Answer: 45,000.
Step-by-step explanation:
The equation of inverse variation is given by:-
![k=xy](https://tex.z-dn.net/?f=k%3Dxy)
, where k is the constant of proportionality.
Given: After owning the car for 3 years, its value is $15,000. After owning the car for 5 years, its value is $9,000.
Here,
![x_1=3,\ y_1=15000\\\\x_2=5,\ y_2=9000](https://tex.z-dn.net/?f=x_1%3D3%2C%5C%20y_1%3D15000%5C%5C%5C%5Cx_2%3D5%2C%5C%20y_2%3D9000)
Then, ![k=x_1y_1=3\times15000=45,000](https://tex.z-dn.net/?f=k%3Dx_1y_1%3D3%5Ctimes15000%3D45%2C000)
or
[answer is same in both cases.]
Hence, the constant of proportionality in this inverse variation is 45,000.