Population Model
In the absence of other pressures populations can be thought of as growing at a rate that is proportional to the number of members of the population, p:
where k is a constant indicating the rate, and t is time.
This gives an exponential growth of the population:
where p0 is the population at t=0, and p is the population at time t.
If the population doubles in a time tdouble then the rate k is
Rearranging this we have
The applet below will calculate the time taken to reach a given population from a given initial population.