A gram sample of a substance thats used for drug research has a k-value of 0.1455. Find the substance's half-life,in days. Round your answer to the nearest tenth.

Question

anonymous · Answer

not sure what a K value is, but my best guess is to solve 
$$\large e^{-1.455t}=.5$$ for $t$

anonymous · Answer

A 40 gram sample of a substance thats used for drug research has a k-value of 0.1455. Find the substance's half-life,in days. Round your answer to the nearest tenth.

anonymous · Answer

sorry

anonymous · Answer

makes no difference what you start with
half life is half life

anonymous · Answer

if you start with 40 you will get 20 in one half life
if you start with 10  you will get 5
if you start with 1,  you will get 1/2
the time doesn't change

anonymous · Answer

in days

anonymous · Answer

No=intial mass 
N=mass at time