A technical college department head must plan the course offerings for the next term. Student demands make it necessary to offer at least 20 core courses (each of which counts for 3 credit hours) and 20 elective courses (each of which counts for 4 credit hours) in the term. Faculty contracts dictate that a total of at least 60 core and elective courses and at least 205 total credit hours be offered. Each core course taught costs the college an average of $2,600 in faculty salaries and each elective course costs $3,000. How many each of core and elective courses should be scheduled so that total faculty salaries are kept to a minimum?