Answer:
![A = 20,000(0.85)^t](https://tex.z-dn.net/?f=A%20%3D%2020%2C000%280.85%29%5Et)
Step-by-step explanation:
We will use the formula for compound interest here
where ![A = p( 1 + r)^t](https://tex.z-dn.net/?f=A%20%3D%20p%28%201%20%2B%20r%29%5Et)
A=future value for any sum
P=present value of the sum
r= yearly interest rate, it should be expressed in decimal
t=time period , it should be in years
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given in the problem
p = $20,000
r = 15% (in decimal 15/100 = 0.15)
t is the time for which equation is to be model to find future value p
since, rate is for depreciation we need to take negative value of rate as value for computer will decrease
thus
r = -0.15
using the above values in formula ![A = p( 1 + r)^t](https://tex.z-dn.net/?f=A%20%3D%20p%28%201%20%2B%20r%29%5Et)
![A = p( 1 + r)^t\\A = 20,000(1 - 0.15)^t\\A = 20,000(0.85)^t](https://tex.z-dn.net/?f=A%20%3D%20p%28%201%20%2B%20r%29%5Et%5C%5CA%20%3D%2020%2C000%281%20-%200.15%29%5Et%5C%5CA%20%3D%2020%2C000%280.85%29%5Et)
Thus, model equation for the value of the computer is ![A = 20,000(0.85)^t](https://tex.z-dn.net/?f=A%20%3D%2020%2C000%280.85%29%5Et)