3. The half-life of a certain drug in the human body is 8 hours how long it would take for a dose of this drug to decay to 0.1% of its initial level?
(1/2)^(t/8) = 0.1
t = 79.72 hours
Makes sense, since .1% = 1/1000
and 10 half-lives (80 hours) is 1/1024