Answer: 45,000.
Step-by-step explanation:
The equation of inverse variation is given by:-
[tex]k=xy[/tex]
, 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,
[tex]x_1=3,\ y_1=15000\\\\x_2=5,\ y_2=9000[/tex]
Then, [tex]k=x_1y_1=3\times15000=45,000[/tex]
or [tex]k=x_2y_2=5\times9000=45,000[/tex] [answer is same in both cases.]
Hence, the constant of proportionality in this inverse variation is 45,000.
