1. ## doubling period question....

The doubling period of a baterial population is minutes. At time minutes, the baterial population was 60000. With representing minutes, the formula for the population is .

1. ????
2. The initial population at time is???
3. The size of the baterial population after 3 hours is???

i've been trying to plug in and guess, but it's just not working...!!!!!

The doubling period of a baterial population is minutes. At time minutes, the baterial population was 60000. With representing minutes, the formula for the population is .

1. ????
2. The initial population at time is???
3. The size of the baterial population after 3 hours is???

i've been trying to plug in and guess, but it's just not working...!!!!!
$\displaystyle 60000 = Ae^{80k}$

$\displaystyle 30000 = Ae^{65k}$

divide the 1st equation by the 2nd one ...

$\displaystyle 2 = e^{15k}$

solve for $\displaystyle k$ ... then determine $\displaystyle A$ ... then find $\displaystyle P(180)$

3. i put .692/15 and got .046 but that does not seem to be the right value for K

i put .692/15 and got .046 but that does not seem to be the right value for K
why not ?

5. Originally Posted by skeeter
why not ?

because when i enter this into the system where I have to submit the answer, it prompts me by saying incorrect....

well ... I can guarantee that the exponential constant, $\displaystyle k$ , for any doubling period is $\displaystyle \frac{\ln(2)}{t}$ , where $\displaystyle t$ is the doubling period.
$\displaystyle \frac{\ln(2)}{15} = 0.046209812...$