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Mathematics
OpenStudy (anonymous):

Half life of 1000 years. How long would it take to decay to 40% of that amount.

7 years ago
OpenStudy (anonymous):

too damn long

7 years ago
OpenStudy (anonymous):

solve \[.4=(\frac{1}{2})^{\frac{t}{1000}}\] for t

7 years ago
OpenStudy (anonymous):

via \[\ln(.4)=\frac{t}{1000} \ln(.5)\] \[t=1000\times \frac{\ln(.4)}{\ln(.5)}\]

7 years ago
OpenStudy (anonymous):

right mathgirl?

7 years ago
OpenStudy (anonymous):

totally

7 years ago
OpenStudy (anonymous):

hmmm. what would be the next step to get it in years

7 years ago
OpenStudy (anonymous):

whip out a calculator and type it in

7 years ago
OpenStudy (anonymous):

i did. its coming up undefined. let me try again

7 years ago
OpenStudy (anonymous):

i get 1322 rounded

7 years ago
OpenStudy (anonymous):

oh yes. i put it in wrong. ok. thanks.

7 years ago
OpenStudy (anonymous):

yw

7 years ago
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