A certain radioactive element decays over time according to the equation y=A(1/100)^t/300 where A= the number of grams present initially and t=time in years. If 1000 grams were present initially, how many grams will remain after 900 years?

Question

A certain radioactive element decays over time according to the equation y=A(1/100)^t/300 where A= the number of grams present initially and t=time in years.  If 1000 grams were present initially, how many grams will remain after 900 years?

zehanz · Answer

Set A=1000 and t=900 in the formula:$$y=1000\cdot \left( \frac{ 1 }{ 100 } \right)^{\frac{ 900 }{ 300 }}=1000\cdot \left( \frac{ 1 }{ 100 } \right)^3=...$$

anonymous · Answer

so what would the answer be? I plugged it into my calculator, but its not one f the answer choices..

anonymous · Answer

please help(:

zehanz · Answer

Calculator not needed, because all numbers are powers of 10: 
$1000\cdot(1/100)^3=10^3 \cdot(10^{-2})^3=10^3\cdot 10^{-6}=10^{-3}=0.001$.

If this is not among your answer options, then are you sure the original formula is correct?