Question 665070
Let d = the amount of monthly dues, and h be the number of hours worked in the month.  We are told that
 
d = 5.00 + 0.15*h
 
We need to solve for h.  First subtract 5.00 from both sides:
 
d - 5.00 = 0.15*h
 
Then divide both sides by 0.15:

(d - 5.00)/0.15 = h
 
h = (d - 5.00)/0.15
 
Plugging in d = 30.20 for March, we have
 
h = (30.20 - 5.00)/0.15
 
h = 25.20/0.15
 
h = 168 hours