Suppose there are four processes A, B, C and D, which arrive at 3, 3, 100, 200 msec respectively. The lengths of process A, B, C and D are 50, 100, 15 and 25 msec, respectively. Ignore the process switching overhead.

a. Compute the average turnaround time if you are using shortest job first algorithm (non-preemptive).

b. Compute the average turnaround time if you are using round robin algorithm, assuming the CPU quanta is 30 ms (preemptive).