SOLUTION: suppose that a certain radioactive substance has a half life of 20 years. if there is presently 2500 milligrams of the substance, how much, to the nearest milligram will remain aft

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Question 434856: suppose that a certain radioactive substance has a half life of 20 years. if there is presently 2500 milligrams of the substance, how much, to the nearest milligram will remain after 40 years? after 50 years?
Found 2 solutions by stanbon, solver91311:
Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website!
suppose that a certain radioactive substance has a half life of 20 years. if there is presently 2500 milligrams of the substance, how much, to the nearest milligram will remain after 40 years?
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f(40) = 2500(1/2)^(40/20)
f(40) = 2500(1/4)
f(40) = 625 ml
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after 50 years?
f(50) = 2500(1/2)^(50/20)
f(50) = 2500(1/2)^2.5
f(50) = 2500*0.176788 = 441.94 ml
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Cheers,
Stan H.
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Answer by solver91311(24713) (Show Source):
You can put this solution on YOUR website!

Calculate when the ratio of to is 0.5 and

Then re-write the function using the calculated value of

You can do your own calculator work.

John

My calculator said it, I believe it, that settles it