A computer manufacturing company wants to develop a monthly plan for shipping finished products from three of its manufacturing facilities to three regional warehouses. It is thinking about using a transportation LP formulation to exactly match capacities and requirementsData on transportation costs $($dollars per unit$),$ capacities, and requirements are given below. $($Let x iq represent the flow from plant$/$ to warehouse Warehouse $1$ Warehouse $2$ Warehouse $3$ Capacities Plant $12\mathrm{.}401\mathrm{.}622\mathrm{.}083,750$ Plant $23\mathrm{.}195\mathrm{.}611\mathrm{.}756,750$ Plant $34\mathrm{.}133\mathrm{.}153\mathrm{.}083,250$ Requirement $8\mathrm{.}25$ deg $2,2503,250($a$)$ How many variables are involved in the LP formulation $?$