SOLUTION: Jordan has invested $4000 in an account that earns 3.6% compounded annually. Approximately how many years will it take for his money to double

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Question 1141069: Jordan has invested $4000 in an account that earns 3.6% compounded annually. Approximately how many years will it take for his money to double
Found 2 solutions by greenestamps, josgarithmetic:
Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


The initial amount is irrelevant. We simply want to know when the original amount doubles.

The annual growth factor is 1 plus 3.6%, or 1.036. The growth factor after n years is (1.036)^n. We want to know when the growth factor reaches 2:

1.036%5En+=+2

Use logarithms and/or a graphing calculator.

Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Compounded ANNUALLY.

1.036%5E1=1.036
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1.036%5E2=1.0733
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1.036%5E4=1.15196
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1.036%5E8=1.327
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1.036%5E11=1.476
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highlight%28n=20%29

1.036%5E20=2.029



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2=1.036%5En
log%28%282%29%29=n%2Alog%28%281.036%29%29
n=log%28%282%29%29%2Flog%28%281.036%29%29
n=19.60, close to 20 is better.