2. You need to buy some new filing cabinets. You know that it is 10 R. O. per unit to buy Cabinet X, which holds 8 cubic feet of files and requires floor space of 6 square feet. On the other hand, it is 20 R. O. for every unit of Cabinet Y which requires floor space of 8 square feet and holds about 5 cubic feet of files. For this purchase, you have been given 140 R. O. but don’t really have to spend all of it. The space in the office only has room for a maximum of seventy-two square feet of furniture. To maximize the volume of files you can store, how many of what model do you need to buy?