a) You know that she works 40 hours per week.
You know that there are 365 days in a year and there are 7 days in a week. Then, the number of hours she regularly work per year, can be found as following:

Where "x" is the number of hours she regularly work per year.
Solving for "x", you get:

Debra's regularly hour wage is $8.50 and, then, multiply the value of "x" by $8.50 in order to calculate her annual salary (in dollars):

b) If she works 50 weeks per year, you can set up the following proportion to find "x":

Solving for "x", you get:

Multiply the value of "x" by $8.50 in order to calculate her annual salary (in dollars):

The answers are:
a) $17,728.54
b) $22,160.69