OCR Further Discrete AS 2020 November — Question 4

Exam BoardOCR
ModuleFurther Discrete AS (Further Discrete AS)
Year2020
SessionNovember
TopicPermutations & Arrangements
TypeAssignment/allocation matching problems

4 Bob is extending his attic with the help of some friends, including his architect friend Archie. The activities involved, their durations (in days) and Bob's notes are given below.
ActivityDuration (days)Notes
AArchie takes measurements1
BArchie draws up plans3Must come after A
CPlans are approved21Must come after B
DBob orders materials2Must come after B
EMaterials delivered10Must come after D
FWork area cleared5Must come after A
GPlumbing and electrics3Must come after C, E and F
HFloors, walls and ceilings24Must come after G
IStaircase2Must come after H
JWindows1Must come after H
KDecorating6Must come after I and J
Archie has started to construct an activity network to represent the project.
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  1. Complete the activity network in the Printed Answer Booklet and use it to determine
    • the minimum completion time
    • the critical activities
      for the project.
    • Give two different reasons why the project might take longer than the minimum completion time.
    • For the activity with the longest float
    • calculate this float, in days
    • interpret this float in context.