The amount in grams of a drug in the body t hours after taking a pill is given by $A(t) = 25(0.85)^t$.

(a) What is the initial dose given? (Include units in your answer)

(b) What percent of the drug leaves the body after each hour? %

(c) What is the amount of drug left after 7 hours? (include units in your answer, and retain at least three decimal places in your answer)