SOLUTION: f $350 grows into $500 in 3 years, what is the annual interest rate assuming that interest in compounded annually?

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Question 960779: f $350 grows into $500 in 3 years, what is the annual interest rate assuming that interest in compounded annually?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
+A+=+P%2A%28+1+%2B+r%2Fn+%29%5E%28+n%2At+%29+
+500+=+350%2A%28+1+%2B+r%2F1+%29%5E%28+1%2A3+%29+
+500+=+350%2A%28+1+%2B+r+%29%5E3+
+10+=+7%2A%28+1+%2B+r+%29%5E3+
Take the log of both sides
+log%28+10+%29+=+log%28+7+%29+%2B+log%28+1+%2B+r+%29%5E3+
+1+=+.8451+%2B+log%28+1+%2B+r+%29%5E3+
3%2A+log%28+1+%2B+r+%29++=+.1549+
+log%28+1+%2B+r+%29+=+.05163+
+1+%2B+r+=+10%5E.05163+
+1+%2B+r+=+1.1262+
+r+=+.1262+
The annual interest rate is 12.62%
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check:
+10+=+7%2A%28+1+%2B+r+%29%5E3+
+10+=+7%2A%28+1+%2B+.1262+%29%5E3+
+10+=+7%2A1.1262%5E3+
+10+=+7%2A1.42853+
+10+=+9.99972+
OK -error due to rounding off