A bank is retrofitting part of its vault to hold safety deposit boxes. It plans to build safety deposit boxes approximately 6 feet high along the walls on both sides of a 20-foot corridor. Hence, the bank will have 240 square feet of wall space to use. It plans to offer two sizes of safety deposit box: large and small. Large boxes (which consume 122.4 square inches of wall space) will rent for $40 per year. Small boxes (which consume 72 square inches of wall space) will rent for $30 per year. The bank believes it will need at least 350 total boxes, at least 80 of which should be large. It hopes to maximize revenue for safety deposit boxes. How many boxes of each size should the bank’s design provide?