Robyn bought a laptop for $1,500. It will depreciate by 15% each year that she owns it.
After one year, the laptop will depreciate by $225 (15% of $1,500).
So after one year, the value of the laptop will be $1,275 ($1,500 - $225).
If the depreciation continues at 15% per year, after two years the laptop will lose an additional $191.25 (15% of $1,275), making its value $1,083.75 ($1,275 - $191.25).
This depreciation will continue each year as long as Robyn owns the laptop.