Consider that the half-life of Polonium-210 is 140 days.
What approximate daily percentage of decay does Polonium-210 demonstrate? (Round to two decimals.)
(Hint: use the Rule of 70 backwards by dividing by the half-life period instead of the rate.)
What percentage of the original amount of Polonium-210 would be left after 525 days of decay? % (Round to two decimals.)