SOLUTION: A population of fish has an exponential growth rate of K=6% per year. How long will it take for the population to double?

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Question 1140587: A population of fish has an exponential growth rate of K=6% per year. How long will it take for the population to double?
Found 2 solutions by josgarithmetic, greenestamps:
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
y=p%2A1.06%5Ex
-
2=1.06%5Ex
log%28%282%29%29=x%2Alog%28%281.06%29%29
highlight%28x=log%28%282%29%29%2Flog%28%281.06%29%29%29
Put expression into a calculator for easier evaluation.

Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


P%28t%29+=+P%280%29%2A%281.06%5Et%29

You want P(t) to be twice P(0):

2%2AP%280%29+=+P%280%29%2A%281.06%29%5Et
2+=+1.06%5Et

The variable is in an exponent, so use logarithms:

log%28%282%29%29+=+log%28%281.06%5Et%29%29
log%28%282%29%29+=+t%2Alog%28%281.06%29%29
t+=+log%28%282%29%29%2Flog%28%281.06%29%29

Use a calculator....