SOLUTION: The number of insects attracted to a bright light is currently 8. If the number is expected to quadruple every 10 minutes, how long will it take for the number to reach 500?

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: The number of insects attracted to a bright light is currently 8. If the number is expected to quadruple every 10 minutes, how long will it take for the number to reach 500?      Log On


   

Question 326229: The number of insects attracted to a bright light is currently 8. If the number is expected to quadruple every 10 minutes, how long will it take for the number to reach 500?
Answer by stanbon(75887) About Me  (Show Source):
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The number of insects attracted to a bright light is currently 8. If the number is expected to quadruple every 10 minutes, how long will it take for the number to reach 500?
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A(t) = Ao(4)^(t/10) where t is in minutes.
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500 = 8*4^(t/10)
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4^(t/10) = 62.5
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Take the log and solve for "t":
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(t/10)*log(4) = log62.5
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t/10 = 2.9829
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t = 29.98
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Round up to t = 30 minutes
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Cheers,
Stan H.