SOLUTION: CAN SOMEONE HELP WITH THIS WORD PROBLEM? Strontium-90 is a waste product from nuclear fission reactors. It's half-life is 28 years and its decay model is A=A(subscript 0)e^-0.0247

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION: CAN SOMEONE HELP WITH THIS WORD PROBLEM? Strontium-90 is a waste product from nuclear fission reactors. It's half-life is 28 years and its decay model is A=A(subscript 0)e^-0.0247      Log On


   

Question 201484: CAN SOMEONE HELP WITH THIS WORD PROBLEM? Strontium-90 is a waste product from nuclear fission reactors. It's half-life is 28 years and its decay model is A=A(subscript 0)e^-0.024755t. Suppose a nuclear accident occurs and releases 50 grams of strontium-90 into the biosphere. How long will it take for strontium-90 to decay to a level of 20 grams?
Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
20 = 50 e^(-.024755 t)

dividing by 50 ___ .4 = e^(-.024755 t)

taking natural log ___ ln(.4) = -.024755 t

dividing by -.024755 ___ [ln(.4)] / -.024755 = t


you can do this on your calculator ___ it should have a natural log (ln) key