Sure, let me help you on this one!
We are starting with a value of $20,000.
We will experience a 10% price drop in the first five years (2*5)
20,000 times 0.90 equals to 18,000
$18,000 dollars after five years.
We will also experience a 12.5% the following five years.
18,000 times 0.875 equals to 15,750.
The answer to this question is $15,750.