Write the LP formulation for this problem A daily diet must
. Write the LP formulation for this problem
A daily diet must be constructed determining the type and amount of foods to meet certain nutritional requirements at minimum cost. The foods that can be included are tuna fish, milk, spinach and whole-wheat bread; the nutrients we consider are vitamins A, C, and D, and iron. Nutritional and cost data are given in the table below.
Nutrient
Per Gallon of Milk
Per Pound of tuna fish
Per Loaf of bread
Per Pound of spinach
Recommended daily allowance
Vitamin A
6,400 IU
237 IU
0 IU
34,000 IU
5,000 IU
Vitamin C
40 mg
0 mg
0 mg
71 mg
75 mg
Vitamin D
540 IU
0 IU
0 IU
0 IU
400 IU
Iron
28 mg
7 mg
13 mg
8 mg
12 mg
Cost
$1.95
$1.80
$0.75
$0.80
| Nutrient | Per Gallon of Milk | Per Pound of tuna fish | Per Loaf of bread | Per Pound of spinach | Recommended daily allowance |
| Vitamin A | 6,400 IU | 237 IU | 0 IU | 34,000 IU | 5,000 IU |
| Vitamin C | 40 mg | 0 mg | 0 mg | 71 mg | 75 mg |
| Vitamin D | 540 IU | 0 IU | 0 IU | 0 IU | 400 IU |
| Iron | 28 mg | 7 mg | 13 mg | 8 mg | 12 mg |
| Cost | $1.95 | $1.80 | $0.75 | $0.80 |
Solution
Decision variables:
X1: Gallons of Milk
X2: Pounds of tuna fish
X3: Loafs of bread
X4: Pounds of spinach
LP formulation:
Objective function-
Minimise cost, C(X1,X2,X3,X4) = 1.95X1 + 1.80X2 + 0.75X3 + 0.80X4
Subject to constraints-
6400X1 + 237X2 + 0X3 + 3400X4 >= 5000
40X1 + 0X2 + 0X3 + 71X4 >= 75
540X1 + 0X2 + 0X3 + 0X4 >= 400
28X1 + 7X2 + 13X3 + 8X4 >= 12
X1,X2,X3,X4 >= 0

