Alex upgraded his MS$-$DOS to Windows NT $($sort of$)$ that supports multitasking with quantum $50$s $($no kidding$).$ Job J and A and B as before. The setup for J and A$,$B is that of $2\mathrm{.}3$ above: A job J consists of two tasks A and B$.$ Job J completes when its last task completes its execution. Task A with $100$s CPU time $($just as in $2\mathrm{.}2)$ followed by $50$s I$/$O arrives at t$=30$s$,$ the system is empty and A starts execution immediately. Task B with $250$s CPU and $100$s I$/$O arrives at t$=50$s$.$ There is no other program other than A$,$B$.$

$5\mathrm{.}1$ What is the CPU utilization then? $($drop decimal$)$ utilizing simple integer fraction

$5\mathrm{.}2$ What is the turnaround time of A$?$

$5\mathrm{.}3$ What is the turnaround time of B$?$