SOLUTION: The​ half-life of radium is 1690 years. If 40 grams are present​ now, how much will be present in 440 ​years? _______ grams? ​(Do not round until the fi

Algebra ->  Customizable Word Problem Solvers  -> Misc -> SOLUTION: The​ half-life of radium is 1690 years. If 40 grams are present​ now, how much will be present in 440 ​years? _______ grams? ​(Do not round until the fi      Log On

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Question 1088725: The​ half-life of radium is 1690 years. If 40 grams are present​ now, how much will be present in 440 ​years?
_______ grams?
​(Do not round until the final answer. Then round to the nearest thousandth as​ needed.)
Answer by josgarithmetic(39616) About Me  (Show Source):
You can put this solution on YOUR website!
p=I%2Ae%5E%28-kt%29
1%2F2=1%2Ae%5E%28-k%2A1690%29
ln%281%2F2%29=0-k%2A1690
-1690k=ln%281%2F2%29
-1690k=-ln%282%29
k=ln%282%29%2F1690
k=0.0004101

-
I=40 grams
t=440 years
highlight_green%2840%2Ae%5E%28-0.0004101%2A440%29%29
33 grams