SOLUTION: Suppose that the number of bacteria in a certain population increases according to a continuous exponential growth model. A sample of 2600 bacteria selected from this population

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Question 1204452: Suppose that the number of bacteria in a certain population increases according to a continuous exponential growth model. A sample of 2600 bacteria selected from this population reached the size of 2685 bacteria in one and a half hours. Find the hourly growth rate paramete
Found 2 solutions by josgarithmetic, ikleyn:
Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
If you try a model like y=ab%5Ex then you can put in your given information to make 2685=2600b%5E%281.5%29, and you should be able to solve that for b. To get the growth rate in the form of a decimal fraction, the b-1.

Answer by ikleyn(52790) About Me  (Show Source):
You can put this solution on YOUR website!
.
Suppose that the number of bacteria in a certain population increases according
to a continuous exponential growth model. A sample of 2600 bacteria selected
from this population reached the size of 2685 bacteria in one and a half hours.
Find the hourly growth rate paramete
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The exponential growth model is

    N = N%5B0%5D%2Ab%5Et,


N%5B0%5D is the initial population size, t is the time, "b" is the base of the exponential function.


For your problem, N%5B0%5D = 2600, t= 1.5 hours, N= 2685, so the equation takes the form

    2685 = 2600%2Ab%5E1.5.


Only base "b" is an unknown.  To find b, make these standard manipulations, step by step

    2685%2F2600 = b%5E1.5

    1.032692308 = b%5E1.5

    log(1.032692308) = 1.5*log(b)

    log(b) = log%28%281.032692308%29%29%2F1.5 = 0.009313961

    b = 10%5E0.009313961 = 1.021677811


ANSWER.  The base, or the exponential hourly rate of growth in this problem is 1.021677811.

         You may round it to 1.00931, for example.

Solved.