you have a new computer for $1500. the computer depreciates by 25% annually. when will the computer have a value of $650?

Answer 1

depreciates 25% means that it is worth 75% of the previous year's value...

1500 * (0.75)^n = 650

(0.75)^n = 650/1500 = 65/150 = 13/30

takes log of both sides

n * log (0.75) = log(13/30)

n = log(13/30)/log(0.75)

n = 2.90684788618792...

So almost three years

check:

0.75 * 1500 = 1125

0.75 * 1125 = 843.75

0.75 * 843.75 = 632.8125

yep

Answer 2