3. Suppose a disk drive in your system has a rotation speed of 7,200 rpm. and seek times of 0.68 ms track-to-track, or 21 ms full stroke (inner edge to outer edge). (a) What is the average latency to access this drive? (b) If the sustained read rate is 42 Mbits/sec, how much more time after the average latency (you calculated above) will it take to read 750 Kbytes (assuming all those bytes are in sequential sectors on the same track)? How long to write that same amount of data if the sustained write speed is 32 Mbits/sec?