<PRE><B>Question 548407</B>
The logistic growth function P(x)= 90/ 1+271e^(-.122x) models the percentage P(x), of Americans who are x years old and have some type of coronary heart disease. Use this function to find the age at which the percentage of Americans with some type of heart disease is 69%.
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69 = 90/[1+271e^(-0.122x)
1+271e^(-0.122x) = 90/69 = 1.3043
e^(-0.122x) = 0.3043/271
Take the natural log:
-0.122x = ln(0.3043/271) = -6.7917
x = 55.67 years of age
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Cheers,
Stan H.
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