
Answer:
a). Nadia made a total of $825 last week in commission sales
b). The total amount Nadia in commission in 2011=$42,900
Step-by-step explanation: Total amount (2011)=Average weekly commission × number of weeks in 2011  where;  Average weekly commission=$825  number of weeks in 2011=52  replacing;  Total amount (2011)=(825×52)=42,900 . The total amount Nadia in commission in 2011=$42,900.