SOLUTION: Suppose your salary is increasing at a rate of 3.5% per year. Then your salary will double in approximately years?

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Question 793873: Suppose your salary is increasing at a rate of 3.5% per year. Then your salary will double in approximately years?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
At the end of 1 yr
Let +s+ = the starting salary
Let +S%5Bn%5D+ = the current salary at the
end of year number +n+
+S%5B1%5D+=+s+%2B+.035s+
+S%5B1%5D+=+s%2A%28++1+%2B+.035+%29%5E1+
-------------------------
+S%5B2%5D+=+%28+s+%2B+.035s+%29%2A1+%2B+%28+s+%2B+.035s+%29%2A.035+
+S%5B2%5D+=+%28+s+%2B+.035s+%29%2A%28+1+%2B+.035+%29+
+S%5B2%5D+=+s%2A%28+1+%2B+.035+%29%5E2+
------------------------
So, the rule is:
+S%5Bn%5D+=+s%2A%28+1+%2B+.035+%29%5En+
------------------------
The problem is to find +n+ when +S+=+2s+
+2s+=+s%2A%28+1+%2B+.035+%29%5En+
+2+=+%28+1+%2B+.035+%29%5En+
+2+=+1.035%5En+
Take the log of both sides
+log%28%282%29%29+=+n%2Alog%28%28+1.035+%29%29+
+n+=+log%28%282%29%29+%2F+log%28%281.035%29%29+
I can't find my calculator. Work this out and
round +n+ off to the closest integer