Answer
-$\$500$ per year
This means that the copier's value depreciates by $\$500$ per year after its purchase.
Work Step by Step
2 years after purchase, the value of the copier is $\$2000$.
4 years after purchase, the value of the copier is $\$1000$.
The increase (or decrease) in value is:
$=\$1000-\$2000=\$1000$
The time is:
$=4-2=2$ years
Thus, the average rate is:
$=\dfrac{-\$1000}{2 \text{ years}}=-\$500$ per year
