<PRE><B>Question 185278</B>
A certain reproductive element decays according to A(t) = A(0,e^-0.032t). Where t is years. How long will it take to go from 800 grams to 85 grams? (nearest year)
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A(t) = A(0,e^-0.032t). 

85 = 800*e^(-0.032t)

e^(-0.032t) = 0.10625

Take the natural log of both sides to get:
-0.032t = -2.24196

t = 70 years (nearest year)</PRE>