Example D - Without calculator version: Radioactive Cobalt-60 is used to treat cancer patients and has a half-life of 5.26 years. The amount A (in grams) of Cobalt-60 at time t (in years) is given by: A(t) = Ape (tin 2)/5.26 where Ao is the original amount. A sample that originally had 12 grams of Cobalt-60, now has 4 grams. How old is the sample? Answer with an exact value. Answers: -5.26 In 5.26 In 3 (a) In 2 years old (c) years old In 2 (b) 5.26 In ( ) years old (d) In (3 years old 5.26 In 2 (e) Not sure! G MAT135H LEC slides