Currently, State University can store $200$ files on hard

disk, $100$ files in computer memory, and $300$ files on tape.

Users want to store $300$ word$-$processing files, $100$

packaged$-$program files, and $100$ data files. Each month a

typical word$-$processing file is accessed eight times; a typical

packaged$-$program file, four times; and a typical data file,

two times. When a file is accessed, the time it takes for the

file to be retrieved depends on the type of file and on the

storage medium