Question

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Answer 1

So you do not have a specific half life formula, and need to find it.

Answer 2

OK, so show the work.

Answer 3

Sure.

Answer 4

Looks pretty good. So far I got to:
\[100=A_0e^{-x30};\\
30=A_0e^{-x120}\implies\\
100/e^{-x30}=A_0\implies\\
30=(100/e^{-x30})e^{-x120}\implies\\
ln(30)=ln((100/e^{-x30})e^{-x120})\implies\\
ln(30)=ln(100)-ln(e^{-x30})+ln(e^{-x120})\implies\\
ln(30)=ln(100)+x30-x120\]

Answer 5

Yah, I just took it to finding x, or your k, and I got the same number.

Answer 6

So you took the tacktic that it was solving two equations with two unknowns and an added twist involing e and ln. All 100% the right way to go.

Answer 7

Not expecially. I need to work on calc more these days.

Answer 8

np. Have fun!

Answer 9

Also got the same \(A_0\)

Answer 10

And with those two, the rest is easy.