SOLUTION: David invests $2,000 at 8% interest. About how long will it take for him to double his investment? (e.g, to $4,000)?

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Question 515124: David invests $2,000 at 8% interest. About how long will it take for him to double his investment? (e.g, to $4,000)?
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
David invests $2,000 at 8% interest. About how long will it take for him to double his investment?David invests $2,000 at 8% compound interest.
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A(t) = P(1+(r/n))^(nt)
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4000 = 2000(1+ 0.08/1))^(1*t)
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(1+0.08)^t = 2
t*log(1.08) = log(2)
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time = log(2)/log(1.08) = 9 years
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Cheers,
Stan H.
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