Exponential Growth: doubling time 15 min; at t = 80, p = 70.

[celebrityrose000]

The doubling period of a baterial population is 15 minutes. At time t= 80 minutes, the bacterial population was 70,000. For some constant A, the formula for the population is

p(t) = Ae^(kt) where k=ln(2)/15.

what was the initial population at time t=0??

I'm not quite sure how to set this problem up.

I did 70,000 = A e^(ln2/15)(0) but the zero cancelled everything out. And you cant take the ln of zero.

Should I have set it up as 0 =Ae^(ln/15)(80)? I'm not sure how to set it up.

 

[Random]

Re: Exponential Growth Question

I did 70,000 = A e^(ln2/15)(0) but the zero cancelled everything out. And you cant take the ln of zero.

What is t when the population is 70,000? It isn't 0 like you have there...
Also, anything^0=1, not 0!