I can see the output that you are looking for, however, I don't know the
table structure and whether or not you need help with the first two queries
or just the third. I will say that the third query requires a union all and an
aggregate query.
You should first union the two tables, then wrap that as a subquery and
do a sum on the amount and net columns. Make sure that you order by name.
At least that is the way I assume that your professor wants the query to be written...