NZ Level 8 (NZC) Level 3 (NCEA) [In development]

Applications of Critical Paths

In order to insert a window, several activities need to be performed to complete the project. The following table displays the projectâ€™s activities and their descriptions, dependencies, and durations.

Activity | Description | Dependencies | Duration (hours) |
---|---|---|---|

$A$A |
Buy handtools | - | $2$2 |

$B$B |
Buy raw material | - | $4$4 |

$C$C |
Cut a hole in the wall | $A$A |
$3$3 |

$D$D |
Mix up cement | $B$B |
$2$2 |

$E$E |
Lay thin film of cement on the hole's borders. | $C,D$C,D |
$3$3 |

$F$F |
Insert window frame | $E$E |
$1$1 |

$G$G |
Insert window | $F$F |
$1$1 |

$H$H |
Insert sealant and clean smudges. | $G$G |
$2$2 |

a

Which network correctly represents the information in the activity table?

A

B

C

D

A

B

C

D

b

Find the earliest starting time (EST) for each vertex.

Vertex | Start | 1 | 2 | 3 | 4 | 5 | 6 | Finish |
---|---|---|---|---|---|---|---|---|

EST | $\editable{}$ | $\editable{}$ | $\editable{}$ | $\editable{}$ | $\editable{}$ | $\editable{}$ | $\editable{}$ | $\editable{}$ |

c

Now find the latest starting time (LST) for each vertex.

Vertex | Start | 1 | 2 | 3 | 4 | 5 | 6 | Finish |
---|---|---|---|---|---|---|---|---|

EST | $0$0 | $2$2 | $4$4 | $6$6 | $9$9 | $10$10 | $11$11 | $13$13 |

LST | $\editable{}$ | $\editable{}$ | $\editable{}$ | $\editable{}$ | $\editable{}$ | $\editable{}$ | $\editable{}$ | $\editable{}$ |

d

Determine a critical path through the network by listing the activities in order.

Write all activities on the same line, separated by commas

e

What is the duration of the critical path?

f

If the sealant arrived one hour after that activity's earliest start time, how would that affect the project finish time?

There would be no effect on the finish time for the project.

A

The project would be delayed by one hour.

B

The project would finish one hour earlier.

C

There would be no effect on the finish time for the project.

A

The project would be delayed by one hour.

B

The project would finish one hour earlier.

C

Easy

Approx 5 minutes

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