Radium-226, in grams, decays in such a way that after t years, the amount left over can be modeled by the equation A (t)= 450e^-0.0004t. How many grams of Radium-226 will remain after seven years? Round your answer to the nearest tenth.
To find the amount of Radium-226 remaining after seven years, we will substitute t = 7 into the equation A(t) = 450e^(-0.0004t):
A(7) = 450e^(-0.0004 * 7) ≈ 450e^(-0.0028) ≈ 450 * 0.997128 ≈ 448.71
Therefore, approximately 448.7 grams of Radium-226 will remain after seven years.