10. What is its total float, and is it critical?

    • 3 units, not critical
    • 3 units, critical
    • 0 units, critical
    • 7 units, not critical

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