7-18 The dean of the Western College ofBusiness must plan the schools course offerings for the fallsemester. Student demands make it necessary to offer at least 30undergraduate and 20 graduate courses in the term. Facultycontracts also dictate that at least 60 courses be offered intotal. Each undergraduate course taught costs the college anaverage of $2500 in faculty wages and each graduate course costs$3000. How many undergraduate and graduate courses should betaught in the fall so that total faculty salaries are kept to aminimum?