A 60Co source (which has a half-life of 5.2714 y) is labeled 4.00 mCi, but its present activity is found to be 1.6 x 10' Bq Randomized Variables R-1.6 x 107 Bq 50% Part (a) What is the present activity in mCi? R- 0.432 Correct! 50% Part (b) How long ago did it actually have a 4.00 mCi activity in years? Grade S Deducti Potential