Critical Path Analysis Topic Review summary

Key learning points

• Draw activity-on-arc (or on-node) networks carefully with dummies if needed.
• Forward pass → earliest event/activity times; backward pass → latest times.
• Total float $= \text{latest finish} - \text{earliest start} - \text{duration}$.
• Critical activities have zero float; the critical path determines project duration.
• Gantt charts and resource histograms appear in scheduling follow-ups.

Worked example 1 — Float

Activity duration 4, EST 3, LFT 10. Float?

Working

Total float formula.

Worked example 2 — Critical

Why is zero float critical?

Working

Lies on a longest path.

Worked example 3 — Practice point 1

Apply this idea from the Topic Review: Draw activity-on-arc (or on-node) networks carefully with dummies if needed.

Working

Attempt without notes, then check the answers PDF.

Worked example 4 — Practice point 2

Apply this idea from the Topic Review: Forward pass → earliest event/activity times; backward pass → latest times.

Working

Attempt without notes, then check the answers PDF.

Scaffolded Learning Sheet and answers (PDFs)

This page is a short, searchable overview for revision and search engines. Use the Scaffolded Learning Sheet first, then the Answers PDF for a full written solution. The printable PDFs remain the main classroom resource.