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Thread: [Resolved] Easy Question, The Sequel

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  1. Nov 4th, 2002, 07:25 PM #1
    The Hobo
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    [Resolved] Easy Question, The Sequel

    Okay, I'm presented with this problem:

    The half-life of element X is 9 hours. If 80mg are present now, how much will exist after 2 days?
    So I used the formula A(t) = A0 * e ^ kt

    Code:
    .5 = e ^ 9k
ln .5 = 9k
k = ln (.5)/9
k = -0.0077
    So now I have A(t) = A0 * e ^ -.0077t

    So I do:

    Code:
    A = 80e ^ -.0077(48)
A = 3810.55
    Which obviously isn't correct. What am I doing wrong?
    Last edited by The Hobo; Nov 5th, 2002 at 12:18 AM.
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