SOLUTION: The half life of a specific radioactive compound is 15 years. The equation used to model this half-life is y=200(1/2)^t/15, where T represents time when 200 pounds of this substanc

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Question 1027560: The half life of a specific radioactive compound is 15 years. The equation used to model this half-life is y=200(1/2)^t/15, where T represents time when 200 pounds of this substance remaining. Determine approximately how much of the substance remains after 82 years. Round to the nearest tenth of a year.
Answer by fractalier(6550) About Me  (Show Source):
You can put this solution on YOUR website!
To do this, we wish to find the time t, where y = 82, so
y=200(1/2)^t/15
82=200(1/2)^t/15
.41 = (1/2)^t/15
ln .41 = (t/15)ln(1/2)
-.8916 = (t/15)*-.6931
t/15 = 1.2863
t = 19.3 years