my professor gave me this example during a lecture:
Doubling time of a population
70 divided by percentage growth rate
EXAMPLE: growth rate=3.5%; doubling time in years =20
i do not get how he got 20 years for the answer.
according to what he says, 70 is like a magic number, but i am sort of confused.
hope someone can help me out with this.
doubling time of population
2007-03-17 10:39 am
回答 (1)
2007-03-17 11:27 am
✔ 最佳答案
70 divided by percentage growth rate i.e. (70/3.5) = 20
another example:
Afghanistan has a current growth rate of 4.8%, representing a doubling time of approximately 14.5 years (70/4.8=14.5).
The length of time is determined by dividing the growth rate into 70. The number 70 comes from the natural log of 2, which is .70
you can check this out for more info on Exponential Growth and The Rule of 70
~:)
收錄日期: 2021-04-23 14:27:34
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