Algebra work problem help

Question

A sample of 250 grams of radioactive substance decays according to the function A(t) = 250e -0.033t, where t is the time in years. How much of the substance will be left in the sample after 20 years?

Answer 1

A(t) = 250e^-0.033t

A(20) = 250e^-0.033(20)

A(20) = 250e^-0.66

A(20) ≈ 250(0.516851334)

A(20) ≈ 129.212834

 

Approximately 129 grams remain after twenty years.