["Find total units: 3 + 7 = 10 units. Each unit = 80 / 10 = 8 rooms.","Single rooms = 3 x 8 = 24. Occupied:vacant = 2:1 so occupied singles = 2/3 x 24 = 16.","Double rooms = 7 x 8 = 56. Occupied:vacant = 5:2 so occupied doubles = 5/7 x 56 = 40. Total occupied = 16 + 40 = 56."]