Question

answer is not 79,64, or 69

Hospitals use radioactive tracers in many medical tests. After the tracer is used, must be stored as radioactive waste until its radioactivity has decreased enough for it to be disposed of as ordinary Chemical waste. For the radioactive isotope ledine-131, the proportion of radioactivity remaining after days is 0.087. How soon will the proportion of radioactivity decrease to 0.004 so that it can be disposed of as ordinary chemical waste? (Round your answer to the nearest day.) 69 X days Need Help? Submit Answer

Answer 1

remaing e r Proportion of radioactivity -0.067t remaining after t days proportion reduced to 0.004 -0.067t then when 0.004 - taking log en (0.004) = -(0.067) t - ln(0.004) 82.5 days t - Il 0.067