P$7-4.$ A multiprogramming operating system uses an apportioning scheme and divides

the $60$ MB of available memory into four partitions of $10$ MB$,12$ MB$,18$ MB$,$ and $20$

MB$.$ The first program to be run needs $17$ MB and occupies the third partition. The

second program needs $8$ MB and occupies the first partition. The third program needs

$10\mathrm{.}5$ MB and occupies the second partition. Finally, the fourth program needs $20$ MB

and occupies the fourth partition.

What is the total memory used?

What is the total memory wasted?

What percentage of memory is wasted?