Answer:

After 7.40 years it will be worth less than 21500
Step-by-step explanation:
This problem is solved using a compound interest function.
This function has the following formula:

Where:
P is the initial price = $ 34,000
n is the depreciation rate = 0.06
t is the elapsed time
The equation that models this situation is:

Now we want to know after how many years the car is worth less than $ 21500.
Then we do y = $ 21,500. and we clear t.

After 7.40 years it will be worth less than 21500