SOLUTION: how many years would it take to double $100 if it earned interest at a rate of 8% per year?

Algebra ->  Algebra  -> Customizable Word Problem Solvers  -> Finance -> SOLUTION: how many years would it take to double $100 if it earned interest at a rate of 8% per year?      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com
Ad: Algebrator™ solves your algebra problems and provides step-by-step explanations!
Ad: Algebra Solved!™: algebra software solves algebra homework problems with step-by-step help!

   

Question 220267: how many years would it take to double $100 if it earned interest at a rate of 8% per year?
Answer by Theo(2973) About Me  (Show Source):
You can put this solution on YOUR website!
100%2A%281.08%29%5Ex+=+200
log%28%28100%2A1.08%29%5Ex%29+=+log%28%28200%29%29
This becomes:
log%28%28100%29%29+%2B+x%2Alog%28%281.08%29%29+=+log%28%28200%29%29
This becomes:
x+=+%28log%28%28200%29%29+-+log%28%28100%29%29%29%2Flog%28%281.08%29%29
This becomes:
x = 9.006468342
-----
to prove this is true, substitute in original equation to get:
100%2A%281.08%29%5E9.006468342+=+200
This becomes:
200 = 200 confirming the answer of x = 9.006468342 is good.
-----
It would take 9.006468342 years to double your money at 8% compounded yearly.
-----