A certain drug breaks down in the human body at a rate of 15% per hour. The initial amount of drug in the bloodstream is 12milligrams.

b). How much of the drug will be left in 4 hours?
c). How much of the drug will be left in 12 hours?
d). When will there be 8 milligrams of the drug left in the bloodstream?
e). When will there be half of the initial amount of drug left in the bloodstream?
f). How long will it take for the amount of drug to go from 6 milligrams to 3 milligrams?