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Math Help - exponential

  1. #1
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    exponential

    Please, can someone help me w/this?

    A biologist finds that the population of a certain type of bacteria doubles each half-hour. An initial culture has 90 bacteria. How long will it take for the number of bacteria to reach 368,640?

    Thank you.
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  2. #2
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    Quote Originally Posted by pexler View Post
    Please, can someone help me w/this?

    A biologist finds that the population of a certain type of bacteria doubles each half-hour. An initial culture has 90 bacteria. How long will it take for the number of bacteria to reach 368,640?

    Thank you.
    Hi

    Let n be the number of half-hours and q(n) the quantity of bacteria

    q(n) = 90 \cdot 2^n

    q(n) = 368,640 for \frac{368,640}{90} = 4096 = 2^n which gives n=12

    It will take 6 hours
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