Each year a car depreciated by 9%. Calculate the number of years after which the value of the car is 47% of it's original value.
I'm aware of the compound interest formula but I don't know if it would be any use here or how to reverse it because I'm not looking for a precise number. Should I create a number such as x and try and somehow change the compound interest formula so it's inverse?
what's "reverse" and "inverse"?
Once more, to find the number of periods, logs ARE REQUIRED.
Finding the "value left" after a GIVEN period is a different story: (1 + i)^n
With i = -.09 and n = 8: (1 - .09)^8 = .91^8 = .47025...