Will purchased a car for $21,000. If V = 21,000(0.85)x gives the value of the car after x years, how many years will it take for the car to be worth half of its original value?

Respuesta :

Answer:

4 years will it take for the car to be worth half of its original value.

Step-by-step explanation:

Given : Will purchased a car for $21,000. If [tex]V = 21,000(0.85)^x[/tex] gives the value of the car after x years.

To find : How many years will it take for the car to be worth half of its original value?

Solution :

[tex]V = 21,000(0.85)^x[/tex] gives the value of the car after x years.

The car to be worth half of its original value i.e. [tex]V=\frac{21000}{2}=10500[/tex]

[tex]10500 = 21000(0.85)^x[/tex]

[tex]\frac{10500}{21000}=(0.85)^x[/tex]

[tex]0.5=(0.85)^x[/tex]

Taking log both side,

[tex]\log (0.5)=x\log(0.85)[/tex]

[tex]x=\frac{\log (0.5)}{\log(0.85)}[/tex]

[tex]x=4.26[/tex]

Approximately the number of years it will take is 4 years.