SOLUTION: The function D(h)=7e^-0.3h can be used to find the number of milligrams D of a certain drug that is in a patient's bloodstream h nours after the drug has been administered. a, how

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Question 965088: The function D(h)=7e^-0.3h can be used to find the number of milligrams D of a certain drug that is in a patient's bloodstream h nours after the drug has been administered.
a, how many milligrams will be present after 2 hours?
b, when the number of milligrams reaches 1, the drug is to be administered again. After how many hours will the drug need to be administered?
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Not this, D(h)=7e^-0.3h
but instead
THIS: D(h)=7e^(-0.3h)

The rendering will give the more standard-like notation, D%28h%29=7e%5E%28-0.3h%29.

Question (a) is fairly simple.

Question (b):
1=7%2Ae%5E%28-0.3h%29
ln%281%29=ln%287%29%2Bln%28e%5E%28-0.3h%29%29
0=ln%287%29-0.3h%2A1
0.3h=ln%287%29
highlight%28h=ln%287%29%2F%280.3%29%29