SOLUTION: The concentration C of a drug in the bloodstream at time t (in hours) can be approximated by C=100(1-e^-0.5t). What will the concentration be after 8 hours? I am lost..... Pleas

Algebra ->  Exponential-and-logarithmic-functions -> SOLUTION: The concentration C of a drug in the bloodstream at time t (in hours) can be approximated by C=100(1-e^-0.5t). What will the concentration be after 8 hours? I am lost..... Pleas      Log On


   

Question 197953: The concentration C of a drug in the bloodstream at time t (in hours) can be approximated by C=100(1-e^-0.5t). What will the concentration be after 8 hours?
I am lost..... Please help. Thanks.
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
C=100%281-e%5E%28-0.5t%29%29 Start with the given equation.


C=100%281-e%5E%28-0.5%288%29%29%29 Plug in t=8


C=100%281-e%5E%28-4%29%29 Multiply -0.5 and 8 to get -4


C=100%281-0.01832%29 Evaluate e%5E%28-4%29 (by use of a calculator) to approximately get 0.01832


C=100%280.98168%29 Subtract


C=98.168 Multiply


So the concentration is approximately 98.168.


I'm assuming that we're talking about a percentage. If so, then there's about 98.168% of the drug left over after 8 hours.