<PRE><B>Question 852441</B>
The radioactive substance uranium-240 has a half-life of 14 hours. The amount A(t) of a sample of uranium-240 remaining (in grams) after t hours is given by the following exponential function:


{{{A(t)=2800(1/2)^(t/14)}}}
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Initial amt is A(0) = 2800 gm
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{{{A(40) = 2800(1/2)^(40/14)}}}
= 386 gm
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Just calculator work.
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