answer algorithm question in Computer sicence

I need someone who can answer for following two question ? 1. Four processes A through D, arrive at a computer system at 0, 1, 2, and 3, respectively. They have estimated execution times of 8, 7, 9, and 6. Their priorities are 2, 4, 3, and 1, respectively, with 1 being the highest priority. The priorities are used only for priority scheduling (i.e., they are ignored in other scheduling algorithms). All jobs are completely CPU bound. The OS does not know when a process will arrive, until it arrives. For each of the following scheduling algorithms, determine the average response time. Ignore context-switching overhead. (a) round robin scheduling with time slice = 2 (b) pre-emptive priority-based scheduling (c) shortest job first scheduling 2. Two periodic processes are ready to run at time 0: P1(8,4) and P2(5,2.5) (8 and 5 are intervals (periods), 4 and 2.5 are processing time). Draw a timeline for each process to show when they are running and when they are waiting, assuming that there is no context-switching overhead. (a) The system uses EDF (earliest deadline first) scheduling. (b) The system uses RM (rate monotonic) scheduling.