NCERT Example 3 - Linear Programming

Question: Minimise and maximise Z = 3x + 9y subject to x + 3y ≤ 60, x + y ≥ 10, x ≤ y, x ≥ 0, y ≥ 0, graphically.

Answer: Minimum Z = 60 at (5, 5); maximum Z = 180 at every point of the segment joining (15, 15) and (0, 20).

Full step-by-step NCERT solution with diagrams on Something by Zero.