Hello world,
Can anyone please help me solve this Integer programming question. I have tried to solve it myself, yet when I try executing and runing it on "Xpress Mosel" it just doesnt work!!


ABC has deliveries to be made today to five large customers. These deliveries consist of several stocks of various sizes; their total weight is given below:
Customer Weight of Shipment (lbs)
Custmer 1: 1,000
Custmer 2: 2,000
Custmer 3: 3,000
Custmer 4: 5,000
Custmer 5: 8,000
The firm has five delivery cars free to make these deliveries; operating costs and their capacities are given below.
Car Capacity (lbs) Cost/Day
Car 1: 2,000 $48.00
Car 2: 6,000 $52.00
Car 3: 8,000 $55.00
Car 4: 11,000 $67.00
Car 5: 12,000 $102.00
Also, due to distance considerations, a single car cannot deliver to customers 1 and 3 nor can a single van deliver to customers 2 and 4.
Also, policies dictate that shipment to a single customer not be divided among cars; that is, a customer receives its deliveries from a single car.
Question: Formulate an integer programming model to determine the least-cost allocation of delivery cars that guarantees all deliveries will be made.

Thanks for any help you can provide me with!!
Sara.