Ariana's car was worth $12,000 at the beginning of 2000 and the value of the car decreased exponentially, decreasing by 23% each year. Define a function

f

that determines the value of Ariana's car (in dollars) in terms of the number of years

t

since the beginning of 2000.

How many years after the beginning of 2000 was Ariana's car worth $6,000?