Originally Posted by

**Demosthenes11**
Has he taught you what 'e' really is yet?

I'm guessing n is the rate, so if it was decreasing quarterly, we would use 4 for n. But because it is infinately decreasing, we just treat (1+r/n)^nt as e^rt (which you can prove using limits later on).

Since you want to find when the car will be worth 12,450, you set that as A.

12,450=Pe^rt

r=.1, or 10%

P= 25,900

t= the amount of time it takes for the price to get to 12,450, which is what you want, so you solve for that.

.5 = e^.1t

ln |.5| = .1t

Divide by .1 and you have your answer.

You need to do ln to cancel out the e

For my test on that shit, we had to prove e lol

Edit: lol, forgot to add P, thought it didn't look right