Iso-contribution line
An iso-contribution line joins product combinations yielding the same total contribution for a linear objective. Parallel lines represent different values of that objective. In a graphical maximisation, move the line towards higher contribution until the last feasible point or edge is reached. An iso-profit line has the same slope when fixed cost is constant, but the contribution and final-profit labels should remain clear.
Worked example
With Z = 4x + 6y, combinations (3,0) and (0,2) both give contribution 12 and lie on the same iso-contribution line.
Common mistake
The highest mathematical line is useful only where it still touches the feasible region; a line outside the constraints is not an attainable result.
Where it appears in your exams
| Qualification | Exam | Relationship | Period |
|---|---|---|---|
| ACCA | PM | Direct | September 2026–June 2027 |