Mathematical formulation of Linear Programming Problem

A ship has three cargo loads -forward, centre and after. The capacity limits are given:

Commodity Weight (in tonne) Volume (in cu. feet)

Forward 2000 100000

Centre 3000 135000

After 1500 30000

The following cargoes are offered. The ship owner may accept all or any part of each commodity:

Commodity Weight (in tonne) Volume (in cu. feet) Profit per tonne (in Rs)

A 6000 60 150

B 4000 50 200

C 2000 25 125

In order to preserve the trim of the ship, the weight in each load must be proportional to the capacity in tonne. The cargo is to be distributed

so as to maximize the profit. Formulate the problem as LPP model.

Please help