The Energetic Company needs to make plans for the energy systems for a new building. The energy needs in the building fall into three categories: (1) electricity, (2) heating water, and (3) heating space in the building. The daily requirements for these three categories (all measured in the same units) are

The three possible sources of energy to meet these needs are electricity, natural gas, and a solar heating unit that can be installed on the roof. The size of the roof limits the largest possible solar heater to 30 units, but there is no limit to the electricity and natural gas available. Electricity needs can be met only by purchasing electricity (at a cost of $50 per unit). Both other energy needs can be met by any source or combination of sources. The unit costs are

The objective is to minimize the total cost of meeting the energy needs.
(a) Formulate this problem as a transportation problem by constructing the appropriate parameter table.

Electricity Water heating Space heating 20 units 10 units 30 units Electricity Natural Gas Solar Heater Water heating Space heating $90 80 $60 50 $30 40