Let E be the total amount earned in dollars, and let t be the number of hours worked:
E = 7.5 * t
The above equation can be rearranged to find the number of hours worked, given the total amount earned:
t = E/7.5
Plugging the value of $33.75 into the last equation we get:
t = 33.75/7.5
t = 4.5 hours
The answer is: 4.5 hours.
