An office supplier produces desks and chairs. Each desk requires 4 units of wood, and each chair needs 3 units of wood. A desk contributes $40 to profit, and a chair has marginal profit of $25. It's required that the number of chairs produced be at least twice the number of desks produced. There are 20 units of wood available.
(a). Set up (means you need to write down) a standard LP model.