Maximise Z = 2x1 + 4x2 + x3 + x4
Subject to x1 + 3x2 + x4 ≤ 4
2x1 + x2 ≤ 3
x2 + 4x3 + x4 ≤ 3
x1, x2, x3, x4 ≥ 0
Rewriting in the standard form
Maximise Z = 2x1 + 4x2 + x3 + x4 + 0.S1 + 0.S2 + 0.S3
Subject to x1 + 3x2 + x4 + S1 = 4
2x1 + x2 + S2 = 3
x2 + 4x3 + x4 + S3 = 3
x1, x2, x3, x4, S1, S2, S3 ≥ 0
Solution:
The initial basic solution is x1, x2, x3, x4 = 0, S1 = 4, S2 = 3, S3 = 3
Table 1 depicts the initial table
S1 is the outgoing variable and x2 is the incoming variable to the basic set. The first iteration gives the table 2:
X3 enters the new basic set replacing S3, the second iteration gives the table 3:
X1 enters the new basic set replacing S2, the third iteration gives the table 4:
Since all the elements of the last row are non-negative, the optimal solution is Z = 13/2, which is achieved for x2 = 1, x1 = 1,
x3 = 1/2, and x4 = 0.