Answer:she spent 10 hours working in her aunt's store last week.
Step-by-step explanation:
Let x represent the number of hours that Lee spent working at the movie theater.
Let y represent the number of hours that Lee spent working at her aunt's store.
Lee worked a total of 30 hours at the movie theater and her aunt's store. This means that
x + y = 30
Her combined pay from the jobs was $240. She earned $9 per hour working at the movie theater and $6 per hour working in her aunt's store. This means that
9x + 6y = 240 - - - - - - - - - -1
Substituting x = 30 - y into equation 1, it becomes
9(30 - y) + 6y = 240
270 - 9y + 6y = 240
- 9y + 6y = 240 - 270
- 3y = - 30
y = - 30/ - 3 = 10 hours
. Filling in accordingly, 
. This simplifies to 
and 36=6x. Therefore, x = 6 so the bases are 6 and 12.