SOLUTION: A cup of coffee contains 130 mg of caffeine. If caffeine is eliminated from the body at a rate of 11% per hour, how much caffeine will remain in the body after 3 hours? whats the

Algebra ->  Absolute-value -> SOLUTION: A cup of coffee contains 130 mg of caffeine. If caffeine is eliminated from the body at a rate of 11% per hour, how much caffeine will remain in the body after 3 hours? whats the      Log On


   



Question 823813: A cup of coffee contains 130 mg of caffeine. If caffeine is eliminated from the body at a rate of 11% per hour, how much caffeine will remain in the body after 3 hours?
whats the exponential function and answer?

Answer by TimothyLamb(4379) About Me  (Show Source):
You can put this solution on YOUR website!
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y(t) = a*e^(kt)
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now:
130 mg
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one hour from intake:
130 * (1 - 0.11) = 115.7 mg
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y(1) = 115.7 = 130*e^(k(1))
115.7 = 130*e^k
115.7/130 = e^k
ln( 115.7/130 ) = ln( e^k )
ln( 115.7/130 ) = k
k = -0.1165338
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three hours from intake:
y(3) = 130*e^(3k)
y(3) = 91.64597
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answer:
three hours after drinking a cup of coffee, 91.6 mg of caffeine will remain in the body
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