Answer:
O = amount of own brand
L = amount of local brand
N = amount of national brand
maximize = 0.97O + 0.83L + 0.69N
constraints:
space ⇒ O + L + N = 324
N ≥ O + L
N ≥ 3O
L ≤ 120
O,L,N ≥ 0
O,L,N are integers (whole numbers)
optimal solution using Solver = 540 + 108L + 162N
maximum profit = $253.80