Problema Solution

A loptop computer loses 5% of its value each month after it is purchased. it was purchased for $6000.write a function for its value as a function of time.

a) what is the value of the laptop after 3 month?

b) In which month after it is purchased does the laptop's worth fall below $2000?

Answer provided by our tutors

let 't' represent the time in months after the computer is purchased


f(t) = 6,000(1 - 0.05)^t


a) what is the value of the laptop after 3 month?


t = 3 months


f(3) = 6,000(1 - 0.05)^3


f(3) = $5,144.25


the value of the laptop after 3 months is $5,144.25.



b) In which month after it is purchased does the laptop's worth fall below $2000?


we need to find t such that f(t)<2000 that is


6000(1 - 0.05)^t < 2000


t > 21.4


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for t = 22 months we have


f(22) = 6000(1 - 0.05)^22


f(22) = $1,941.20 < $20000


for t = 21 moths we have


f(21) = 6000(1 - 0.05)^21


f(22) = $2,043.37 > $20000


22 moths after the purchase the computer is worth less than $2,000.