SOLUTION: The count in a bacteria culture was 200 after 15 minutes and 2000 after 40 minutes. Assuming the count grows exponentially, what is the doubling period?

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Question 1147675: The count in a bacteria culture was 200 after 15 minutes and 2000 after 40 minutes. Assuming the count grows exponentially,
what is the doubling period?
Found 2 solutions by josmiceli, ikleyn:
Answer by josmiceli(19441)   (Show Source): You can put this solution on YOUR website!



and



----------------------------------------

divide both sides by


Take the log base 10 of both sides


( I'll refer back to this step )


-----------------------------
To find doubling period:


Take log base 10 of both sides
( from the above mentioned step )


The doubling period is 7.526 min
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Get another opinion if needed
Answer by ikleyn(52898)   (Show Source): You can put this solution on YOUR website!
.

The shortest way to solve the problem is THIS:


     = 


    10 = .


Take logarithm base 2 of both sides.


     = t


Find    by any way you can.  // I use my MS Excel in my computer, as always.


    t = 3.32.


Thus 40-15 = 25 minutes  is 3.32 times the doubling period.


Hence, the doubling period is    = 7.5 minutes (approximately).    ANSWER

Solved.



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