Brianna bought a new car for $15000. each year the value of the car deprecaites by 30% of its value of the previous year. in how many years will the car be worth only $500?

The formula is
A=p (1-r)^t
A future value 500
P current value 15000
R rate of depreciation 0.3
T time?
500=15000 (1-0.3)^t
Solve for t
Divide both sides by 15000
500/15000=(1-0.3)^t
Take the log for both sides
Log (500/15000)=t×log (1-0.3)
Divide both sides by log (1-0.3)
T=(log(500÷15,000)÷log(1−0.3))
T=9.5 years round your answer to get 10 years

Hope it helps!