The objective function to minimize is:
z=30x−30y+1800
Subject to constraints:
- x+y≤30
- x≤15
- y≤20
- x+y≥15
- x,y≥0
The corner points of the feasible region are found by intersecting the constraint lines:
At x=0 and x+y=15:
y=15
Point: (0,15)
At x=0 and y=20:
Point: (0,20)
At y=20 and x+y=30:
x+20=30
x=10
Point: (10,20)
At x=15 and x+y=30:
15+y=30
y=15
Point: (15,15)
At x=15 and x+y=15:
15+y=15
y=0
Point: (15,0)
Evaluating z=30x−30y+1800 at each corner point:
At (0,15):
z=30(0)−30(15)+1800
z=0−450+1800
z=1350
At (0,20):
z=30(0)−30(20)+1800
z=0−600+1800
z=1200
At (10,20):
z=30(10)−30(20)+1800
z=300−600+1800
z=1500
At (15,15):
z=30(15)−30(15)+1800
z=450−450+1800
z=1800
At (15,0):
z=30(15)−30(0)+1800
z=450−0+1800
z=2250
The minimum value is z=1200 at point (0,20).
Therefore, the optimal value is attained at (0,20).