Subjects · Leaving Cert Applied Maths
Leaving Cert Applied Maths: Project scheduling & critical path
How often Project scheduling & critical path comes up on the Applied Maths papers, every year it was asked, and questions to try.
HL Asked on 2 of the last 3 Higher Level papers, most recently in 2024. most years
OL Asked on 2 of the last 3 Ordinary Level papers, most recently in 2024. most years
Quick ones on Project scheduling & critical path.
- The smallest of the incoming totals
- The largest of the incoming totals
- The sum of all incoming durations
- An activity that can be left out of the plan
- The activity with the most float
- A zero-time activity that only shows dependency
- The smallest of the outgoing values
- Its early time plus the float
- The largest of the outgoing values
Show the answers
(a) The largest of the incoming totals
(b) A zero-time activity that only shows dependency
(c) The smallest of the outgoing values
Higher Level
Asked on 2 of the last 3 Higher Level papers, most recently in 2024. most years
Every paper, year by year
| Year | Where it came up |
|---|---|
| 2025 | Not asked |
| 2024 | Q10 |
| 2023 | Q9 |
Links open the State Examinations Commission’s paper for that year.
More Project scheduling & critical path questions
Project scheduling & critical path, 2 marks
In the backward pass, the late time of the final event is set equal to…?
- Zero
- The sum of all activity durations
- Its early time
Show the answer
Its early time
The project should finish as soon as possible, so the finish event's latest allowed time is its earliest time. The backward pass then subtracts durations from there.
Project scheduling & critical path, 2 marks
An activity on the critical path is delayed by 3 days. Effect on the project?
- It finishes 6 days late
- It finishes 3 days late
- It is not delayed
Show the answer
It finishes 3 days late
Critical activities have zero float, so any delay passes straight through to the end of the project, day for day.
Project scheduling & critical path, 2 marks
An event has early time 10 and late time 13. Is it on the critical path?
- No, its early and late times differ
- Yes, every event is on it
- Only if an activity of 3 days leaves it
Show the answer
No, its early and late times differ
Critical events have equal early and late times: there is no slack. Here the event could happen up to 3 time units late without delaying the project.
Ordinary Level
Asked on 2 of the last 3 Ordinary Level papers, most recently in 2024. most years
Every paper, year by year
| Year | Where it came up |
|---|---|
| 2025 | Not asked |
| 2024 | Q9 |
| 2023 | Q10 |
Links open the State Examinations Commission’s paper for that year.
More Project scheduling & critical path questions
Project scheduling & critical path, 3 marks
Activity: start event ET = 5, end event LT = 14, duration 6 hours. Its float?
- 9 hours
- 8 hours
- 3 hours
Show the answer
3 hours
Float = LT(end) − ET(start) − duration = 14 − 5 − 6 = 3 hours. The activity can be delayed up to 3 hours without delaying the project.
Project scheduling & critical path, 2 marks
What is the critical path of a project?
- The path with the most activities
- The longest path through the activity network
- The shortest path through the network
Show the answer
The longest path through the activity network
The project cannot finish until the longest chain of dependent activities is done, so that chain sets the minimum project time. Delaying any of it delays the project.
Project scheduling & critical path, 3 marks
Activity X has a float of 4 days and is delayed by 3 days. Effect on the project?
- No delay to the project
- A 3-day delay to the finish
- A 1-day delay to the finish
Show the answer
No delay to the project
A delay no bigger than the float is absorbed. 3 is less than 4, so the finish date is unchanged, though X now has only 1 day of float left.
Other Applied Maths topics
- Calculus & variable acceleration
- Connected particles & pulleys
- Constant acceleration (suvat)
- Dijkstra's algorithm
- Displacement & velocity graphs
- First-order difference equations
- Forces & Newton's laws
- Friction & inclined planes
- Graphs & network terminology
- Horizontal circular motion
- Loans, savings & finance models
- Matrices & adjacency
- Minimum spanning trees
- Momentum & direct collisions
- Oblique collisions
- Projectile motion
- Recurrence relations & differences
- Reducing second-order DEs
- Resisted motion & drag
- Second-order difference equations
- Separable differential equations
- The modelling cycle & assumptions
- Vectors & the dot product
- Vertical circular motion
- Dimensional analysis
- Dynamic programming & Bellman
- Work, energy & conservation
- Greedy vs dynamic algorithms
- Hooke's law & elastic energy