An electronics store wants to optimize how many phones and laptops are enough to keep in inventory. A phone will earn the store $120 in profits, and a laptop will earn $40. A phone requires 1 sq ft of floor space, whereas a laptop requires 4 sq ft. In total, 400 sq ft of floor space is available. The store stocks only phones and laptops. Corporate has required that at least 80% of all appliances in stock be laptops. Finally, a phone costs $400 for the store, and a laptop, $100. The store wants to spend at most $6000. Formulate an LP that can be used to maximize the store's profit.