# Math Help - need help!

1. ## need help!

so i'm just learning how to do these questions, and i'm not sure i'm doing it right.

Amy invests $4000 at 8%/a, compounded quarterly. How long will it take for the$4000 to grow to \$5000?

is this the way you solve? am i leaving anything out?

5000=4000(1+0.08/4)^n

2. 5000=4000(1+0.08/4)^n

It should be 5000=4000(1+0.08/4)^4n

3. remember that the growth formula is $(1+\frac{1}{n})^{n'}$.

where n is the number of compoundings. All this thing saysn is that if we take what we originally had (1) and we take a smaller and smaller return, we'll get more and more compoundings. it's kind of nice to compare (when n=n') n=1, n=10, n=50, n=100, etc... Somethins going on there.
In your case the growth is being compounded quarterly ie n=4, but your don't nnow what n' equals so you gotta solve for it.