Janelle just read that her laptop, which cost $3600 new, depreciates by 10% of its value every year. If this estimate is accurate, how much will the computer be worth in 6 years?

Answer 1

P(t) = 3600·0.9^t; P(6) = 3600·9.9⁶ = $1913.19

Answer 2

As Yefim was saying, if the computer is losing 10% of its value every year, we could say that it's only 90% of its old value in each new year. So you're simply multiplying by that "0.9" 6 times (i.e. 0.9⁶). This is what is giving you the final depreciated value of $1913.19.