Consider four processes, all arrive at the time 0, 2, 4 and 6 with total execution time of 20, 15, 10, and 5 units respectively. Each process spends the first 20% of execution time doing I/O, the next 80% of time doing computation. The operating system uses the shortest remaining compute time first scheduling algorithm. I/O operation can be performed in a parallel manner. What is the average turnaround time of the given processes?