Question

a laptop computer is purchased for $4500. Each year, its value is 80% of its value the year before. After how many years will the laptop computer be worth $1000 or less?​

Answer 1

So after 7 year price of the laptop will be less than $1000

Explanation:

We have given price of the laptop is $4500

Its price is 80% of if its value in every next year

So depreciation rate = 100 - 80 =20%

For depreciation we know that

`V=P(1-r)^n`

Here V is final value and P is present value

So
`1000=4500(1-0.2)^n`

`0.2222=(0.8)^n`

Taking log both side

`log0.222=nlog0.8`

n = 6.74

So after 6.74 year the price of the laptop will be less than $1000