A $32-$bit computer has two selector channels and one multiplexor channel. Each selec tor channel supports two magnetic disk and three magnetic tape units. The multiplexor channel has three line printers, two card readers, and twelve VDT terminals connected to it$.$ Assume the following transfer rates: Disk drive Magnetic tape drive Line printer Card reader VDT $1100$ Kbytes$/$s $400$ Kbytes$/$s $7\mathrm{.}8$ Kbytes$/$s $1\mathrm{.}6$ Kbytes$/$s $1\mathrm{.}2$ Kbyte$/$s