Answer:
4 pencils / week
Step-by-step explanation:
Julie has 12 pencils.
After 2 weeks, she has 4 left, implies that: in 2 weeks she used 12 - 4 = 8 pencils.
Therefore, average rate of change = number of pencils used / period used
= 8 pencils / 2 weeks
= 4 pencils / week