<PRE><B>Question 439905</B>
The population of a certain country grows exponentially so that its doubling time is 42 years. If the present population is 12.5 million, what will the population be in 126 years? 
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A(t) = Ao*b^t
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2Ao = Ao*b^42
2 = b^42
b = 2^(1/42)
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A(0) = 12.5
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A(126) = 12.5*2^(126/42)
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A(126) = 12.5*2^3
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A(126) = 12.5*8 = 100 million
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Cheers,
Stan H.
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