$260 
I don’t know what model/formula you are supposed to be using. 
But what I did first was calculated what 30% of 2700$ is. 
2700 x .3 = 810
So it depreciates $810 per year. 
$810 x. 3 years = 2430
2700 - 2430 = 260
In three years, the laptop will be worth $260