A doctor prescribes 125 milligrams of a therapeutic drug that decays by about 10% each hour.

Question

A doctor prescribes 125 milligrams of a therapeutic drug that decays by about 10% each hour. To the nearest hour, what is the half-life of the drug?

Answer 1

75 = 125(e)^-0.10t

1/2 = e^--0.1t

ln.5 = -0.1t

t = 1n.5/-0.1 = -0.6931/-.1 = 6.931 hours or half life

nearest hour is 7