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Bacteria culture starts with 300 bacteria

  1. Aug 3, 2010 #1
    1. The problem statement, all variables and given/known data

    and after 3 hours there are 600 bacteria. Assuming bacteria grow at rate proportinal to their size, which means you can use the function, y=Aekt, where y is the number of bacteria and t is time in hours.

    1) find the number of bacteria after 5 hours,
    2) when will the population reach 2,000?

    2. Relevant equations



    3. The attempt at a solution
    First, find k:
    600=300e3k
    2=e3k
    k=1/3*ln(2)=0.231

    1) y=300e5*0.231=952.207
    2) 2000=300e0.231t
    6.667=e0.231t
    t=1/0.231 ln (6.667)=8.21


    Please check my answers.
    J.
     
  2. jcsd
  3. Aug 4, 2010 #2

    HallsofIvy

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    Staff Emeritus
    Science Advisor

    Your first answer should not be a fraction- the "number of bacteria" must be an integer. Use 952.

    You should always include units. For number 2 your answer should be "8.21 hours".

    Other than that, they are correct.
     
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