Answer:
Option D.
Step-by-step explanation:
It is given that Tammy bought a car for c dollars.
Original price of car = c
Price of car after 1 year = 0.93c
We need to find the change in the value of Tammy's car.
[tex]Change\%=\dfrac{\text{New Price - Original price}}{\text{Original price}}\times 100[/tex]
[tex]Change\%=\dfrac{0.93c-c}{c}\times 100[/tex]
[tex]Change\%=\dfrac{-0.07c}{c}\times 100[/tex]
[tex]Change\%=-0.07\times 100[/tex]
[tex]Change\%=-7\%[/tex]
Here negative sign represents that the value of is decreasing by 7%.
Therefore, the correct option is D.